Effects of Treadmill Exercise and Swimming on Spontaneous Developed Knee Osteoarthritis in Senescence-accelerated Mouse Prone 8

Abstract

This study investigated the effects of treadmill exercise and swimming on spontaneous developed knee osteoarthritis in the senescence-accelerated mouse prone 8 (SAMP8). Twenty-two weeks old SAMP8 mice were randomly divided into the No-exercise group, treadmill exercise group, and swimming group (n = 6 in each group). Treadmill exercise was performed at the speed of 10-12 m/min, and swimming was performed at a water temperature of 37-38℃ for 15 min/day, 5 day a week for 6 weeks. After exercise intervention, we examined the knee joint angle, width of the knee joint, stride length, and knee joint histological changes. Comparison with No-exercise group, both exercise groups were improved the knee joint angle and stride length. In addition, increased type II collagen positive chondrocyte, reduced matrix metalloproteinase (MMP)-13 positive chondrocyte, and tumor necrosis factor (TNF)-α positive cells in the synovium were observed in both exercise groups. Notably, the swimming group significantly improved the stride length and increased the ratio of type II collagen positive chondrocyte that is important protein maintaining a chondrocyte homeostasis. This study suggested that both exercise regimens alleviate age-related OA alteration, which improved the knee joint angle and stride length. The swimming may be beneficial in maintaining homeostasis for age-related OA joint and improving age-related gait disturbance.