Abstract

Objective: To study the “starting mechanism” and pathological process of knee cartilage injury in different movement training with high intensity. Materials and Methods: 72 New Zealand white rabbits were divided into 3 groups randomly: Untreated Control Group (CTRL, n=8), animals were untreated by any intervention processing; Running Training Group (RG, n=32), animals were trained running in a treadmill daily; Jumping Training Group (JG, n=32), animals were trained jumping in an electric stimulation cage daily. Rabbits in RT and JT were euthanized at 4 week and 8 week respectively, and knee joints were taken out to be examined histologically. GAG content, thickness of cartilage and subchondral bone, dead cell ratio and Mankin grades were measured respectively. Results: By microexaminations, different pathological changes of early sport injury of knee cartilage in RG and JG were found. Animals receiving jumping training displayed a significantly higher degree of grossly and cartilage matrix detectable degeneration on the weight-loading region of the femur condyles than did animals receiving running training; on the contrary, animals receiving running training displayed a significantly higher degree of chondrocyte damage than did animals receiving jumping training in the earlier stage (4-week). Conclusions: Repetitive and high-intensity jumping exercise can do more harm to cartilage matrix than to chondrocyte in knee joint, the pathogenesis displays as “cartilage matrix starting mechanism”; on the contrary, running exercise can do more harm to chondrocyte than to cartilage matrix, the pathogenesis displays as “chondrocyte starting mechanism”. In addition, the difference in pathogenesis and cartilage damage phenotype by different exercises may have a close correlation with the different loading rate of stress on knee cartilage surface. Verf.-Referat