Duhuo Jisheng Decoction Regulates Intracellular Zinc Homeostasis by Enhancing Autophagy via PTEN/Akt/mTOR to Improve Knee Cartilage Degeneration
BackgroundArticular cartilage degeneration as well as cartilage matrix degradation is one of the key pathological changes in the early stage of knee osteoarthritis (KOA). However, currently, there are limited early prevention and treatment options available. Duhuo Jisheng Decoction (DHJSD) is a formula from Bei Ji Qian jin Yao Fang compiled by Sun Simiao in the Tang Dynasty of China. As a complementary therapy, it is widely used to treat early-stage KOA in China, but its mechanism has not been fully elucidated. ObjectiveThis study is aiming at investigating the potential role and mechanism of DHJSD in protecting cartilage from degradation. MethodsThe mechanism of DHJSD in alleviating OA was explored by gene silencing technology combined with a series of functional experiments in primary rat chondrocytes. Next, 25 wistar rats were used to validate the results obtained in vitro. The PTEN, Akt, mTOR, MMP13, Zn, collagen II, autophagy and apoptosis were determined. ResultsDHJSD reduced the phosphorylation of Akt and mTOR and the expression of zinc, MMP13, Bax and Bcl2. DHJSD increased the level of autophagy and the expression of autophagy proteins LC3 and Beclin1. After silencing PTEN gene, the phosphorylation levels of Akt and mTOR and the effects of Bax, Bcl2, LC3 and Beclin1 were weakened by DHJSD. DHJSD increased the formation of autophagosomes in chondrocytes. Histopathological staining revealed that DHJSD had a protective effect on cartilage. ConclusionDHJSD inhibits Akt/mTOR signaling pathway by targeting PTEN to promote autophagy in chondrocytes, which may be closely to repress the formation of MMP-13 by regulating the level of zinc in chondrocytes.