Effects of Well-Rounded Exercise Training on Cartilage Metabolism in Females without Radiologically Knee Osteoarthritis

Abstract

PURPOSE: The population with osteoarthritis (OA) is increasing due to the aging society. Maintenance of healthy cartilage is essential for prevention of OA. Physical exercise is highly recommended for OA patients because of clear evidence that it reduces pain and enhances physical function of joints with OA. For older adults, exercise prescription ideally includes aerobic, muscle strengthening, and flexibility exercises. However, effects of the exercise intervention on preosteoarthritic cartilage remain unclear. This study was aimed to evaluate the effects of well-rounded exercise training on cartilage metabolism using systemic biomarkers in females without radiologically knee OA. METHODS: A combination of aerobic, resistance (mainly for quadriceps and hamstrings), flexibility, and balance exercise trainings was assigned to 23 female subjects [mean age 57.9 (49 to 68), mean BMI 21.8 (18.6 to24.7)] without radiologically knee OA (Kellgren-Lawrence grade≤1) for 90 minutes once a week during 12 weeks under supervision. The subjects were followed up during the subsequent 12 weeks. Blood and urine samples were collected at 0, 1, 2, 4, 8, 12, 16, 20, and 24 weeks from the initiation of intervention. Whereas type II collagen carboxy-propeptide (CPII) and cartilage oligomeric matrix protein (COMP) were measured using serum by enzyme-linked immunosorbent assay (ELISA), collagenase-generated neoepitope of type II collagen (C2C) and carboxy-telopeptide of type II collagen (CTX-II) were evaluated using urine by ELISA. RESULTS: One week after the initiation of the training, type II collage degradation evaluated by CTX-II dropped down to lower levels, and thereafter maintained the levels by the final follow-up. Compared with the baseline, a significant decrease in CTX-II levels was found at 1, 2, 4, 8, and 24 weeks. Similarly, type II collage cleavage evaluated by C2C reduced immediately after the exercise intervention, and reached the significantly low levels at 12, 20, and 24 weeks. Type II collagen synthesis evaluated by CPII and a cartilage degradation marker COMP had no appreciable changes during the whole period of intervention and the subsequent follow-up. CONCLUSIONS: Well-rounded exercise training could decrease type II collagen degradation in females without radiologically knee OA.