Effects of intra-articular injections of bufexamac suspension on amphotericin B-induced aseptic arthritis in horses

OBJECTIVE: To evaluate effects of intra-articular (i.a.) injections of bufexamac on amphotericin B-induced aseptic arthritis in horses. ANIMALS: 24 Standardbred horses. PROCEDURE: Aseptic arthritis was induced in the right intercarpal joint by i.a. injection of amphotericin B (20 mg). One week later (day 0), horses were randomly assigned to four 6-horse treatment groups and treated with i.a. injection of 10, 20, or 40 mg of bufexamac suspension (20 mg/ml) or 2.0 ml of sterile saline (0.9% NaCl) solution (control). The treatment was repeated once after 7 days. Clinical lameness examinations and synovial fluid (SF) analyses were done prior to induction and at weekly intervals for 5 weeks (days 0, 7, 14, 21 and 28). RESULTS: Intra-articular injection of amphotericin B consistently resulted in aseptic arthritis with a lameness index (mean +/- SEM; scale 0 to 5) of 2.7 +/- 0.17 on day 0. Intra-articular injections of 20 and 40 mg of bufexamac significantly reduced the day-28 lameness index, compared with control values. Amphotericin B administration also resulted in a significant increase in SF beta-glucuronidase (BGLUC) activity, and i.a. injections of bufexamac significantly reduced day-28 activity of this enzyme, compared with control values. CONCLUSIONS AND CLINICAL RELEVANCE: 2 i.a. injections of 20 or 40 mg of bufexamac, at weekly intervals, were effective in reducing clinical signs of lameness and SF activity of BGLUC associated with amphotericin B-induced carpal joint arthritis. Bufexamac possesses anti-inflammatory properties useful for i.a. treatment of lameness associated with aseptic arthritis in horses.