Traditional Chinese Manual Therapy (Tuina) Improves Knee Osteoarthritis by Regulating Chondrocyte Autophagy and Apoptosis via the PI3K/AKT/mTOR Pathway: An in vivo Rat Experiment and Machine Learning Study.

Background: Knee osteoarthritis (KOA) is on the rise due to lifestyle changes, obesity, and aging, yet effective treatments are lacking. Traditional Chinese manual therapy (Tuina) is promising for KOA. However, its mechanism remains unclear.

Objective: This study aims to determine the effects of Tuina on a rat KOA model, focusing on the role of chondrocyte apoptosis and autophagy mechanisms.

Methods: KOA was induced in rats by intra-articular injection of L-cysteine-activated papain into the right knee. Thirty-six male Sprague Dawley (SD) rats were randomly divided into blank, model control, Tuina, and positive drug groups. Paw withdrawal threshold tests, knee joint swelling, and passive range of motion assessed knee behavior. Cartilage tissue cytology, cytokine contents, and the mRNA and protein expression of PI3K/AKT/mTOR signaling pathway components were analyzed using HE and TUNEL staining, ELISA, RT-qPCR, and Western blotting, respectively. In addition, we used machine learning methods to conduct a secondary analysis of the dataset from the in vivo experiments in rats to verify the findings.

Results: Tuina significantly relieved pain and joint swelling, and improved range of motion. Staining showed reduced articular cartilage destruction and apoptosis. Tuina reduced the serum levels of IL-1β, IL-17, MMP-3, and MMP-13. Tuina downregulated Bax, ULK1, Beclin-1, LC3-II/I and upregulated PI3K, AKT, mTOR, and BCL-2 in cartilage tissue. The machine learning results indicated an 83.33% accuracy for the prediction model, remaining stable through both uni- and multivariate analyses. Tuina yielded the best comprehensive efficacy on KOA as well as better rat behavior and PI3K/AKT/mTOR signaling pathway improvement effect than positive drugs, while its cytokine-reducing ability was comparable to that of positive drugs.

Conclusion: Tuina can alleviate cartilage tissue injury in KOA, relieve inflammation, and reduce chondrocyte apoptosis and autophagy, the underlying mechanisms of which may be associated with activation of the PI3K/AKT/mTOR signaling pathway.