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Abstract

OBJECTIVE To determine degrees of production of cyclooxygenase (COX)-1 and -2 and other mediators of inflammation in noninflamed and inflamed skin and muscle tissues in ball pythons (Python regius).

ANIMALS 6 healthy adult male ball pythons.

PROCEDURES Biopsy specimens of noninflamed skin and muscle tissue were collected from anesthetized snakes on day 0. A 2-cm skin and muscle incision was then made 5 cm distal to the biopsy sites with a CO2 laser to induce inflammation. On day 7, biopsy specimens of skin and muscle tissues were collected from the incision sites. Inflamed and noninflamed tissue specimens were evaluated for production of COX-1, COX-2, phosphorylated protein kinase B (AKT), total AKT, nuclear factor κ-light-chain-enhancer of activated B cells, phosphorylated extracellular receptor kinases (ERKs) 1 and 2, and total ERK proteins by western blot analysis. Histologic evaluation was performed on H&E-stained tissue sections.

RESULTS All biopsy specimens of inflamed skin and muscle tissues had higher histologic inflammation scores than did specimens of noninflamed tissue. Inflamed skin specimens had significantly greater production of COX-1 and phosphorylated ERK than did noninflamed skin specimens. Inflamed muscle specimens had significantly greater production of phosphorylated ERK and phosphorylated AKT, significantly lower production of COX-1, and no difference in production of COX-2, compared with production in noninflamed muscle specimens.

CONCLUSIONS AND CLINICAL RELEVANCE Production of COX-1, but not COX-2, was significantly greater in inflamed versus noninflamed skin specimens from ball pythons. Additional research into the reptilian COX signaling pathway is warranted.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To validate primer sets for use in reverse transcription quantitative PCR assays to measure gene expression of cytosolic phospholipase A2 (cPLA2) and microsomal prostaglandin E2 synthase 1 (mPGES1) in equine mononuclear cells and determine the effects of firocoxib, a selective cyclooxygenase 2 (COX-2) inhibitor, on COX-2, cPLA2, and mPGES1 gene expression following incubation of mononuclear cells with lipopolysaccharide (LPS).

ANIMALS 8 healthy adult horses.

PROCEDURES Peripheral blood mononuclear cells were isolated by density gradient centrifugation and incubated at 37°C with medium alone, firocoxib (100 ng/mL), LPS (1 ng/mL or 1 μg/mL), or combinations of firocoxib and both LPS concentrations. After 4 hours, supernatants were collected and tested for prostaglandin E2 (PGE2) concentration with an enzyme inhibition assay, and gene expression in cell lysates was measured with PCR assays.

RESULTS Primer pairs for cPLA2 and mPGES1 yielded single products on dissociation curve analyses, with mean assay efficiencies of 102% and 100%, respectively. Incubation with firocoxib and LPS significantly decreased PGE2 supernatant concentrations and significantly reduced COX-2 and mPGES1 gene expression, compared with values following incubation with LPS alone.

CONCLUSIONS AND CLINICAL RELEVANCE Primer sets for mPGES1 and cPLA2 gene expression in equine mononuclear cells were successfully validated. Firocoxib significantly decreased LPS-induced COX-2 and mPGES1 expression, suggesting that it may be useful in the control of diseases in which expression of these genes is upregulated.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To measure changes in interleukin-8 (IL-8), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) concentrations in stored canine packed RBCs (PRBCs) over time and assess the effect of leukoreduction on these cytokine concentrations.

ANIMALS 12 anesthetized healthy Greyhounds.

PROCEDURES 1 unit of whole blood from each dog was processed into PRBCs. Half of each PRBCs unit was passed through a leukoreduction filter to produce a leukoreduced unit, and the remaining blood was kept as a nonleukoreduced unit. All units had a CBC performed on day 0 (day of collection) and were stored at 2° to 6°C. Samples were collected from leukoreduced and nonleukoreduced units on days 0, 10, 20, 30, and 37 and centrifuged; the supernatant was stored at −80°C until analysis. Canine TNF-α and IL-8 concentrations were assessed with a multiplexed genomic and proteomic biomarker analyzer, and canine IL-1β concentration was measured by ELISA.

RESULTS Leukocyte counts were decreased by ≥ 99.9% in all leukoreduced units. Median TNF-α and IL-1β concentrations were not significantly different between leukoreduced and nonleukoreduced units and did not change significantly during storage; median IL-8 concentration was significantly higher in nonleukoreduced versus leukoreduced units on all days, and was greater at all time points after ≥ 10 days of storage than on day 0. Median IL-8 concentration in leukoreduced units did not increase during storage.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that leukoreduction was effective for the removal of leukocytes from canine PRBCs and prevented significant increases in IL-8 concentration during storage. Further studies are needed to evaluate whether leukoreduction reduces cytokine-associated complications of transfusion.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To investigate the association of bovine respiratory disease (BRD) or vaccination with serologic response in calves.

ANIMALS 94 Holstein calves.

PROCEDURES To assess the association between BRD and antibody titers, 38 calves < 3 months old that were treated for BRD were matched with 38 untreated calves. To investigate the effect of vaccination on antibody titers, 24 calves were randomly assigned to be vaccinated against bovine respiratory syncytial virus (BRSV), bovine viral diarrhea virus types 1 and 2, bovine herpesvirus type 1 (BHV1), and parainfluenza virus type 3 at 2 weeks of age (n = 6), 5 weeks of age (6), and both 2 and 5 weeks of age (6) or were assigned to be unvaccinated controls (6). Blood samples were obtained at I, 2, 5, and 12 weeks for determination of serum neutralization antibody titers against the vaccine viruses, bovine coronavirus, and Mannheimia haemolytica. Antibody rates of decay were calculated.

RESULTS Calves with initial antibody titers against BRSV < 1:64 that were treated for BRD had a slower rate of anti-BRSV antibody decay than did similar calves that were not treated for BRD. Calves with high initial antibody titers against BRSV and BHV1 had lower odds of BRD than did calves with low initial antibody titers against those 2 pathogens. Vaccination at 2 or 5 weeks of age had no effect on the rate of antibody decay.

CONCLUSIONS AND CLINICAL RELEVANCE Clinical BRD and the serologic response of dairy calves were associated with initial antibody titers against BRSV and BHV1. Serologic or clinical responses to viral exposure may differ in calves with low passive immunity.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To evaluate effects of various doses of polyethylene glycol (PEG)–conjugated bovine granulocyte colony-stimulating factor (bG-CSF) on the incidence of naturally occurring clinical mastitis in periparturient dairy cattle.

ANIMALS 211 periparturient Holstein cows and heifers.

PROCEDURES Approximately 7 days before the anticipated date of parturition (day of parturition = day 0), healthy cattle received SC injections of sterile saline (0.9% NaCl) solution (control treatment) or PEG–bG-CSF at 5, 10, or 20 μg/kg. Cattle were commingled and housed in a pen with dirt flooring, which was kept wet to maximize the incidence of naturally occurring clinical mastitis. Within 24 hours after parturition, each animal again received the assigned treatment. Mammary glands and milk were visually scored for abnormalities twice daily for 28 days after parturition. Milk samples were aseptically collected from mammary glands with an abnormal appearance or abnormal milk and submitted for microbial culture. Daily milk production was recorded, and milk composition was assessed on days 3, 5, 7, and 10.

RESULTS Cattle treated with PEG–bG-CSF at 10 and 20 μg/kg had significantly fewer cases of clinical mastitis (9/54 and 5/53, respectively), compared with control cattle (18/53). Administration of PEG –bG-CSF did not significantly affect daily milk production or milk composition.

CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that PEG–bG-CSF was effective for reducing the incidence of naturally occurring clinical mastitis in periparturient dairy cattle. Further investigations of the use of PEG–bG–CSF as a potential preventative intervention should be conducted.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate immunomodulatory properties of all-trans retinoic acid and a fully oxidized β-carotene dietary product in calves with Mannheimia haemolytica–induced pneumonia.

Animals—Twenty-five 6- to 10-week-old male Holstein calves for experimental inoculations and three 8- to 30-week-old Angus heifers for blood donations.

Procedures—In vitro, neutrophils and monocyte-derived macrophages isolated from blood of healthy Angus heifers were treated with all-trans retinoic acid (1μM) or fully oxidized β-carotene (8.3 μg/mL) for various times and assessed for markers of cellular death, antimicrobial function, and production of proinflammatory leukotriene B4. Following 28 days of dietary supplementation with fully oxidized β-carotene, Holstein calves were experimentally inoculated with M haemolytica. Bronchoalveolar lavage fluid was collected at 3 and 24 hours after challenge inoculation and analyzed for markers of apoptosis.

Results—In vitro, all-trans retinoic acid and fully oxidized β-carotene induced cell-selective, caspase-3–dependent apoptosis in neutrophils, which subsequently enhanced efferocytosis in macrophages. Conversely, neither treatment altered phorbol 12-myristate 13-acetate–induced oxidative burst, phagocytosis of nonopsonized zymosan (complement or antibody independent), or M haemolytica–induced leukotriene B4 production in bovine neutrophils. In vivo, fully oxidized β-carotene enhanced leukocyte apoptosis in bronchoalveolar lavage fluid as well as subsequent efferocytosis by macrophages without altering numbers of circulating leukocytes.

Conclusions and Clinical Relevance—Neutrophil apoptosis and subsequent efferocytosis by macrophages are key mechanisms in the resolution of inflammation. Findings for the present study indicated that all-trans retinoic acid and fully oxidized β-carotene could be novel nutraceutical strategies that may confer anti-inflammatory benefits for cattle with respiratory tract disease.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effects of resveratrol (RES) on growth and immune status in chickens receiving conventional vaccinations.

Animals—Two hundred forty 1-day-old layer chickens.

Procedures—Chickens received conventional vaccinations throughout the study and were randomly assigned to 1 of 4 treatments in 6 replicate pens/treatment. Treatments included 1 control group (basal diet) and 3 experimental groups fed the basal diet plus 200, 400, and 800 mg of RES/kg of diet. At 40 days of age, 1 bird/pen was randomly selected to have blood and tissues collected to determine serum immunity indices; mRNA relative expression of proinflammatory cytokines in splenocytes; mRNA relative expression of nuclear transcription factor-κB, growth hormone receptor, and insulin-like growth factor-1 in hepatocytes; cell proliferation; and apoptosis.

Results—Average daily gain, antibody titers against Newcastle disease virus and avian influenza viruses H5 and H9, and insulin-like growth factor-1 expression were quadratically increased with increasing RES concentration. In hepatocytes, growth hormone receptor gene mRNA relative expression was quadratically increased and nuclear transcription factor-κB gene mRNA relative expression was linearly decreased with increasing RES concentration. In splenocytes, nterleukin-1β and tumor necrosis factor-α mRNA relative expression was linearly decreased with increasing RES concentration. Resveratrol supplementation delayed cell proliferation and reduced apoptosis in immunocytes. With increasing RES concentration, proliferation index and relative weight of the thymus, ratio of CD4+ to CD8+ cells, and CD4+ cell count were quadratically increased, and IgM concentration was linearly increased.

Conclusions and Clinical Relevance—Dietary resveratrol supplementation improved growth, protected immunocytes against antigen-induced apoptosis, and upregulated immune response in chickens that received conventional vaccinations.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To characterize systemic immune responses in Cytauxzoon felis-infected cats.

Sample—Blood and lung samples obtained from 27 cats.

Procedures—Cats were allocated into 4 groups: cats that died of cytauxzoonosis, acutely ill C felis-infected cats, healthy survivors of C felis infection, and healthy uninfected cats. Serum concentrations of tumor necrosis factor-α and interleukin-1 β were measured and serum proteins characterized. Blood smears were stained immunocytochemically and used to assess immunoglobulin deposition. Immunohistochemical expression of CD18 and tumor necrosis factor-α were compared in lung tissues obtained from cats that died and healthy uninfected cats. A real-time reverse-transcription PCR assay for CD18 expression was performed on selected blood samples from all groups.

Results—Concentrations of both cytokines were greater and serum albumin concentrations were significantly lower in cats that died of cytauxzoonosis, compared with results for all other groups. Erythrocytes from acutely ill cats and survivors of C felis infection had staining for plasmalemmal IgM, whereas erythrocytes from the other groups did not. Increased staining of C felis-infected monocytes and interstitial neutrophils for CD18 was detected. The real-time reverse-transcription PCR assay confirmed a relative increase in CD18 expression in cats that died of cytauxzoonosis and acutely ill cats, compared with expression in other groups. Immunostaining for TNF-α in lung samples confirmed a local proinflammatory response.

Conclusions and Clinical Relevance—Results indicated immunopathologic responses were greater in cats that died of C felis infection than in cats that survived C felis infection.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether parenteral l-alanyl-l-glutamine (Ala-Gln) administration modulated phagocytic responses of polymorphonuclear neutrophilic leukocytes (PMNs) from dogs undergoing high-dose methylprednisolone sodium succinate (MPSS) treatment.

Animals—15 healthy Beagles.

Procedures—Dogs were randomly assigned to 3 treatment groups (n = 5/group): 38-hour IV infusion of saline (0.9% NaCl) solution (control group), saline solution with 8.5% amino acids (2.3 g/kg/d), or saline solution with 8.5% amino acids (1.8 g/kg/d) and 20% l-alanyl-l-glutamine (Ala-Gln; 0.5 g/kg/d). High-dose MPSS treatment was initiated at the same time that IV infusions began, such that a total dose of 85 mg of MPSS/kg was administered through multiple IV injections over a 26-hour period. The infusions were maintained until 12 hours after the last MPSS injection. Blood samples collected before MPSS injections began and 2, 12, and 24 hours after injections ceased were used to evaluate PMN function.

Results—MPSS injections resulted in an increase in the total number of circulating leukocytes and increases in neutrophil and monocyte counts but did not affect lymphocyte, eosinophil, or basophil counts. Lymphocyte counts in the Ala-Gln group were higher than in the control group 12 hours after MPSS injections finished. Relative to preinfusion values, phagocytic capacity, oxidative burst activity, and filamentous actin polymerization of PMNs were suppressed in all dogs except those that received Ala-Gln.

Conclusions and Clinical Relevance—Parenteral Ala-Gln administration in dogs resulted in an increase in PMN phagocytic responses that were suppressed by high-dose MPSS treatment.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether the method of lipopolysaccharide (LPS) administration (intermittent vs continuous) affects the magnitude and duration of the systemic inflammatory response in horses and whether prolonged (48 hours) endotoxemia induces laminitis.

Animals—12 healthy adult horses (10 mares and 2 geldings).

Procedures—Horses were randomly assigned to receive LPS (total dose, 80 μg; n = 4) or saline (0.9% NaCl) solution (80 mL/h; 4) via constant rate infusion or 8 bolus IV injections of LPS (10 μg, q 6 h;4) during a 48-hour period. Physical examinations were performed every 4 hours, inflammatory cytokine gene expression was determined for blood samples obtained every 8 hours, and IV glucose tolerance tests were performed.

Results—All LPS-treated horses had signs of depression and mild colic; those signs abated as the study progressed. Administration of LPS increased expression of interleukin-1β, interleukin-6, and interleukin-8, but results were not significantly different between LPS treatment groups. Cytokine expression was significantly higher on the first day versus the second day of LPS treatment. Interleukin-1β expression was positively correlated with rectal temperature and expression of other cytokines. Glucose and insulin dynamics for both LPS groups combined did not differ significantly from those of the saline solution group. Signs of laminitis were not detected in any of the horses.

Conclusions and Clinical Relevance—Horses developed LPS tolerance within approximately 24 hours after administration was started, and the method of LPS administration did not affect the magnitude or duration of systemic inflammation. Laminitis was not induced in horses.

Full access
in American Journal of Veterinary Research