The Effects of Forced Exercise on Collagen Type II Fragments, Lysyl Oxidase Concentrations, and Total Protein Concentrations in Sera and Synovial Fluid of Lambs

Excessive exercise may induce osteoarthritis, which is a leading cause of lameness and decreased use in horses. The purpose of this study was to utilize a sheep model to determine the effects of circular and linear exercise on biochemical markers in serum and synovial fluid (SF). Twenty lambs (5 months) were assigned to three groups: circular exercise (C, 8.5 m diameter; n = 8), straight-line exercise (S, treadmill; n = 8) and nonexercised control (CON, n = 4). Lambs (C and S) were exercised up to 8 weeks at 1.3 m/s for up to 30 minutes, 6 days per week. Serum and SF from a metacarpophalangeal (MCP) joint was collected. Serum total protein (P = .66), Collagen Type II cleavage [3/4] fragments concentrations (P = .44) and lysyl oxidase (LOX) (P = .15) activity were not different among treatment groups throughout the study. There was a polynomial response to serum LOX over time (R2 = 0.7464). There were no differences in SF total protein (P = .94, right MCP; P = .68, left MCP) or SF LOX specific activities (P = .9, right MCP; P = .93, left MCP) among groups throughout the study. However, SF LOX specific activity did increase over time (P = .001) for all treatment groups. These results indicated that the biochemical markers utilized in this study were unable to detect differences between groups with respect to exercise protocols. However, the LOX activity did increase over time possibly as a result of growth.