Search Results

Abstract

Objective—To determine response of interleukin-1α (IL-1α)-conditioned equine articular cartilage explants to insulin-like growth factor-1 (IGF-1).

Sample Population—Cartilage from the trochlea and condyles of the femur of a clinically normal 4-year-old horse.

Procedure—Effects of IGF-1 (0 to 500 ng/ml) after addition of IL-1α were evaluated by assessing matrix responses, using a sulfated glycosaminoglycan (GAG) assay, matrix ³⁵SO₄ GAG incorporation, and release of GAG. Mitogenic response was assessed by ³H-thymidine incorporation into DNA and fluorometric assay of total DNA concentration.

Results—Human recombinant IL-1α (40 ng/ml) increased the amount of labeled GAG released and decreased labeled and total GAG remaining in explants, and IL-1α decreased mitogenic response. Addition of IGF-1 counteracted effects seen with IL-1α alone. In general, IGF-1 decreased total and labeled GAG released into the medium, compared with IL-1α- treated explants (positive-control sample). Values for these variables did not differ significantly from those for negative-control explants. A significant increase in total and newly synthesized GAG in the explants at termination of the experiment was observed with 500 ng of IGF-1/ml. Labeled GAG remaining in explants was greater with treatment at 50 ng of IGF-1/ml, compared with treatment with IL-1α alone. Concentrations of 200 ng of IGF-1/ml abolished actions of IL-1α and restored DNA synthesis to values similar to those of negative-control explants.

Conclusions and Clinical Relevance—IGF-1 at 500 ng/ml was best at overcoming detrimental effects associated with IL-1α in in vitro explants. These beneficial effects may be useful in horses with osteoarthritis. (Am J Vet Res 2000;61:436–441)

Abstract

Objective—To determine relative amounts of mRNA expression of aggrecan, type-II collagen, matrix metalloproteinase (MMP) 1, and MMP3 in articular cartilage and synovial membrane samples from healthy equine joints and joints with osteoarthritis (OA) and to compare results of Northern blot hybridization with results of a reverse transcriptase-polymerase chain reaction (RT-PCR) assay.

Sample Population—Articular cartilage samples from 8 pairs of joints (1 with OA and 1 healthy) from 6 horses and synovial membrane samples from 6 pairs of joints from 5 horses.

Procedure—RNA was extracted from samples by use of a modified Trizol procedure. Northern blot hybridization and the RT-PCR assay were performed; results were quantitated by use of glyceraldehyde 3- phosphate dehydrogenase as an internal standard.

Results—Articular cartilage samples from joints with mild or moderate OA yielded less total RNA than samples from joints with severe OA. Northern blot hybridization indicated that type-II collagen mRNA expression in articular cartilage samples from joints with OA was significantly greater than expression in samples from healthy joints. The RT-PCR assay identified low levels of MMP3 mRNA expression in 4 of 8 sets of articular cartilage samples and 4 of 6 sets of synovial membrane samples, whereas Northern blot hybridization identified MMP3 mRNA expression in only 1 of 6 sets of articular cartilage samples and 1 of 6 sets of synovial membrane samples.

Conclusions—A RT-PCR assay is more sensitive than Northern blot hybridization for detection of MMP3 mRNA expression in articular cartilage and synovial membrane and requires smaller samples. (Am J Vet Res 2000;61:900–905)

Abstract

Objective—To determine the clinical applications, short and long-term survival, and complications of using transfixation pin casts for treatment of comminuted phalangeal fractures in adult horses.

Design—Retrospective case series.

Animals—20 horses.

Procedures—Medical records were reviewed to obtain information regarding signalment, fracture location, treatment methods, complications, and short-term survival (discharge from hospital). Long-term follow-up information was obtained via contact with owners or trainers.

Results—12 fractures were in a hind limb, and 8 were in a forelimb. Fourteen fractures occurred in a middle phalanx, and 6 occurred in a proximal phalanx. Eleven fractures were treated with internal fixation combined with transfixation pin casts, and 9 fractures were treated with transfixation pin casts alone. Transfixation pin casts were maintained for a mean of 52 days (median, 49 days; range, 1 to 131 days). Fourteen (70%) horses were discharged from the hospital, whereas 6 (30%) were euthanized during the treatment period. Reasons for euthanasia included secondary fracture of the third metacarpal or metatarsal bone, avascularity of the distal aspect of the limb associated with an open fracture, and displacement of the fracture after transfixation pin cast removal. A significantly greater number of horses was discharged from the hospital when the transfixation pin cast was maintained for > 40 days, compared with those in which the transfixation pin cast was maintained for < 40 days.

Conclusions and Clinical Relevance—Results suggested that horses should be maintained in a transfixation pin cast for a minimum of 40 days, as this was associated with an increase in short-term survival without an increased risk of catastrophic failure.

Abstract

Objective—To evaluate the outcome of horses with large fragments of the extensor process of the distal phalanx that were removed by use of arthrotomy.

Design—Retrospective study.

Animals—14 horses with large fragments of the extensor process of the distal phalanx.

Procedure—Medical records for horses with large fragments of the extensor process that were removed by use of arthrotomy were reviewed. Data retrieved from medical records included signalment, use of horse, affected limb, lameness history, lameness examination findings, radiographic findings, surgical technique, and outcome. Follow-up evaluation was obtained by telephone interview.

Results—Most affected horses were < 5 years old and had a history of chronic lameness. Lameness grade ranged from 1/5 to 4/5. Fragments involved 20 to 45% of the dorsopalmar articular surface of the distal phalanx. Eight of 14 horses had a successful outcome. Outcome was not associated with age, duration or severity of lameness, or fragment size.

Conclusions and Clinical Relevance—Despite involvement of a large portion of the articular surface and use of arthrotomy, joint instability and permanent soft tissue injury was not a problem in most horses. Outcome may be improved by selection of horses with lameness of < 2 years' duration and careful management after surgery. A fair prognosis may be anticipated for removal of large fragments of the extensor process via arthrotomy. (J Am Vet Med Assoc 2000; 217:1351–1355)

Abstract

Objectives—To determine concentrations of matrix metalloproteinase (MMP)-2 and -9 in synovial fluid; and mRNA expression of MMP-1, -13, and -3; interleukin[ IL]-1α and β; and tumor necrosis factor(TNF)-α in synovial membrane and articular cartilage from horses with naturally occurring joint disease.

Sample Population—Synovial fluid (n = 76), synovial membrane (59), and articular cartilage (45) from 5 clinically normal horses and 55 horses with joint disease categorized as traumatic (acute [AT] or chronic [CT]), osteochondritis dissecans (OCD), or septic (S).

Procedure—Synovial fluid gelatinase concentrations were analyzed, using zymography. Synovial membrane and articular cartilage mRNA expression for MMP-1, -3, and -13, IL-1α and β, TNF-α, type-II collagen, and aggrecan were analyzed, using quantitative reverse transcriptase-polymerase chain reaction.

Results—Synovial fluid pro-MMP-2 concentration was significantly higher in diseased joints than normal joints. Septic joints had significantly higher concentrations of pro and active MMP-9. Stromelysin-1 was expressed in ≥ 80% of synovial membrane and articular cartilage samples and was strongly influenced by age. Collagenases were rarely expressed, with MMP- 13 expressed only in diseased joints. Interleukin-1β expression was significantly higher in all OCD samples and was influenced by age. Tumor necrosis factor- α expression was significantly higher in cartilage from joints with AT and OCD. There was no correlation between MMP or cytokines and type-II collagen or aggrecan expression.

Conclusions and Clinical Relevance—Matrix metalloproteinase- 2 and -3 are abundant in naturally occurring joint disease and normal joints. Interleukin-1β and TNF-α may be important in the pathogenesis of OCD. Age affects MMP and IL-1β concentrations. (Am J Vet Res 2001;62:1467–1477)

Abstract

Objective—To assess the long-term clinical outcome of horses with distal tarsal osteoarthritis (OA) in which a 3-drill-tract technique was used to induce arthrodesis of the affected joints, identify any preoperative or operative factors associated with outcome, and describe any complications associated with the technique.

Design—Retrospective study.

Animals—54 horses.

Procedure—Medical records were reviewed for information on signalment, use, history, physical and lameness examination findings, surgical technique, and postoperative care. Radiographs were examined, and severity of OA was graded. Follow-up information was obtained through telephone interviews with owners at least 13 months after the procedure.

Results—32 (59%) horses had a successful outcome, 6 (11%) improved but were not sound after surgery, and 16 (30%) did not improve following surgery. Outcome was negatively associated with the previous use of intra-articular injections. Few postoperative complications were evident.

Conclusions and Clinical Relevance—Results suggest that distal tarsal OA in horses can be successfully treated by means of distal tarsal arthrodesis with a 3-drill-tract technique. Horses with advanced distal tarsal OA are likely to have poorer outcomes, and the procedure will likely be of minimal benefit in horses with concomitant causes of hind limb lameness prior to surgery and in horses with preexisting proximal intertarsal joint disease. (J Am Vet Med Assoc 2003; 223;1800–1805)