Extracorporeal Shock Wave and Melatonin Alleviate Joint Capsule Fibrosis after Knee Trauma in Rats by Regulating Autophagy

Background: Joint contracture is a common clinical problem affecting joint function. Capsule fibrosis plays a pivotal role in the progression of Joint contracture. Previous studies have reported that autophagy plays a regulatory role in visceral fibrosis.

Objective: This study aimed to investigate whether extracorporeal shock wave therapy (ESWT) and melatonin alleviate joint capsule fibrosis in rats with extended knee joint contracture by regulating autophagy.

Methods: A rat knee joint extension contracture model was made. Then, the rats were treated with ESWT, melatonin, ESWT + melatonin, or ESWT + melatonin + mTOR agonist for 4 weeks. The range of motion (ROM) of the knee joints was measured. Joint capsules were collected and observed for pathological changes by H&E and Masson staining. LC3B protein expression was evaluated by immunofluorescence staining. TGF-β1, MMP-1, Col-Ⅰ, Col-Ⅲ, LC3, ATG7, Beclin1, p-AMPK, p-mTOR and p-ULK1 protein expressions were measured by Western blot assay.

Results: The intervention groups had significantly improved ROM of knee joint (P < 0.05), significantly improved pathological changes on HE and Masson staining, significantly decreased protein expressions of TGF-β1, MMP-1, Col-Ⅰ, Col-Ⅲ and pmTOR (P < 0.05), and significantly increased protein expressions of LC3B, LC3II/LC3I ratio, ATG7, Beclin1, p-AMPK, and p-ULK1 (P < 0.05). Among these groups, the effects demonstrated by the ESWT + melatonin group were the best. With the mTOR agonist supplement, the therapeutic effects of extracorporeal shock waves and melatonin were significantly reduced.

Conclusion: ESWT plus melatonin alleviated knee joint capsule fibrosis in rats by regulating autophagy.