Synovial fluid chondroitin sulphate epitopes 3B3 and 7D4, and glycosaminoglycan in human knee osteoarthritis after exercise

Objective-Walking exercise alleviates some symptoms, such as pain, in patie nts with mild to moderate knee osteoarthritis (OA). However, a major concer n is that weightbearing exercise on osteoarthritic joints may exacerbate ar ticular cartilage degradation. Loading of proteoglycan depleted articular c artilage in vitro increased expression of the chondroitin sulphate epitope 3B3, suggesting that loading may influence metabolism of osteoarthritic car tilage. This study aimed at evaluating the effects of walking exercise on a rticular cartilage metabolism in patients with knee OA, as reflected by cha nges in concentrations of synovial fluid markers. Methods-Thirty elderly patients with knee OA (Kellgren-Lawrence grades II t o IV) were randomly allocated to control (n = 15) and 12 week exercise (n = 15) groups. Synovial fluid obtained from 21 of the patients at time zero a nd after 12 weeks was examined by enzyme linked immuno-sorbent assay (ELISA ) for the chondroitin sulphate epitopes 3B3 and 7D4, and by a dye binding a ssay with 1,9-dimethylmethylene blue for total sulphated glycosaminoglycan (GAG) concentrations. The 3B3/GAG and 7D4/GAG ratios were calculated. Results-No significant changes in concentrations of 3B3, 704, GAG, 3B3/GAG, or 7D4/GAG between time zero and 12 weeks were found in either group. Howe ver, there were significant declines in 3B3 (p=0.001), GAG (p=0.007), and t he 3B3/GAG ratio (p=0.049) with aging. Conclusion-Twelve weeks of walking exercise had no demonstrable adverse eff ects on articular cartilage metabolism, as reflected by the concentrations of synovial fluid GAG or the chondroitin sulphate epitopes 3B3 and 7D4.