The lipopolysaccharide model for the experimental induction of transient lameness and synovitis in Standardbred horses

An established lipopolysaccharide (LPS) model previously described in Warmbloods, was inconsistent Standardbred horses, where lameness not detected despite the presence of synovitis. The present study aimed to determine dose LPS from E. coli O55:B5 required induce mild moderate following middle carpal joint injection horses and quantitate induced over time, with without anti-inflammatory pre-treatment. In a baseline trial, eight healthy, clinically sound were used rule-based dose-escalation design starting at 10 endotoxin units (EU). Lameness trot evaluated visually quantitatively (using an inertial-sensor system pressure plate analysis). Synovial fluid aspirates analysed for total nucleated cell counts, protein prostaglandin E2 (PGE2). Following 2 months wash-out, effective LPS-dose determined trial evaluate effect treatment. A mixed repeated measures horse as random analysis. After EU LPS, desired degree observed maximal post-injection hour (PIH) 4, followed by rapid decline return PIH 48. No pre-treatment meloxicam. synovial fluid, PGE2 significantly higher 8 24 compared meloxicam conclusion, consistently induces transient synovitis horses.