Effects of high intensity exhaustive exercise on SOD, MDA, and NO levels in rats with knee osteoarthritis

The aim of this study was to investigate the impact of high intensity exhaustive exercise on nitric oxide (NO), malondialdehyde (MDA), and superoxide dismutase (SOD) expression in rats with knee osteoarthritis. Sprague Dawley rats were randomly divided into control (N = 5) and model (N = 35) groups; the model group was further divided into quiet (N = 5), low- (N = 15) and high- (N = 15) intensity exhaustive exercise groups. The low- and high-intensity groups were randomly divided into pre-exercise (N = 5), immediate post-exercise (N = 5), and 24-h post-exercise (N = 5) groups according to different time points for detection. NO, MDA, and SOD levels were compared between each group. The SOD levels in the quiet, low-, and high-intensity exhaustive exercise groups were lower than that in the control group, whereas the NO and MDA levels were higher in the former groups than in the controls (P < 0.05). The SOD level in the 24-h post-low intensity exhaustive exercise group was higher than that in the 24-h post-high intensity exhaustive exercise group, whereas the NO and MDA levels were lower in the 24-h post-low intensity than in the post-high intensity exercise group (P < 0.05). Overall, the results demonstrated that with the increase of exercise intensity, the SOD activity in the rats with knee osteoarthritis decreased gradually, whereas the MDA and NO levels gradually increased. Thus, the greater the exercise intensity, the more serious the impact on knee osteoarthritis.