Exercise has been shown to be beneficial to the skeleton, in both humans and animals. This study was done to test the sex-related difference in the risk of osteoarthritis (OA) of the knee joint and also on the subchondral bone after moderate running exercise.
Forty male and female Wistar rats were randomly assigned to four equal groups (2 male and 2 female groups) in the same condition. Ten animals of each sex were selected as control groups, while running exercises were performed in remaining 20 male and female rats, using a motor treadmill to motivate rats to run daily distances of 1 km at 5 days/week within 6 weeks. On day 43, all animals were sacrificed and the knee articular cartilage and also histomorphometric parameters of subchondral bone and mid shaft of tibia were evaluated.
Results showed mild OA in both male and female runner groups. Results in male runner rats were significantly lesser than that in female runners. On the other hand, the difference in female runner group showed significant changes in comparison with other groups in histomorphometric parameters in tibia.
Obtained results showed that the development of knee OA and subchondral bone changes may be related to the sex differences. Although there was no synovitis in male runners, female runner group showed mild hyperaemia dropsy with a moderate synovitis in this region.