Artesunate protects against surgery-induced knee arthrofibrosis by activating Beclin-1-mediated autophagy via inhibition of mTOR signaling.

Intraarticular fibrosis following knee surgery is a troublesome complication and remains a challenging problem for clinicians. Artesunate (ART), a classical anti-malarial drug extracted from the Chinese medicinal herb Artemisia annua L, has been associated with some fibrosis-related diseases. However, its effect and underlying mechanism on knee arthrofibrosis are still obscure. In the present study, we found that ART induced cellular autophagy flux and inhibited cell proliferation in fibroblasts. Intriguingly, genetic depletion of Beclin-1 abolished ART-triggered cellular autophagy and further attenuated the inhibitory effect of ART on fibroblasts proliferation. Moreover, at molecular level, our results demonstrated that ART-induced autophagy activation was associated with the inhibition of mTOR signaling through PI3K/AKT/mTOR pathway and AMPK/mTOR pathway. In vivo, ART treatment triggered autophagy activation and alleviated the severity of surgery-induced knee arthrofibrosis. Taken together, we concluded that ART exhibited anti-proliferation efficacy in fibroblasts and alleviated the severity of knee arthrofibrosis in rabbits by inducing Beclin-1-mediated autophagy via inhibition of mTOR signaling. These findings indicated that ART might be a potential therapeutic agent for preventing the progression of surgery-induced intraarticular fibrosis of knee.