The role of MiR-143-3p in swimming exercise protection against osteoarthritis in mice.

Objective: This study aimed to investigate the effects of swimming exercise on cartilage, inflammatory markers, subchondral bone structure, and stride length in mice with knee osteoarthritis induced by anterior cruciate ligament (ACL) transection, and to explore the role of miR-143-3p in these effects.

Methods: Thirty-six 3-month-old male C57BL/6 mice were randomly divided into three groups: control, exercise (swimming 30 min daily for one month), and exercise + miR-143-3p mimics (swimming exercise plus intra-articular injection of miR-143-3p mimics lentivirus once every two weeks for four weeks). Experimental groups underwent ACL transection to induce osteoarthritis. Interventions began two weeks post-modeling. Post-intervention, stride length analysis, histological analysis (including assessment of cartilage morphology and chondrocyte number), and micro-CT scanning (to assess subchondral bone structure) were performed. Inflammatory markers were measured in cartilage.

Results: Swimming exercise partially alleviated joint inflammation (as evidenced by reduced levels of IL-1β), protected cartilage (maintaining chondrocyte number and extracellular matrix homeostasis, as demonstrated by improved cartilage morphology), and enhanced subchondral bone structure. However, miR-143-3p supplementation partially inhibited these beneficial effects of swimming exercise. Both exercise groups showed gait impairment (reduced stride length) compared to controls, with no significant difference between the two exercise groups.

Conclusion: Swimming exercise can mitigate osteoarthritis progression by protecting cartilage, improving subchondral bone structure, and reducing inflammation. However, miR-143-3p partially counteracts these protective effects.