Effect of Moderate Treadmill Exercise on hip Osteoarthritis in Male and Female Wistar Rats

Background: Osteoarthritis (OA) is a slowly progressive degenerative disease characterized by gradual loss of articular cartilage. The influence of excessive running load on the development of knee OA was investigated in male Wistar rats. This study was done to test the sex-related difference in the risk of OA of the hip joint after moderate running exercise. Materials and Methods: Forty male and female Wistar rats were randomly assigned to four equal groups (2 male and 2 female groups) in a same condition. Ten of each sex were selected as control groups and kept separately while running exercises were performed in remained 20 male and female rats using a motor treadmill to motivate rats to run daily distances of 1 km at 5 days/week within six weeks. The treadmill incline was zero. On day 43, all control and training animals were killed and the hip articular cartilage and its synovial layer were evaluated microscopically. Results: The appearance of hip articular cartilage was normal and similar in all male, female and also male running groups while female running group showed some changes. Obtained results showed a mild OA only in the female running group. There wasn‟t seen synovitis in both male and female running groups in comparison with control groups (P>0.05). Conclusion: This study showed that the development of hip OA may be related to the sex differences as seen in the knee OA previously.