The influence of exercise on joint homeostasis in the Shetland pony

Abstract

Reasons for preforming the study Osteoarthritis is a very common problem in the horse, so the increase in its need for early diagnosis has led to the search for potential biomarkers in the joint. If the levels of such biomarkers are interpreted, it is important to know if they are influenced by exercise. Therefore, this study is preformed, to be able to compare these biomarker concentrations later with a study with induced osteoarthritis during the same exercise protocol.

Objective Investigating the influence of exercise on joint homeostasis in the Shetland pony, reflected by catabolic, anabolic, inflammatory and cartilage breakdown biomarkers.

Method Synovial fluid was collected from the left and right inter carpal joint of seven healthy adult Shetland ponies, which were free of lameness and had clinically normal carpal joints. Ponies were subjected to an exercise protocol that consisted of 5 weeks of treadmill training and 5 a week wash-out period. At certain time points, synovial fluid was collected and stored. After the last collection, catabolic markers (C2C and GAG), anabolic markers (CPII), inflammatory markers (CCL2 and PGE2) and cartilage breakdown markers (MMP) were evaluated.

Results The exercise protocol caused a significant increase in CPII concentrations only. In MMP, CCL2 and PGE2 an effect of repeated arthrocentesis was detected.

Conclusions CPII concentrations are affected by exercise and C2C, GAG, CCL-2, PGE2 and MMP concentrations are not. There is a significant increase in CPII concentration, indicating that the anabolic component in the joint homeostasis is increased after the exercise protocol. This study involved repeated arthrocentesis, which is visible in MMP, CCL2 and PGE2 concentrations.

Potential relevance Exercise effects on these biomarker levels will presumably not interfere with effects caused by chondral defects in the up-coming defect-study, except for CPII. These biomarkers could help with the differentiation between the effects of exercise and the effects of exercise plus a defect. However, care should be taken to exclude outcomes affected by interventions such as repeated arthrocentesis.