Massage relieves inflammation and oxidative stress and promotes autophagy after contusion of skeletal muscles

Objective To observe the effects of massage on inflammation, oxidative stress and autophagy during the repair of acute contusion of skeletal muscles so as to explore its biological mechanisms. Methods Forty-two adult Sprague-Dawley rats were randomly divided into a control group (n=6), a model group (n=18), and a treatment group (n=18). Acute contusion of the gastrocnemius muscles of the rats in the model and treatment groups was inflicted using a home-made impactor. Beginning forty-eight hours later, 15 minutes of massage was administered daily for two weeks. After one, 7 and 14 days of the massage treatment, the injured gastrocnemius was resected from 6 rats of both the model and treatment groups. Morphological changes were observed using haematoxylin and eosin (HE) staining. The serum content of tumor necrosis factor alpha (TNF-α), interleukin1β (IL-1β), C reactive protein (CRP) and prostaglandin E2 (PGE2) were detected using enzyme-linked immunosorbent assay (ELISA). The serum content of superoxide (SOD) and malondialdehyde (MDA) were detected using spectrophotometry. The expression of microtubule-associated protein 1 light chain 3(LC3), Bcl-2 homeodomain protein Beclin1 and ubiquitin binding protein P62 were detected using Western blotting. Results The HE staining showed more significant collapse and swelling of cells in the model group than in the control group at each time point. New muscle cells were observed at days 7 and 14 in the model group. At each time point, significantly better recovery was observed in the treatment group compared to the model group, with more new muscle cells and better cell morphology. According to the ELISA results, a significant increase in serum pro-inflammatory factors occurred in the model group compared to the control group and compared to the treatment group after one day and 7 days of treatment. The average serum content of SOD and MDA in the model group was significantly higher than in the control group, while the average serum content of SOD in the treatment group was significantly higher than in the model group and that of MDA was significantly lower. Western blotting showed a significant decrease in LC3 (II/I) and Beclin1, as well as a significant increase in P62 in the model group at each time point compared with the treatment group and the controls. Conclusion Inflammation and oxidative stress increase significantly in a skeletal muscle after injury, but autophagy decreases significantly. Massage can effectively reduce the inflammatory response and oxidative stress and promote autophagy, which leads to quicker repair of skeletal muscles. Key words: Massage; Skeletal muscles; Blunt injury; Inflammation; Oxidative stress; Autophagy