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Abstract

Objective—To evaluate the temporal pattern of prostaglandin (PG) E2 concentrations in synovial fluid after transection of the cranial cruciate ligament (CCL) in dogs and to correlate PGE2 concentrations with ground reaction forces and subjective clinical variables for lameness or pain.

Animals—19 purpose-bred adult male Walker Hounds.

Procedure—Force plate measurements, subjective clinical analysis of pain or lameness, and samples of synovial fluid were obtained before (baseline) and at various time points after arthroscopic transection of the right CCL. Concentrations of PGE2 were measured in synovial fluid samples, and the PGE2 concentrations were correlated with ground reaction forces and clinical variables.

Results—The PGE2 concentration increased significantly above the baseline value throughout the entire study, peaking 14 days after transection. Peak vertical force and vertical impulse significantly decreased by day 14 after transection, followed by an increase over time without returning to baseline values. All clinical variables (eg, lameness, degree of weight bearing, joint extension, cumulative pain score, effusion score, and total protein content of synovial fluid, except for WBC count in synovial fluid) increased significantly above baseline values. Significant negative correlations were detected between PGE2 concentrations and peak vertical force (r, –0.5720) and vertical impulse (r, –0.4618), and significant positive correlations were detected between PGE2 concentrations and the subjective lameness score (r, 0.5016) and effusion score (r, 0.6817).

Conclusions and Clinical Relevance—Assessment of the acute inflammatory process by measurement of PGE2 concentrations in synovial fluid may be correlated with the amount of pain or lameness in dogs. (Am J Vet Res 2004;65:1269–1275)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether decreases in peak vertical force of the hind limb after transection of the cranial cruciate ligament (CrCL) would be indicative of medial meniscal damage in dogs.

Animals—39 purpose-bred adult male Walker Hounds.

Procedure—The right CrCL was transected arthroscopically. Force plate measurements of the right hind limb were made prior to and 2, 4, 10, and 18 weeks after transection of the CrCL. Only dogs with ≥ 10% decreases in peak vertical force after week 2 were considered to have potential meniscal damage. Dogs that did not have ≥ 10% decreases in peak vertical force at any time point after week 2 were assigned to group 1. Group 2 dogs had ≥ 10% decreases in peak vertical force from weeks 2 to 4 only. Group 3 and 4 dogs had ≥ 10% decreases in peak vertical force from weeks 4 to 10 only or from weeks 10 to 18 only, respectively. Damage to menisci and articular cartilage was graded at week 18, and grades for groups 2 to 4 were compared with those of group 1.

Results—The percentage change in peak vertical force and impulse area was significantly different in groups 2 (n = 4), 3 (4), and 4 (4) at the end of each measurement period (weeks 4, 10, and 18, respectively) than in group 1 (27). The meniscal grade for groups 2 to 4 was significantly higher than for group 1. A ≥ 10% decrease in peak vertical force had sensitivity of 52% and accuracy of 72% for identifying dogs with moderate to severe medial meniscal damage.

Conclusions and Clinical Relevance—In dogs with transected or ruptured CrCLs, force plate analysis can detect acute exacerbation of lameness, which may be the result of secondary meniscal damage, and provide an objective noninvasive technique that delineates the temporal pattern of medial meniscal injury. ( Am J Vet Res 2005;66:156–163)

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in American Journal of Veterinary Research

Abstract

Objective—To compare articular cartilage from horses with naturally developing osteochondrosis (OC) with normal articular cartilage and healing cartilage obtained from horses with experimentally induced osteochondral fractures.

Sample Population—109 specimens of articular cartilage from 78 horses.

Procedure—Morphologic characteristics, proteoglycan (PG), and type II collagen were analyzed in articular cartilage of OC specimens (group 1), matched healing cartilage obtained 40 days after experimentally induced osteochondral fractures (group 2), and matched normal cartilage from the same sites (group 3).

Results—79 specimens of OC cartilage were obtained from horses. Ex vivo PG synthesis was significantly greater in the femoral cartilage, compared with synthesis in the tibial cartilage, and significantly greater for groups 1 and 2, compared with group 3. For groups 1 and 2, femoral fragments had significantly greater PG content, compared with PG content in tibial fragments. Keratan sulfate content was significantly less in group 3, compared with groups 1 and 2. Cartilage from the OC specimens had loss of structural architecture. The OC tissue bed stained positive for chondroitin sulfate and type II collagen, but the fracture bed did not.

Conclusions and Clinical Relevance—Our analyses could not distinguish articular cartilage from horses with OC and a healing fracture. Both resembled an anabolic, reparative process. Immunohistochemical analysis suggested a chondromyxoid tissue in the OC bed that was morphologically similar to fibrous tissue but phenotypically resembled hyaline cartilage. Thus, tissue in the OC bed may be degenerative cartilage, whereas tissue in the fracture bed may be reparative fibrous callus. (Am J Vet Res 2005;66:1881–1890)

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in American Journal of Veterinary Research

Abstract

Objective—To assess clinical, radiographic, histologic, and biochemical effects of sodium pentosan polysulfate (NaPPS) administered IM for treatment of experimentally induced osteoarthritis in horses.

Animals—18 horses.

Procedures—Osteoarthritis was induced arthroscopically in 1 middle carpal joint of all horses. Nine horses received NaPPS (3 mg/kg, IM) on study days 15, 22, 29, and 36. Nine control horses received the same volume of saline (0.9% NaCl) solution IM on study days 15, 22, 29, and 36. Clinical, radiographic, gross, histologic, histochemical, and biochemical findings as well as findings of synovial fluid analysis were evaluated.

Results—No adverse treatment-related events were detected. Induced osteoarthritis caused a substantial increase in lameness, response to flexion, joint effusion, radiographic findings, synovial membrane inflammation, and articular cartilage fibrillation. Articular cartilage fibrillation was substantially reduced by NaPPS treatment, and concentrations of chondroitin sulfate 846 epitope were significantly increased in the synovial fluid of osteoarthritic and nonosteoarthritic joints of treated horses.

Conclusions and Clinical Relevance—Results indicated that NaPPS has some beneficial disease-modifying effects and may be a therapeutic option for osteoarthritis in horses.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To evaluate the efficacy of IV administration of a product containing hyaluronan, sodium chondroitin sulfate, and N-acetyl-d-glucosamine for prevention or treatment of osteoarthritis in horses.

ANIMALS 32 healthy 2- to 5-year-old horses.

PROCEDURES The study involved 2 portions. To evaluate prophylactic efficacy of the test product, horses received 5 mL of the product (n = 8) or saline (0.9% NaCl) solution (8; placebo) IV every fifth day, starting on day 0 (when osteoarthritis was induced in the middle carpal joint of 1 forelimb) and ending on day 70. To evaluate treatment efficacy, horses received either the product or placebo (n = 8/treatment) on days 16, 23, 30, 37, and 44 after osteoarthritis induction. Clinical, diagnostic imaging, synovial fluid, gross anatomic, and histologic evaluations and other tests were performed. Results of each study portion were compared between treatment groups.

RESULTS Limb flexion and radiographic findings were significantly worse for horses that received the test product in the prophylactic efficacy portion than for placebo-treated horses or product-treated horses in the treatment efficacy portion. In the prophylactic efficacy portion, significantly less articular cartilage erosion was identified in product-treated versus placebo-treated horses. In the treatment efficacy portion, joints of product-treated horses had a greater degree of bone edema identified via MRI than did joints of placebo-treated horses but fewer microscopic articular cartilage abnormalities.

CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that caution should be used when administering the evaluated product IV to horses, particularly when administering it prophylactically, as it may have no benefit or may even cause harm.

Full access
in American Journal of Veterinary Research

SUMMARY

Articular cartilage specimens from the distal articular surface of 32 radiocarpal bones from 24 2- to 5-year-old horses were analyzed. The total collagen content was determined on the basis of the 4-hydroxyproline content, using a colorimetric method. A method for estimating the proportions of types-I and -II collagen by measuring spectrophotometric densities of specific cyanogen bromide peptide bands from mixtures of types-I and -II collagen on sodium dodecyl sulfate-polyacrylamide gels was used. The cyanogen bromide peptides representative of each collagen types-I and -II were identified. The peptide ratios were then computed for each of several standards of type-I and -II mixtures. A standard curve was derived from the correlation between these ratios and the corresponding proportions of type-II collagen in standard mixtures. Galactosamine and glucosamine content (hexosamines) were measured by ion chromatography. The galactosamine-to-glucosamine ratio, chondroitin sulfate and keratan sulfate values, and total glycosaminoglycan content were derived from the measured hexosamine content.

The total collagen content averaged 556 mg/g (55.6 mg/100 mg) of tissue (dry weight, [dw]). Type-II collagen was the major collagen type in normal articular cartilage specimens. The ratio of the area under the αl (II)CBIO peak to the area under the αl (I)CB 7,8 + αl (II)CB11 peak was a second-order polynomial function of the proportion of type-II collagen in the specimens. The mean galactosamine and glucosamine content were 20.6 mg/g and 7.9 mg/g (dw), respectively. The mean galactosamine-to-glucosamine ratio was 3.74 ± 0.62. Chondroitin sulfate values, keratan sulfate values, and total glycosaminoglycan content were 53.3 ± 4.9 mg/g, 19.9 ± 3.6 mg/g, and 73.2 ± 7.9 mg/g (dw), respectively. There was no significant correlation between the age of the horses and any of the chemical values (P > 0.1). The biochemical composition of articular cartilage in the horse is similar to that of other species.

Free access
in American Journal of Veterinary Research

Abstract

Objectives

To clone equine interleukin 1 receptor antagonist (IL-1 ra) and determine its full-length cDNA sequence.

Procedure

A cDNA library derived from lipopolysaccharide-stimulated equine monocytes was screened by means of plaque hybridization to radiolabeled equine IL-1ra DNA probes generated by means of the polymerase chain reaction. The cDNA nucleotide sequence for equine IL-1ra was determined by use of the dideoxy chain termination technique, analyzed by use of computer software for sequence characteristics, and compared with sequences reported for IL-1ra of other species.

Results

The cDNA for equine IL-1ra was 1,614 base pairs in length with an ORF encoding a peptide of 177 amino acids with a predicted molecular mass of 20.427 kd. Similarity between the amino acid sequence of equine IL-1ra and sequences for human, murine, rat, and lapine IL-1ra was 76%. Similarity between sequence for equine IL-1ra and sequences for equine interleukin-1α and equine interleukin-1ß were 22.6 and 24.6%, respectively.

Conclusion

Comparison of the sequence for equine IL-1ra with sequences for IL-1ra of other species indicated a high degree of conservation.

Clinical Relevance

Results establish a basis for studying the roles of interleukin-1 in healthy and diseased joints in horses. (Am J Vet Res 1998;59:712-716)

Free access
in American Journal of Veterinary Research

Abstract

Objectives

To clone equine interleukin 1α (IL-1α) and equine interleukin 1β (IL-1β) and determine their full-length cDNA sequences.

Procedure

The mRNA isolated from lipopolysaccharide-stimulated cultured equine monocytes was reverse transcribed, and a cDNA library was constructed in a λ phage. The cDNA library was screened by means of plaque hybridization with radiolabeled human IL-1α and IL-1ß cDNA probes. The cDNA nucleotide sequences for equine IL-1α and equine IL-1β were determined by use of the dideoxy chain termination technique. The cDNA sequences were analyzed, using computer software, for sequence characteristics and compared with sequences reported for other species.

Results

The cDNA for equine IL-1α was 1,728 base pairs in length with an ORF encoding a peptide of 270 amino acids with a predicted molecular mass of 30.823 kd. The cDNA for equine IL-1β was 1,473 base pairs in length with an ORF encoding a peptide of 268 amino acids with a predicted molecular mass of 30.342 kd. Similarity between amino acid sequence of equine IL- 1α and sequences for IL-1 α of other species ranged from 62.5 to 82.2%; similarity between amino acid sequence of equine IL-1ß and sequences for IL-1β of other species ranged from 62.5 to 66.4%. Similarity between amino acid sequences of equine IL-1α and equine IL-1β was 26%.

Conclusions and Clinical Relevance

Results establish a basis for studying the roles of interleukin 1 in healthy and diseased joints in horses. (Am J Vet Res 1998;59:704-711)

Free access
in American Journal of Veterinary Research

Objective—

To determine the outcome of horses after arthroscopic removal of abaxial fracture fragments of the proximal sesamoid bone and association of fracture grade with outcome.

Design—

Retrospective study.

Animals—

47 horses.

Procedure—

Information obtained from dorsopalmar and dorsoplantar radiographic views of metacarpophalangeal and metatarsophalangeal joints was used to classify fractures as grade 1 (< 15 mm long), grade 2 (15 to 25 mm long), and grade 3 (> 25 mm long) and type 1 (abaxial) and type 2 (apical-abaxial). Outcome was determined by whether the horse returned to its intended use, raced in the same class or higher (racehorses), or performed satisfactorily (nonracehorses). Number of starts, performance index, and money earned were also used to evaluate performance of racehorses.

Results—

Follow-up information was obtained for 41 horses (35 racehorses, 6 nonracehorses). Twenty-five racehorses were able to return to racing (16 in the same class, 9 in a lower class). All 6 nonracehorses were able to return to performance at the same level. Horses with small fracture fragments or fractures involving the abaxial aspect of the proximal sesamoid bone only had a more favorable outcome, compared with horses with large or apical-abaxial fractures.

Clinical Implications—

Overall, horses with abaxial fractures of the proximal sesamoid bone have a favorable prognosis for return to racing, but only a fair prognosis for return to racing in the same class, after arthroscopic removal of fracture fragments. Successful results can be expected for nonracehorses. (J Am Vet Med Assoc 1998:213:1016-1021)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To evaluate the effects of a commercially defined, serum-free medium additive on equine articular cartilage explants, compared with effects of serum-free and serum-supplemented media.

Animals

Articular cartilage from a 3-year-old, mixed breed horse euthanatized for reasons other than musculoskeletal disease or sepsis.

Procedure

Media were changed every 48 hours, and the glycosaminoglycan (GAG) content was determined in media collected at each time point. Glycosaminoglycan synthesis by explant chondrocytes, and residual GAG content of articular cartilage (as a measure of explant GAG loss) were determined at the end of the study (day 8).

Results

Articular cartilage explants in serum-free medium and the commercial supplemented medium had significantly lower GAG synthesis and GAG content than did those incubated in serum-supplemented medium. There were no significant differences in GAG synthesis and content between serum-free and commercial supplemented medium groups. When comparing medium GAG content for all treatment groups, the GAG content in serum-free medium on day 8 was significantly greater than that in commercial supplemented medium, but significant differences were not evident in percentage of release of GAG (as an indicator of GAG degradation) among all 3 treatment groups.

Conclusions

Commercial supplemented medium had effects on articular cartilage matrix GAG loss into medium equal to those of serum-supplemented medium (eg, both lost articular cartilage explant GAG to a similar degree). However, residual articular cartilage GAG content was higher in serum-supplemented medium, as was GAG synthesis. Commercial supplemented medium appears to either lack the proper ingredients to maintain steadystate GAG synthesis, or lacks proper concentrations of these ingredients. (Am J Vet Res 1996;57:1261–1265)

Free access
in American Journal of Veterinary Research