Pathological effects of joint stress imbalance on joint tissues

Objective This study aims to determine the pathological effects of joint stress imbalance on joint tissues from multiple mouse models, and provide useful information for clinicians to develop new strategies for the treatment and prevention of Osteoarthritis (OA). Methods In this study, knee joint samples were collected at 2, 4 and 8 weeks, respectively, through the established mouse knee joint long-term fixation model, weight-bearing model and excessive exercise model. The pathological changes of knee joint cartilage, synovial inflammation and osteophytes were observed by Micro-CT and histological staining. Results We found that long-term joint fixation resulted in significant pain, articular cartilage damage, synovial infiltration, and cartilaginous osteophyte of knee joints in mice, and the joint injury became more serious with the extension of fixation time. OA cartilage damage also occurs on the non-fixation weight-bearing side, and the cartilage damage becomes more severe with the extension of weight-bearing time, but it did not cause synovial inflammation and osteophyte formation. However, long-term excessive exercise in mice did not lead to obvious OA lesions such as cartilage damage, synovial inflammation and osteophyte formation, but it increases pain sensitivity. Conclusions This study can provide theoretical guidance for postoperative rehabilitation or exercise in clinical patients: the pathological process of tissue repair and OA lesions should be balanced as much as possible, and the joint fixation time should be shortened to reduce the occurrence of OA. For those who do not have meniscus lesions, moderate exercise can be performed to promote cartilage function, while for those with meniscus lesions or long-term weight bearing, joint movement should be reduced to repair meniscus lesions or reduce weight bearing to reduce the occurrence of OA.