The Expression of IL-1, IL-6, and TGF-β in the Synovial Fluid of Horses with Surgically-Induced Transient Synovitis

Abstract

SummaryThis study investigates the presence of various cytokines in the synovial fluid of three horses with surgicallyinduced synovitis in one antebrachiocarpal joint. Synovial fluids were sampled from experimental and control joints, preoperatively and at two and 30 days post-operatively. Samples were analyzed for interleukin-1 and interleukin- 6 bioactivities with a bioassay, and for transforming growth factor-beta protein by ELISA. Peak cytokine levels were detected on day two post-synovectomy, and returned to pre-operative levels by 30 days post-synovectomy (Interleukin-6 in treated joints: day #0; 0.53 ±0.2, day #2; 9.8 ± 0.7, day #30; 0.4 ± 0.2. Transforming growth factorbeta in treated joints: day #0; 314 ± 69, day #2; 1101 ± 325, day #30; 321 ± 101). Arthrocentesis alone (i.e. control joints) caused no increase in interleukin- 1, interleukin-6 and transforming growth factor-beta levels. Interleukin-1 and interleukin-6 are thought to both prevent anabolic and enhance catabolic effects within articular cartilage matrices, whereas it has been proposed that transforming growth factor-beta may have a protective effect on the articular cartilage. This study is the first to document elevated transforming growth factor-beta levels in equine joints.This study documents elevated levels of transforming growth factor-beta, interleukin-1 and interleukin-6 in the joints of horses with surgically-induced transient synovitis.