Abstract: OBJECTIVE: To investigate the effects of Gyejibokryeong-Hwan(Guizhifuling-wan, GBH) on muscle injury in a mouse model of muscle contusion.METHODS: C57/BL6 mouse biceps femoris muscles were injured using the drop-mass method and injured animals were treated orally with GBH(50,100, or 500 mg/kg) once a day for 7 d. Open field and treadmill running tests were performed to assess functional recovery from muscle injury. The production of pro-inflammatory cytokines was examined by enzyme-linked immunosorbent assay and Western blotting analysis. Expression of the muscle regeneration biomarkers, myoblast determination(Myo D), myogenic factor 5(Myf5), and smooth muscle actin(α-SMA), in the biceps femoris muscle was investigated at the protein and m RNA level by Western blotting and real time-PCR, respectively. Histological analysis was performed using hematoxylin and eosin staining. Finally, myosin heavy chain production was investigated in differentiated C2C12 myoblasts in the presence of GBH.RESULTS: GBH treatment markedly improved locomotion and running behavior. GBH significantly inhibited the secretion of monocyte chemoattractant protein-1 into the bloodstream in muscle-contused animals. The levels of Myo D, Myf5, and α-SMA protein and m RNA were significantly up-regulated by GBH in injured muscle tissue. Histological studies suggested that GBH facilitated recovery from muscle damage. However, GBH did not induce the production of myosin heavy chain in vitro.CONCLUSION: Overall, the present study suggested that GBH improves the recovery of the injured muscles in the mouse model of muscle contusion.

Key words: muscles, wounds and injuries, contusions, regeneration, muscle,skeletal, myogenic regulatory factor 5, Gyejibokryeong-Hwan