Abstract: The purpose of this study was to investigate the effect of Danshensu, the monomer component of Salvia miltiorrhiza, on the repair of skeletal muscle injury, in order to provide the theoretical basis for clinical treatment. The skeletal muscle injury models were established and treated with Danshensu. The process of skeletal muscle repair was observed via H.E. and Masson staining. Western blot and Q-PCR were used to detect the expression of muscle regeneration related factors (α-Actinin, eMyHC, MyoD, MyoG, Pax7 and MSTN), inflammation related factors (IL-6 and IL-10), macrophage type related factors (F4/80), scar tissue formation related factors (Collagen Ⅰ and α-SMA) and intermuscular adipose-related factors (PPAR-γ). The results showed that Danshensu reduced Evans Blue uptake of injure gastrocnemius muscle and significantly increased the expression levels of α-Actinin and eMyHC. Meanwhile, the expression levels of muscle regeneration related factors, MyoD, MyoG and Pax7, were also significantly increased and MSTN was obviously decreased after adding Danshensu. Danshansu significantly reduced the expression of F4/80 and accelerated the transformation of M1 macrophages into M2 macrophages, reducing the IL-6 mRNA level and increasing the IL-10 mRNA level. Masson staining showed that Danshensu reduced the distribution of collagen fibers. In addition, it also reduced the expression of Collagen I and α-SMA. Meanwhile, Danshensu significantly increased the expression of PPAR-γ in muscle. Therefore, Danshensu can promote muscle fiber regeneration and the formation of intermuscular adipose, reduce the formation of scar tissue, thereby accelerating the process of skeletal muscle repair and improving the quality of skeletal muscle repair.

Key words: skeletal muscle injury and regeneration, Danshensu, intermuscular adipose, inflammatory response, fibrosis