• View in gallery

    Location of epithelial wounds created on a representative green iguana (Iguana iguana). A sterile 5-mm punch biopsy device was used to create 3 full-thickness skin wounds (circles) on the dorsum of each iguana; all wounds were approximately 1.0 cm lateral to the midline. The most cranial wound (a) was located just caudal to the level of the left axilla, the most caudal wound (b) was located at the level of the left midcoelom, and the third wound (c) was located at the level of the caudal aspect of the last right rib.

  • View in gallery

    Photomicrographs of the epithelium and underlying dermis of a representative green iguana obtained before (A) and after (B and C) treatment. In panel A, notice the epithelium (arrowhead) in anatomically normal skin. In panel B, mild healing is evident when there is regular epithelial migration (thin epithelial migration with no rete ridges [thick arrow]). In panel C, partial healing is evident when there is irregular epithelial migration (thickened epithelial projections with rete ridges [arrow]). H&E stain; bar = 500 μm.

  • 1. Mader DR, Bennett RA, Funk RS, et al. Surgery. In: Mader DR, ed. Reptile medicine and surgery. 2nd ed. St Louis: Saunders Elsevier, 2006;581630.

    • Search Google Scholar
    • Export Citation
  • 2. Mitchell MA, Diaz-Figueroa O. Wound management in reptiles. Vet Clin North Am Exot Anim Pract 2004;7:123140.

  • 3. Alibardi L. Ultrastructural features of the process of wound healing after tail and limb amputation in lizard. Acta Zoologica 2009;91:306318.

    • Search Google Scholar
    • Export Citation
  • 4. Peacock HM, Gilbert EAB, Vickaryous MK. Scar-free cutaneous wound healing in the leopard gecko, Eublepharis macularius. J Anat 2015;227:596610.

    • Search Google Scholar
    • Export Citation
  • 5. Smith DA, Barker IK. Healing of cutaneous wounds in the common garter snake (Thamnophis sirtalis). Can J Vet Res 1988;52:111119.

  • 6. Smith DA, Barker IK, Allen OB. The effect of ambient temperature and type of wound on healing of cutaneous wounds in the common garter snake (Thamnophis sirtalis). Can J Vet Res 1988;52:120128.

    • Search Google Scholar
    • Export Citation
  • 7. French SS, Matt KS, Moore MC. The effects of stress on wound healing in male tree lizards (Urosaurus ornatus). Gen Comp Endocrinol 2006;145:128132.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 8. Hernández-Divers SJ, Stahl SJ, Rakich PM, et al. Comparison of CO(2) laser and 4.0 MHz radiosurgery for making incisions in the skin and muscles of green iguanas (Iguana iguana). Vet Rec 2009;164:1316.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 9. Hodshon RT, Sura PA, Schumacher JP, et al. Comparison of first-intention healing of carbon dioxide laser, 4.0-MHz radiosurgery, and scalpel incisions in ball pythons (Python regius). Am J Vet Res 2013;74:499508.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10. Smith DA, Barker IK, Allen OB. The effect of certain topical medications on healing of cutaneous wounds in the common garter snake (Thamnophis sirtalis). Can J Vet Res 1988;52:129133.

    • Search Google Scholar
    • Export Citation
  • 11. McFadden MS, Bennett RA, Kinsel MJ, et al. Evaluation of the histologic reactions to commonly used suture materials in the skin and musculature of ball pythons (Python regius). Am J Vet Res 2011;72:13971406.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 12. Calisto FC, Calisto SL, Souza AP, et al. Use of low-power laser to assist the healing of traumatic wounds in rats. Acta Cir Bras 2015;30:204208.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 13. Figurová M, Valent L, Karasová M, et al. Histological assessment of a combined low-level laser/light-emitting diode therapy (685 nm/470 nm) for sutured skin incisions in a porcine model: a short report. Photomed Laser Surg 2016;34:5355.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 14. Hussein AJ, Alfars AA, Falih MA, et al. Effects of a low level laser on the acceleration of wound healing in rabbits. N Am J Med Sci 2011;3:193197.

    • Search Google Scholar
    • Export Citation
  • 15. Ahmed Omar MT, Ebid A, El Morsy A. Treatment of post-mastectomy lymphedema with laser therapy: double blind placebo control randomized study. J Surg Res 2011;165:8290.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 16. Karu TI. Molecular mechanism of low-power laser therapy. Lasers Life Sci 1998;2:5374.

  • 17. Karu T. Primary and secondary mechanisms of action of visible to near-IR radiation on cells. J Photochem Photobiol B 1999;49:117.

  • 18. Carvalho KC, Nicolau RA, Maia Filho AL, et al. Study of the strength of healing skin of rats treated with phototherapy in laser. Con Scientiae Saude 2010;9:179186.

    • Search Google Scholar
    • Export Citation
  • 19. Gonçalves RV, Novaes RD, do Carmo Cupertino M, et al. Time-dependent effects of low-level laser therapy on the morphology and oxidative response in the skin wound healing in rats. Lasers Med Sci 2013;28:383390.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 20. Millis DM, Saunders DG. Laser therapy in canine rehabilitation. In: Millis DM, Levine D, eds. Canine rehabilitation and physical therapy. 2nd ed. St Louis: Saunders Elsevier, 2013;359380.

    • Search Google Scholar
    • Export Citation
  • 21. Takhtfooladi MA, Sharifi D. A comparative study of red and blue light-emitting diodes and low-level laser in regeneration of the transected sciatic nerve after an end to end neurorrhaphy in rabbits. Lasers Med Sci 2015;30:23192324.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 22. Bhowmick D, Bhargava MK. Cold laser irradiation for biostimulation of wounds—a histological and histochemical study in bovine calves. Intas Polivet 2015;16:2631.

    • Search Google Scholar
    • Export Citation
  • 23. Chow RT, Johnson MI, Lopes-Martins RA, et al. Efficacy of low-level laser therapy in the management of neck pain: a systematic review and meta-analysis of randomised placebo or active-treatment controlled trials. Lancet 2009;374:18971908.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 24. Dancáková L, Poláková M, Kovác I, et al. Low-level laser therapy at 808 nm increases tensile strength of healing skin wounds in rats. Folia Vet 2012;5:3539.

    • Search Google Scholar
    • Export Citation
  • 25. Reddy GK, Stehno-Bittel L, Enwemeka CS. Laser photostimulation accelerates wound healing in diabetic rats. Wound Repair Regen 2001;9:248255.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 26. Rezende SB, Ribeiro MS, Núñez SC, et al. Effects of a single near-infrared laser treatment on cutaneous wound healing: biometrical and histological study in rats. J Photochem Photobiol B 2007;87:145153.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 27. Kurach LM, Stanley BJ, Gazzola KM, et al. The effect of low-level laser therapy on the healing of open wounds in dogs. Vet Surg 2015;44:988996.

  • 28. Stich AN, Rosenkrantz WS, Griffin CE. Clinical efficacy of low-level laser therapy on localized canine atopic dermatitis severity score and localized pruritic visual analog score in pedal pruritus due to canine atopic dermatitis. Vet Dermatol 2014;25:464e74.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 29. Mendez TM, Pinheiro AL, Pacheco MT, et al. Dose and wavelength of laser light have influence on the repair of cutaneous wounds. J Clin Laser Med Surg 2004;22:1925.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 30. Hirata K, Kawabuchi M. Myelin phagocytosis by macrophages and nonmacrophages during Wallerian degeneration. Microsc Res Tech 2002;57:541547.

  • 31. Cole GL, Lux CN, Schumacher JP, et al. Effect of laser treatment on first-intention incisional wound healing in ball pythons (Python regius). Am J Vet Res 2015;76:904912.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 32. Kraut S, Fischer D, Heuser W, et al. Laser therapy in a soft-shelled turtle (Pelodiscus sinensis) for the treatment of skin and shell ulceration. A case report. Tierarztl Prax Ausg K Kleintiere Heimtiere 2013;41:261266.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 33. Pelizzone I, Ianni F, Parmigiani E. Laser therapy for wound healing in chelonians: two case reports. Veterinaria 2014;28:3338.

  • 34. Enwemeka CS, Parker JC, Dowdy DS, et al. The efficacy of low-power lasers in tissue repair and pain control: a meta-analysis study. Photomed Laser Surg 2004;22:323329.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 35. Walsh LJ. The current status of low level laser therapy in dentistry. Soft tissue applications. Aust Dent J 1997;42:247254.

  • 36. Ghamsari SM, Taguchi K, Abe N, et al. Evaluation of low level laser therapy on primary healing of experimentally induced full thickness teat wounds in dairy cattle. Vet Surg 1997;26:114120.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 37. Vasilenko T, Slezak M, Kovác I, et al. The effect of equal daily dose achieved by different power densities of low-level laser therapy at 635 and 670 nm on wound tensile strength in rats: a short report. Photomed Laser Surg 2010;28:281283.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 38. Cho Lee AR, Leem H, Lee J, et al. Reversal of silver sulfadiazine-impaired wound healing by epidermal growth factor. Biomaterials 2005;26:46704676.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 39. Leitch IO, Kucukcelebi A, Robson MC. Inhibition of wound contraction by topical antimicrobials. Aust N Z J Surg 1993;63:289293.

  • 40. Muller MJ, Hollyoak MA, Moaveni Z, et al. Retardation of wound healing by silver sulfadiazine is reversed by Aloe vera and nystatin. Burns 2003;29:834836.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 41. Park MV, Neigh AM, Vermeulen JP, et al. The effect of particle size on the cytotoxicity, inflammation, developmental toxicity and genotoxicity of silver nanoparticles. Biomaterials 2011;32:98109817.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 42. Yaman I, Durmus AS, Ceribasi SM, et al. Effects of Nigella sativa and silver sulfadiazine on burn wound healing in rats. Vet Med 2010;55:619624.

  • 43. Rodrigo SM, Cunha A, Pozza DH, et al. Analysis of the systemic effect of red and infrared laser therapy on wound repair. Photomed Laser Surg 2009;27:929935.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 44. Schindl A, Heinze G, Schindl M, et al. Systemic effects of low-intensity laser irradiation on skin microcirculation in patients with diabetic microangiopathy. Microvasc Res 2002;64:240246.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 45. Smith J. 8 Whys, whens, and hows for deep tissue applicator (on contact) laser therapy. Available at: www.litecure.com/companion/laser-therapy. Accessed Feb 23, 2016.

    • Search Google Scholar
    • Export Citation

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Gross and histologic evaluation of effects of photobiomodulation, silver sulfadiazine, and a topical antimicrobial product on experimentally induced full-thickness skin wounds in green iguanas (Iguana iguana)

Lara M. Cusack DVM1, Joerg Mayer DVM, MS2, Daniel C. Cutler DVM3, Daniel R. Rissi DVM, PhD4, and Stephen J. Divers BMedVet, DZooMed5
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  • 1 Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
  • | 2 Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
  • | 3 Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
  • | 4 Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
  • | 5 Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.

Abstract

OBJECTIVE To assess effects of photobiomodulation, silver sulfadiazine, and a topical antimicrobial product for the treatment of experimentally induced full-thickness skin wounds in green iguanas (Iguana iguana).

ANIMALS 16 healthy subadult green iguanas.

PROCEDURES Iguanas were anesthetized, and three 5-mm cutaneous biopsy specimens were obtained from each iguana (day 0). Iguanas were randomly assigned to 2 treatment groups, each of which had a control treatment. Wounds in the topical treatment group received silver sulfadiazine, a topical antimicrobial product, or no treatment. Wounds in the laser treatment group received treatment with a class 4 laser at 5 or 10 J/cm2 or no treatment. Wound measurements were obtained daily for 14 days. Iguanas were euthanized, and treatment sites were evaluated microscopically to detect ulceration, bacterial contamination, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity.

RESULTS On day 14, wounds treated with a laser at 10 J/cm2 were significantly smaller than those treated with silver sulfadiazine, but there were no other significant differences among treatments. Histologically, there were no significant differences in ulceration, bacterial infection, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity among treatments.

CONCLUSIONS AND CLINICAL RELEVANCE Photobiomodulation at 10 J/cm2 appeared to be a safe treatment that was tolerated well by green iguanas, but it did not result in substantial improvement in histologic evidence of wound healing, compared with results for other treatments or no treatment.

Abstract

OBJECTIVE To assess effects of photobiomodulation, silver sulfadiazine, and a topical antimicrobial product for the treatment of experimentally induced full-thickness skin wounds in green iguanas (Iguana iguana).

ANIMALS 16 healthy subadult green iguanas.

PROCEDURES Iguanas were anesthetized, and three 5-mm cutaneous biopsy specimens were obtained from each iguana (day 0). Iguanas were randomly assigned to 2 treatment groups, each of which had a control treatment. Wounds in the topical treatment group received silver sulfadiazine, a topical antimicrobial product, or no treatment. Wounds in the laser treatment group received treatment with a class 4 laser at 5 or 10 J/cm2 or no treatment. Wound measurements were obtained daily for 14 days. Iguanas were euthanized, and treatment sites were evaluated microscopically to detect ulceration, bacterial contamination, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity.

RESULTS On day 14, wounds treated with a laser at 10 J/cm2 were significantly smaller than those treated with silver sulfadiazine, but there were no other significant differences among treatments. Histologically, there were no significant differences in ulceration, bacterial infection, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity among treatments.

CONCLUSIONS AND CLINICAL RELEVANCE Photobiomodulation at 10 J/cm2 appeared to be a safe treatment that was tolerated well by green iguanas, but it did not result in substantial improvement in histologic evidence of wound healing, compared with results for other treatments or no treatment.

Similar to the skin of higher vertebrates, reptile skin consists of an epidermis and dermis and acts as a physical barrier against pathogens and to prevent the loss of electrolytes and fluids. Integumentary injury is characterized initially by an inflammatory and vascular response. The inflammatory response in lizards may be minimal, compared with that in snakes.1,2 This is followed by a fibroblast response that is from the adjacent dermis, as opposed to the response in mammals that is from the underlying subcutaneous tissues.1,2 Restoration of the epidermis and maturation of the epithelium follow restoration of dermal integrity. The amount of scab formation can differ, with lizards generally forming little epithelial scab and snakes forming substantial scab. Mitotic activity of epidermal cells occurs only during times of ecdysis, which occurs simultaneously over the body in squamates (lizards and snakes).1,2

Although wound healing in reptiles occurs in the same general phases as that of mammals, it is at a slower rate, differs among reptilian species, and is affected by a variety of factors.2–4 The relatively slow rate of healing creates additional potential for contamination and bacterial colonization, which can delay wound healing.5 Wound healing in common garter snakes (Thamnophis sirtalis) is more rapid when animals are housed at the upper end of their preferred optimum temperature range,6 whereas restraint-associated stress in tree lizards (Urosauras ornatus) decreases healing of experimentally created cutaneous wounds.7 Other factors, such as the direction of an incision as well as the instrumentation used to create incisions, also affect wound healing in reptiles.1,5,8,9

Basic wound management of reptiles, including primary closure, healing by secondary intention, or delayed primary closure, parallels that of mammals, with irrigation, debridement, daily treatments, and bandaging considered standard practices.1,6,10 The type of wound management in both reptiles and other vertebrates can have important effects on wound healing.1 Because of the propensity for reptile skin to invert during the healing process, it is recommended that primary closure (if performed) be accomplished by the use of everting suture patterns, and recommendations for the most appropriate suture type for reptile skin have been reported.1,11 Healing by secondary intention may be more appropriate for certain wounds, such as those that are contaminated or are chronic in nature, although sequelae may include skin contracture, delayed wound healing, and incomplete epithelial coverage.1,2

A variety of modalities, including the use of topical treatments, wound dressings, and adjunct treatments, have been used in attempts to improve wound healing in reptiles. Use of topical antimicrobials and antiseptics have been documented in the human and veterinary literature and are typically aimed at a specific stage of the healing process. Assessment of the effects of various topical products as well as the use of various suture materials on wound healing in reptiles has revealed substantial variability, and some products have been found to delay wound healing.10 The variability in wound healing for products that are routinely used in nonreptilian patients supports the need for development of additional modalities for the treatment of wounds in reptiles. This is particularly true for wounds that heal by secondary intention.

Photobiomodulation has been used in both human and veterinary medicine because of its anti-inflammatory, analgesic, and wound-healing effects. Photobiomodulation improves the rate of healing in patients with epithelial trauma, musculoskeletal injuries, and chronic pain in multiple species, including rats,12 pigs,13 rabbits,14 and humans.15 By inducing a photochemical reaction at the cellular level, laser light stimulates a biochemical response that results in both local and systemic wound-healing effects. Absorption of photons by mitochondria of photo-responsive cells stimulates an increase in ATP,16,17 which makes energy available for a variety of cellular processes, including angiogenesis, fibroblast proliferation, transition of fibroblasts to myofibroblasts, collagen synthesis, and anti-inflammatory processes.18,19 Evidence for additional effects, such as analgesia and a reduction in edema, has been found in canine patients,20 and an increase in epithelialization in both primary- and secondary-intention healing has been reported for a variety of animals, including rabbits,21 rats,12 calves,22 humans,23 and pigs.13

Increased fibroblast proliferation and migration with a consequent increase in collagen production have also been attributed to laser treatment. Secondary effects of increased fibroblast production, including an increased rate of contraction of granulation tissue and increased tensile strength, have been reported in multiple studies24–26 on wound healing of rats. Despite the growing body of literature to support the clinical effects of photobiomodulation, studies27,28 of dogs revealed a lack of response to laser treatment when compared with control treatments. Additionally, there is evidence to support a decrease in wound healing with higher doses for laser treatments.29

Effects of photobiomodulation differ greatly depending on the wavelength, energy, energy density, duration, and delivery system.30 Discrepancies in results of wound-healing studies may be related to these variables, and it is difficult to make comparisons among studies because of the variability in treatment protocols. There is little information available on efficacy and safety of protocols for use of lasers in terms of wavelength, power, energy, and duration of treatment, particularly for exotic species. A recent study31 on the effects of photobiomodulation on primary-intention wound healing in ball pythons (Python reguis) revealed a significant improvement in collagen maturity at day 14, but there were no other significant improvements in wound healing during the 30-day study. Use of a laser for the treatment of skin and shell ulceration in a soft-shelled turtle (Pelodiscus sinensis)32 and for skin wounds in 2 species of chelonians (Testudo hermanni and Trachemys scripta)33 resulted in subjective improvements, but results were not verified by histologic examination.

The purpose of the study reported here was to investigate the effects of photobiomodulation on secondary-intention wound healing in green iguanas (Iguana iguana) and to compare effects with those for traditional topical treatments. We hypothesized that there would be no significant difference in healing among wounds regardless of treatment method.

Materials and Methods

Animals

Sixteen healthy subadult green iguanas were obtained from a commercial reptile wholesaler.a Initial examination was performed 1 day after iguanas arrived at our facility. Body weight was between 420 and 1,180 g (mean, 558.3 g), and results of physical examination were unremarkable. Iguanas were provided with a 7-day acclimation period prior to the study. Iguanas were housed in a room as a group and maintained with a photoperiod of 12 hours of light and 12 hours of darkness at a mean temperature of 26.6°C during the day and 23.9°C during the night. Multiple basking lights were provided in each corner of the room, with a daytime basking temperature of 33.3° to 35°C. Humidity was maintained at approximately 80% by the use of multiple tubs filled with water and a continuous slow-running tap. The diet consisted of mixed salad greens, and water was provided ad libitum. The study was approved by the University of Georgia Institute for Animal Care and Use Committee (A2015 09-015-Y1-A2).

Anesthesia and surgery

Food was removed 24 hours prior to surgery. The surgery room was located adjacent to the iguanas’ room; it was maintained between 29.4° and 35°C, which allowed for maintenance of the iguanas in the same husbandry conditions for a maximal amount of time. Iguanas were individually moved to the surgery room, administered an injection of hydromorphone (0.5 mg/kg, IM), and placed in an incubator maintained at 29.4°C. Vital signs (heart rate, respiratory rate, and surface body temperature) were assessed before the hydromorphone injection and throughout the procedures. Each iguana was removed from the incubator approximately 20 minutes after the hydromorphone injection, and anesthesia was induced with propofol (10 mg/kg, IV) administered in the ventral coccygeal vein. Isoflurane in oxygen was administered via a mask, as required, for maintenance of anesthesia.

The dorsum of each iguana was aseptically prepared with alternating washes of 4% chlorhexidine and sterile saline (0.9% NaCl) solution. A sterile 5-mm punch biopsy device was used to create 3 full-thickness skin wounds on the dorsum of each iguana (day 0). The same investigator (LMC) collected all skin biopsy specimens and created all skin wounds. All wounds were approximately 1 cm lateral to the dorsal midline. The most cranial wound (wound a) was located just caudal to the level of the left axilla; the most caudal wound (wound b) was located at the level of the left midcoelom, and the third wound (wound c) was located at the level of the caudal aspect of the last right rib (Figure 1).

All wounds were flushed with sterile saline solution to remove hemorrhage or tissue fluid. Skin samples were placed in tissue cassettes and fixed in neutral-buffered 10% formalin for histologic examination.

Once the righting reflex was evident and the iguanas were responsive to stimuli, they were transported back to the housing room. All iguanas fully recovered within 30 minutes after completion of the biopsy. Iguanas were monitored daily throughout the study period for clinical signs, including changes in mentation, appetite, body weight, activity, or vital signs that may have indicated pain or disease.

Wound treatment

Initial wound treatments were administered immediately after biopsy and were applied once daily for 14 days. Visual examination and measurement of each wound were performed once daily throughout the study. All wounds were flushed with sterile saline solution each day before treatments were applied, and all wounds were covered with identical sterile nonadherent dressings between daily treatments.

Iguanas were arbitrarily assigned to 2 treatment groups: the topical treatment group and the laser treatment group. Wounds on each iguana of the topical treatment group were treated as follows: wound a received a thin layer of silver sulfadiazine ointment applied with a sterile swab, wound b received 0.5 mL of a topical antimicrobial productb containing silver and a proprietary antimicrobial technology developed through research conducted by the Emerging Diseases Research Group at the University of Georgia, and wound c received no topical treatment (control treatment). Wounds on each iguana of the laser treatment group were treated as follows: wound a received 0.5 W for 60 seconds at 5 J/cm2, wound b received 1.0 W for 60 seconds at 10 J/cm2, and wound c received no laser treatment (control treatment).

Laser treatment involved use of a class 4 steady-state laser.c Laser treatments were applied with a tissue contact probe at a wavelength of 980 nm on a continuous wave sequence. The dorsum of each iguana, including the control wound, was covered with an opaque barrier. A 6-cm2 exposed area in the center of the barrier allowed treatment of each wound while ensuring that the remaining dorsal surface of the iguana was protected. The contact ball was placed perpendicular to, and in direct contact with, each wound. During treatment, the laser was slowly and continuously motioned to avoid accumulation of thermal energy, potential discomfort, or tissue trauma at any 1 location. All personnel involved in laser treatment wore safety goggles that were provided by the laser manufacturer and rated appropriately for the laser. The head and eyes of the iguana were covered during treatment by a hand of the person restraining the animal.

Histologic examination

Initial skin samples obtained by use of the 5-mm punch biopsy device were submitted for histologic examination. At the completion of the 14-day study period, iguanas were euthanized as part of an endoscopy training program. Iguanas were euthanized with an overdose of pentobarbital (60 to 100 mg/kg, IV). Immediately after iguanas were euthanized, 6-cm2 areas surrounding each wound were collected, placed in tissue cassettes, and fixed in neutral-buffered 10% formalin. All tissues were routinely processed, sectioned at a thickness of 5 μm, stained with H&E and Masson trichrome stains, and examined by a board-certified veterinary pathologist who was unaware of the treatment group. A complete gross postmortem examination was also performed. Any abnormal tissues were also submitted for histologic examination.

Figure 1—
Figure 1—

Location of epithelial wounds created on a representative green iguana (Iguana iguana). A sterile 5-mm punch biopsy device was used to create 3 full-thickness skin wounds (circles) on the dorsum of each iguana; all wounds were approximately 1.0 cm lateral to the midline. The most cranial wound (a) was located just caudal to the level of the left axilla, the most caudal wound (b) was located at the level of the left midcoelom, and the third wound (c) was located at the level of the caudal aspect of the last right rib.

Citation: American Journal of Veterinary Research 79, 4; 10.2460/ajvr.79.4.465

Samples were assessed histologically on the basis of a systematic evaluation of the epidermal and dermal changes, compared with results for anatomically normal control skin. Assessed epidermal changes included presence or absence of ulceration and bacterial contamination as well as reepithelialization (Appendix). Assessed dermal changes included inflammation, presence or absence of dermal necrosis, dermal fibrosis, and collagen maturity.

Statistical analysis

All analyses were performed by use of statistical software.d A generalized linear mixed model that included all measurements and assessed the correlation of measurements within each iguana was used to compare binomial and ordinal variables among treatments. A binomial distribution with a logit link function was used for binomial variables. A multinomial distribution with a cumulative logit link function was used for ordinal variables. An independent correlation structure was assumed. Fisher exact tests were used to compare pairs of treatments for ulceration among iguanas when there was quasiseparation of data (eg, 1 treatment had a 100% response). A repeated-measures analysis was used to compare differences in wound size among the 5 treatments. The full model included fixed factors of treatment, day, and the treatment-by-day interaction and a random intercept for each iguana. An unstructured covariance structure was assumed. Multiple comparisons were made by use of Tukey adjusted pair comparison tests. All hypothesis tests were 2-sided. Significance was set at values of P ≤ 0.05.

Results

Animals

All iguanas were considered healthy on the basis of results of physical and postmortem examinations. Examination of the initial biopsy specimens did not reveal histologic evidence of underlying disease or dermatologic abnormalities. Anesthesia, surgery, and recovery were unremarkable for all iguanas. On day 2, 1 iguana had an open wound involving the right stifle joint that was consistent with trauma from a conspecific or traumatic injury within the housing room. Because that wound did not respond after several days of topically applied treatment, and the iguana was scheduled to be euthanized after use in a terminal endoscopy training program, we elected to euthanize the iguana on day 5. Data for that iguana were not included in the study results. No other iguanas had clinical changes in behavior or signs of pain or illness.

Gross wound evaluation

Subjective evaluation of the wound sites immediately after biopsy revealed that the most cranial wound (wound a) had a mild amount of hemorrhage, whereas there was no notable hemorrhage at wounds b or c. This appeared to be related to a subjectively larger muscle mass cranially, compared with the muscle mass at the more caudal wounds. On the basis of daily visual examinations, there were no obvious signs of infection or inflammation throughout the study. Mean, SD, and minimum and maximum measurements of skin wounds were determined for days 1 and 14 (Table 1). There were no significant differences between control wounds for iguanas of the topical treatment and laser treatment group; therefore, results for both control treatments were pooled for statistical analysis. There were significant (P < 0.001) effects of treatment and day on wound size. On day 14, treatment with photobiomodulation at 10 J/cm2 resulted in a significantly (P = 0.002) smaller wound size than did treatment with silver sulfadiazine (Table 2). No other significant differences among treatment groups were evident at the end of the study.

Figure 2—
Figure 2—

Photomicrographs of the epithelium and underlying dermis of a representative green iguana obtained before (A) and after (B and C) treatment. In panel A, notice the epithelium (arrowhead) in anatomically normal skin. In panel B, mild healing is evident when there is regular epithelial migration (thin epithelial migration with no rete ridges [thick arrow]). In panel C, partial healing is evident when there is irregular epithelial migration (thickened epithelial projections with rete ridges [arrow]). H&E stain; bar = 500 μm.

Citation: American Journal of Veterinary Research 79, 4; 10.2460/ajvr.79.4.465

Table 1—

Measurements (mm) of the size of epithelial wounds in green iguanas (Iguana iguana) on day 14.*

TreatmentNo. of woundsMean ± SDMinimumMaximum
Silver sulfadiazine74.57 ± 0.534.005.00
Topical antimicrobial product73.43 ± 0.793.005.00
Control153.53 ± 0.743.005.00
Laser at 5 J/cm283.63 ± 1.062.005.00
Laser at 10 J/cm283.13 ± 0.992.005.00

Control represents a pooled value for all nontreated wounds.

Day of wound creation with a sterile 5-mm punch biopsy was day 0.

Table 2—

Comparison of wound size between treatments at the end of a 14-day study* of green iguanas.

Treatment comparisonP value
Silver sulfadiazine vs topical antimicrobial product0.083
Silver sulfadiazine vs control0.058
Silver sulfadiazine vs laser at 5 J/cm20.573
Silver sulfadiazine vs laser at 10 J/cm20.002
Topical antimicrobial product vs control1.000
Topical antimicrobial product vs laser at 5 J/cm21.000
Topical antimicrobial product vs laser at 10 J/cm21.000
Control vs laser at 5 J/cm21.000
Control vs laser at 10 J/cm21.000
Laser at 5 J/cm2 vs laser at 10 J/cm21.000

Values were considered significant at P ≤ 0.05 (repeated-measures analysis followed by Tukey adjusted pair comparison tests).

See Table 1 for key.

Histologic examination

There were no significant differences in presence of ulceration and bacteria as well as reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity among treatments (Figure 2; Tables 3 and 4). At day 14, 1 of 45 (2.2%) wounds had microscopic evidence of complete epithelial migration, whereas 35 of 45 (77.8%) wounds had moderate reepithelialization. At day 14, 2 of 45 (4.4%) wounds had a high degree of collagen maturity, whereas 35 of 45 (77.8%) had a moderate degree of collagen maturity, compared with results for anatomically normal skin.

Table 3—

Number of wounds with ulceration and bacteria in the epidermis and dermal necrosis at day 14* in green iguanas.

  Treatment
Skin layerVariableSilver sulfadiazineTopical antimicrobial productControlLaser at 5 J/cm2Laser at 10 J/cm2
EpidermisUlceration7/76/714/158/88/8
 Bacteria1/75/713/157/87/8
DermisNecrosis3/73/710/153/84/8

Values reported are number of wounds with the variable/total number of wounds treated. Control represents a pooled value for all nontreated wounds. Values did not differ significantly (P > 0.05; generalized linear mixed model) among treatments.

See Table 1 for remainder of key.

Table 4—

Number of wounds with epidermal healing and dermal inflammation, fibrosis, and collagen formation at day 14* in green iguanas.

    Degree of healing
Skin layerVariableTreatmentNo. of wounds0123
EpidermisReepithelializationSilver sulfadiazine70340
  Topical antimicrobial product70070
  Control1502121
  Laser at 5 J/cm280080
  Laser at 10 J/cm281340
  All451 (2.2)8 (17.8)35 (77.8)1 (2.2)
DermisInflammationSilver sulfadiazine70025
  Topical antimicrobial product71132
  Control150384
  Laser at 5 J/cm280062
  Laser at 10 J/cm280053
  All451 (2.2)4 (8.9)24 (53.3)16 (35.6)
DermisFibrosisSilver sulfadiazine70034
  Topical antimicrobial product70061
  Control1500105
  Laser at 5 J/cm280035
  Laser at 10 J/cm280062
  All450028 (62.2)17 (37.8)
DermisCollagen maturity§Silver sulfadiazine7NA070
  Topical antimicrobial product7NA250
  Control15NA3111
  Laser at 5 J/cm28NA071
  Laser at 10 J/cm28NA350
  Total45NA8 (17.8)35 (77.8)2 (4.4)

Control represents a pooled value for all nontreated wounds. Values in parentheses are percentages. Values did not differ significantly (P > 0.05; generalized linear mixed model) among treatments.

Scored on a scale of 0 to 3, with 0 = absent, 1 = mild, 2 = moderate, and 3 = complete.

Scored on a scale of 0 to 3, with 0 = absent, 1 = mild, 2 = moderate, and 3 = severe.

Scored on a scale of 1 to 3, with 1 = immature, 2 = moderately mature, and 3 = mature.

NA = Not applicable.

See Table 1 for remainder of key.

Independent of the assigned category, perivascular and interstitial inflammation consisted of lymphocytes and plasma cells, with variable numbers of heterophils and macrophages. Areas of dermal necrosis were typically surrounded by distinct layers of epithelioid macrophages and heterophils.

Discussion

Photobiomodulation has been used to improve tissue healing in human15,34,35 and veterinary25,26,36 medicine for several decades. Although there is increased epithelialization for both primary- and secondary-intention healing in multiple species treated with photobiomodulation,12,13,21,22 a recent study31 of the effects of therapeutic lasers on first-intention incisional wound healing in ball pythons (P reguis) did not reveal significant improvements in wound healing. Investigators of that study31 compared rate of healing and histologic wound reaction (reduced inflammation, necrosis, and edema) between wounds treated with therapeutic lasers and untreated control incisions in a population of 6 pythons. Although there was no significant difference in overall wound healing between treatment groups at day 30, the grade of collagen maturity at day 14 was significantly (P = 0.042) greater for the laser-treated group than the control group. Treatment of the pythons consisted of a power output of 0.5 W for 90 seconds once daily for 7 consecutive days, and the dose delivered to each incision was 5 J/cm2 with a wavelength of 980 nm on a continuous wave sequence. That treatment protocol was extrapolated from one used in mammals,37 and the authors acknowledged that the treatment regimen may have been insufficient because of possible greater reflection or absorption of photons by reptilian scales.9

The treatment protocol used for the iguanas of the study reported here involved photobiomodulation at the same dose as was used in the aforementioned python study31 (5 J/cm2) for 1 treatment and a higher setting (10 J/cm2; double the dose) for the second treatment. There were no significant differences in histologic evidence of healing between the laser treatments, topical treatments, and control treatments at 14 days, which was the end of the study. There were 35 of 45 (77.8%) wounds with moderate epithelialization and only 1 of 45 (2.2%) with complete epithelialization at the end of the study. Only 2 of 45 (4.4%) wounds had a high degree of collagen maturity at the end of the 14-day study period. Although histologic assessment revealed complete epidermal closure for 1 of 45 (2.2%) wounds, the minimum gross wound size at the end of the study period was 2 mm. This difference likely was related to inherent differences between histologic and gross visual assessment as well as subjective evaluation between investigators. Gross wound measurements were significantly smaller at day 14 for the high-dose laser treatment, compared with the measurements for wounds treated with silver sulfadiazine, but not when compared with measurements for the topical wound product or control treatments. No other significant differences in wound size at the end of the study were detected among treatments. Histologic assessment of additional slides or sections may have provided a more thorough assessment of wound closure, and it is possible that the discrepancy between gross and histologic assessment was, at least in part, attributable to the specific sections evaluated.

The relatively low rate of healing in wounds treated with silver sulfadiazine was interesting because that compound is a commonly used topical treatment for wounds in reptiles and other species. Silver sulfadiazine cream is potentially cytotoxic and has been found to retard wound contraction in rats.38–42 Additional assessment of the use of silver-based compounds on reptiles is warranted.

On the basis of results of previous studies6,9 that indicated temperature and stress play a role in wound healing in reptiles, environmental conditions and general care in the present study were intended to promote wound healing and were similar to those provided in a study9 of ball pythons. Environmental temperature was maintained at the upper end of the preferred optimal temperature zone for green iguanas, and efforts were made to minimize environmental stress (handling was not required for cleaning of the environment or provision of food and water, and environmental variables were maintained consistently throughout the study).

A difference between a study31 of ball pythons and the study reported here was the use of control treatments. In that python study,31 1 group of incisions on an individual snake served as the control treatment for a photobiomodulation-treated incision on the same snake. Each snake received laser treatment, and true control incisions were not used to assess healing effects. For laser treatments, it has been reported that systemic effects can be observed in areas distant from the site of localized treatment. A study43 of rats revealed that the application of laser treatment directly to standardized skin wounds stimulated healing of treated wounds as well as healing of wounds distant from the point of laser application. Additionally, wounds located at the site of laser application had the lowest mean ranks of healing and those at an intermediate site had the highest ranks of healing.43 Furthermore, a systemic effect of laser treatment was also noted on the third day in wounds located most distant from the point of laser application.43 Consequently, in the study reported here, laser and topical treatments were not applied to the same animals. In contrast to the python study,31 the present study had 1 group of iguanas that received treatment with photobiomodulation and a second group of iguanas that received topical treatments. Untreated control wounds were present on each iguana. Given the potential systemic effects of lasers, treatment and control sites should be included on both laser-treated and nonlaser-treated groups to evaluate this potential effect.43,44 Because there were no significant differences between control treatments for the laser and topical treatment groups of the study reported here, it did not appear that there were substantial distant effects of the laser treatment for the iguanas of the present study.

The present study had several potential limitations that may have affected results. A subjective difference in thickness of the epithelium and underlying muscle as well as the vascular supply was detected among treatment sites on the iguanas, with the most cranial wounds having a larger muscle mass and more hemorrhage than the midbody and caudal wounds. A larger sample size could allow for consistency in placement of wounds and elimination of potential variability associated with wound location on the body and would also allow the use of other laser protocols. Although significant differences in wound measurements were detected among treatments in the present study, it was not possible (because of personnel limitations) to blind investigators who performed wound measurements. For future studies, blinding of wound assessors would remove the potential for bias in measurements and strengthen the results.

No significant improvement for histologic examination of overall healing was detected in the present study. However, it is possible that histologic assessment of additional sections and at multiple time points or a study with a longer duration may allow better assessment of healing among treatments. The low percentage of wounds (2.2%) that had complete epithelialization and a high degree of collagen maturity (4.4%) may support the need for an extended study period. Additionally, the small sample size for the present study may have limited the ability to detect small differences among treatments.

Additional considerations for future studies should include investigation of the photobiomodulation treatment protocol that may be most appropriate for reptile skin. It has been stated43 that higher fluency (> 10 J/cm2) can slow healing in mammalian wounds. However, treatment at 10 J/cm2 appeared to be well tolerated by iguanas of the present study, with no adverse signs noted. On the basis of results for the present study, treating skin lesions in green iguanas with lasers at doses of 10 J/cm2 appeared to be a safe method. The deep tissue applicator, which was used in the present study and allows wound contact, results in much less light being reflected from the skin, with 90% more photons reaching the tissue than for a noncontact handheld applicator.45 This may be of particular importance when treating reptiles because of the potential for increased reflectivity from, or absorption by, reptile scales. Although results of the study reported here did not indicate substantial benefits of laser treatment at 5 or 10 J/cm2, additional research into other doses and treatment protocols for wounds of reptiles may reveal efficacy of photobiomodulation treatments in wound healing of reptiles.

Acknowledgments

Supported by The Pamela de Journo Endowment Fund at the University of Georgia and by LiteCure.

Presented in abstract form at the Exoticscon Conference, Portland, Ore, August-September 2016.

The authors thank Nia Chau for technical assistance.

Footnotes

a.

Strictly Reptile Inc, Hollywood, Fla.

b.

Silvion, Molecular Therapeutics LLC, Athens, Ga.

c.

CTX therapy laser, provided by LiteCure, Newark, Del.

d.

SAS, version 9.3, SAS Institute Inc, Cary, NC.

References

  • 1. Mader DR, Bennett RA, Funk RS, et al. Surgery. In: Mader DR, ed. Reptile medicine and surgery. 2nd ed. St Louis: Saunders Elsevier, 2006;581630.

    • Search Google Scholar
    • Export Citation
  • 2. Mitchell MA, Diaz-Figueroa O. Wound management in reptiles. Vet Clin North Am Exot Anim Pract 2004;7:123140.

  • 3. Alibardi L. Ultrastructural features of the process of wound healing after tail and limb amputation in lizard. Acta Zoologica 2009;91:306318.

    • Search Google Scholar
    • Export Citation
  • 4. Peacock HM, Gilbert EAB, Vickaryous MK. Scar-free cutaneous wound healing in the leopard gecko, Eublepharis macularius. J Anat 2015;227:596610.

    • Search Google Scholar
    • Export Citation
  • 5. Smith DA, Barker IK. Healing of cutaneous wounds in the common garter snake (Thamnophis sirtalis). Can J Vet Res 1988;52:111119.

  • 6. Smith DA, Barker IK, Allen OB. The effect of ambient temperature and type of wound on healing of cutaneous wounds in the common garter snake (Thamnophis sirtalis). Can J Vet Res 1988;52:120128.

    • Search Google Scholar
    • Export Citation
  • 7. French SS, Matt KS, Moore MC. The effects of stress on wound healing in male tree lizards (Urosaurus ornatus). Gen Comp Endocrinol 2006;145:128132.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 8. Hernández-Divers SJ, Stahl SJ, Rakich PM, et al. Comparison of CO(2) laser and 4.0 MHz radiosurgery for making incisions in the skin and muscles of green iguanas (Iguana iguana). Vet Rec 2009;164:1316.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 9. Hodshon RT, Sura PA, Schumacher JP, et al. Comparison of first-intention healing of carbon dioxide laser, 4.0-MHz radiosurgery, and scalpel incisions in ball pythons (Python regius). Am J Vet Res 2013;74:499508.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10. Smith DA, Barker IK, Allen OB. The effect of certain topical medications on healing of cutaneous wounds in the common garter snake (Thamnophis sirtalis). Can J Vet Res 1988;52:129133.

    • Search Google Scholar
    • Export Citation
  • 11. McFadden MS, Bennett RA, Kinsel MJ, et al. Evaluation of the histologic reactions to commonly used suture materials in the skin and musculature of ball pythons (Python regius). Am J Vet Res 2011;72:13971406.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 12. Calisto FC, Calisto SL, Souza AP, et al. Use of low-power laser to assist the healing of traumatic wounds in rats. Acta Cir Bras 2015;30:204208.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 13. Figurová M, Valent L, Karasová M, et al. Histological assessment of a combined low-level laser/light-emitting diode therapy (685 nm/470 nm) for sutured skin incisions in a porcine model: a short report. Photomed Laser Surg 2016;34:5355.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 14. Hussein AJ, Alfars AA, Falih MA, et al. Effects of a low level laser on the acceleration of wound healing in rabbits. N Am J Med Sci 2011;3:193197.

    • Search Google Scholar
    • Export Citation
  • 15. Ahmed Omar MT, Ebid A, El Morsy A. Treatment of post-mastectomy lymphedema with laser therapy: double blind placebo control randomized study. J Surg Res 2011;165:8290.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 16. Karu TI. Molecular mechanism of low-power laser therapy. Lasers Life Sci 1998;2:5374.

  • 17. Karu T. Primary and secondary mechanisms of action of visible to near-IR radiation on cells. J Photochem Photobiol B 1999;49:117.

  • 18. Carvalho KC, Nicolau RA, Maia Filho AL, et al. Study of the strength of healing skin of rats treated with phototherapy in laser. Con Scientiae Saude 2010;9:179186.

    • Search Google Scholar
    • Export Citation
  • 19. Gonçalves RV, Novaes RD, do Carmo Cupertino M, et al. Time-dependent effects of low-level laser therapy on the morphology and oxidative response in the skin wound healing in rats. Lasers Med Sci 2013;28:383390.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 20. Millis DM, Saunders DG. Laser therapy in canine rehabilitation. In: Millis DM, Levine D, eds. Canine rehabilitation and physical therapy. 2nd ed. St Louis: Saunders Elsevier, 2013;359380.

    • Search Google Scholar
    • Export Citation
  • 21. Takhtfooladi MA, Sharifi D. A comparative study of red and blue light-emitting diodes and low-level laser in regeneration of the transected sciatic nerve after an end to end neurorrhaphy in rabbits. Lasers Med Sci 2015;30:23192324.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 22. Bhowmick D, Bhargava MK. Cold laser irradiation for biostimulation of wounds—a histological and histochemical study in bovine calves. Intas Polivet 2015;16:2631.

    • Search Google Scholar
    • Export Citation
  • 23. Chow RT, Johnson MI, Lopes-Martins RA, et al. Efficacy of low-level laser therapy in the management of neck pain: a systematic review and meta-analysis of randomised placebo or active-treatment controlled trials. Lancet 2009;374:18971908.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 24. Dancáková L, Poláková M, Kovác I, et al. Low-level laser therapy at 808 nm increases tensile strength of healing skin wounds in rats. Folia Vet 2012;5:3539.

    • Search Google Scholar
    • Export Citation
  • 25. Reddy GK, Stehno-Bittel L, Enwemeka CS. Laser photostimulation accelerates wound healing in diabetic rats. Wound Repair Regen 2001;9:248255.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 26. Rezende SB, Ribeiro MS, Núñez SC, et al. Effects of a single near-infrared laser treatment on cutaneous wound healing: biometrical and histological study in rats. J Photochem Photobiol B 2007;87:145153.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 27. Kurach LM, Stanley BJ, Gazzola KM, et al. The effect of low-level laser therapy on the healing of open wounds in dogs. Vet Surg 2015;44:988996.

  • 28. Stich AN, Rosenkrantz WS, Griffin CE. Clinical efficacy of low-level laser therapy on localized canine atopic dermatitis severity score and localized pruritic visual analog score in pedal pruritus due to canine atopic dermatitis. Vet Dermatol 2014;25:464e74.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 29. Mendez TM, Pinheiro AL, Pacheco MT, et al. Dose and wavelength of laser light have influence on the repair of cutaneous wounds. J Clin Laser Med Surg 2004;22:1925.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 30. Hirata K, Kawabuchi M. Myelin phagocytosis by macrophages and nonmacrophages during Wallerian degeneration. Microsc Res Tech 2002;57:541547.

  • 31. Cole GL, Lux CN, Schumacher JP, et al. Effect of laser treatment on first-intention incisional wound healing in ball pythons (Python regius). Am J Vet Res 2015;76:904912.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 32. Kraut S, Fischer D, Heuser W, et al. Laser therapy in a soft-shelled turtle (Pelodiscus sinensis) for the treatment of skin and shell ulceration. A case report. Tierarztl Prax Ausg K Kleintiere Heimtiere 2013;41:261266.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 33. Pelizzone I, Ianni F, Parmigiani E. Laser therapy for wound healing in chelonians: two case reports. Veterinaria 2014;28:3338.

  • 34. Enwemeka CS, Parker JC, Dowdy DS, et al. The efficacy of low-power lasers in tissue repair and pain control: a meta-analysis study. Photomed Laser Surg 2004;22:323329.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 35. Walsh LJ. The current status of low level laser therapy in dentistry. Soft tissue applications. Aust Dent J 1997;42:247254.

  • 36. Ghamsari SM, Taguchi K, Abe N, et al. Evaluation of low level laser therapy on primary healing of experimentally induced full thickness teat wounds in dairy cattle. Vet Surg 1997;26:114120.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 37. Vasilenko T, Slezak M, Kovác I, et al. The effect of equal daily dose achieved by different power densities of low-level laser therapy at 635 and 670 nm on wound tensile strength in rats: a short report. Photomed Laser Surg 2010;28:281283.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 38. Cho Lee AR, Leem H, Lee J, et al. Reversal of silver sulfadiazine-impaired wound healing by epidermal growth factor. Biomaterials 2005;26:46704676.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 39. Leitch IO, Kucukcelebi A, Robson MC. Inhibition of wound contraction by topical antimicrobials. Aust N Z J Surg 1993;63:289293.

  • 40. Muller MJ, Hollyoak MA, Moaveni Z, et al. Retardation of wound healing by silver sulfadiazine is reversed by Aloe vera and nystatin. Burns 2003;29:834836.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 41. Park MV, Neigh AM, Vermeulen JP, et al. The effect of particle size on the cytotoxicity, inflammation, developmental toxicity and genotoxicity of silver nanoparticles. Biomaterials 2011;32:98109817.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 42. Yaman I, Durmus AS, Ceribasi SM, et al. Effects of Nigella sativa and silver sulfadiazine on burn wound healing in rats. Vet Med 2010;55:619624.

  • 43. Rodrigo SM, Cunha A, Pozza DH, et al. Analysis of the systemic effect of red and infrared laser therapy on wound repair. Photomed Laser Surg 2009;27:929935.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 44. Schindl A, Heinze G, Schindl M, et al. Systemic effects of low-intensity laser irradiation on skin microcirculation in patients with diabetic microangiopathy. Microvasc Res 2002;64:240246.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 45. Smith J. 8 Whys, whens, and hows for deep tissue applicator (on contact) laser therapy. Available at: www.litecure.com/companion/laser-therapy. Accessed Feb 23, 2016.

    • Search Google Scholar
    • Export Citation

Appendix

Histologic assessment of epithelial wounds in green iguanas (Iguana iguana).

Skin layerVariableCategorization
EpidermisUlcerationAbsent or present
 Bacteria*Absent or present
 Reepithelialization0 = Absent, 1 = mild (regular, thin epithelial migration with no rete ridges), 2 = partial (irregular, thickened epithelial projections with rete ridges), or 3 = complete (complete epithelial migration)
DermisNecrosisAbsent or present
 Inflammation0 = Absent, 1 = mild (scattered perivascular accumulations of inflammatory cells), 2 = moderate (perivascular and interstitial accumulations of inflammatory cells), or 3 = severe (coalescing areas of perivascular and interstitial accumulations of inflammatory cells)
 Fibrosis0 = Absent, 1 = mild (scattered fibers), 2 = moderate (collagen fibers accumulated in the dermis), or 3 = severe (accumulated collagen fibers and distorted adjacent tissues)
 Collagen maturity1 = Immature (thin, wispy, light blue-stained collagen), 2 = moderately mature (scattered, blue-stained collagen bundles), or 3 = mature (thick blue-stained collagen bundles similar to adjacent normal dermis)

Visual detection of large aggregates of bacteria on the epidermis or ulcer surface.

Assessed by use of Masson trichrome stain.

Contributor Notes

Dr. Cusack's present address is Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, 298 Sabal Palm Rd, Naples, FL 34114.

Address correspondence to Dr. Cusack (laracusack@gmail.com).