Effects of electroacupuncture on gait and proliferation and differentiation of muscle satellite cell in rats with acute blunt trauma of gastrocnemius muscle / 中国针灸

OBJECTIVE@#To observe the effects of electroacupuncture on threshold of pain, gait, proliferation and differentiation of muscle satellite cell in rats with acute blunt trauma of gastrocnemius muscle, and to explore the possible mechanism of electroacupuncture in promoting the repair of acute injury of skeletal muscle.@*METHODS@#A total of 48 SD rats were randomly divided into a blank group (6 rats), a model group (24 rats) and an electroacupuncture group (18 rats). In the model group and the electroacupuncture group, the model of acute blunt trauma of gastrocnemius muscle was established by self-made impactor. In the electroacupuncture group, electroacupuncture was applied at "Chengshan" (BL 57) and "Yanglingquan" (GB 34) on the right side, with disperse-dense wave, in frequency of 2 Hz/100 Hz, once a day, 30 min each time. Electroacupuncture intervention was performed for 3, 7 and 14 days according to the sampling time. On the 1st, 3rd, 7th and 14th days after modeling, the mechanical withdrawal pain threshold of hindfoot was detected by Von Frey method; the standing time and the maximum contact area of the right hindfoot were recorded by Cat Walk XTTM animal gait analysis instrument; the morphology of the right gastrocnemius muscle and the number of inflammatory cells were observed by HE staining; the positive expression of paired box gene 7 (Pax7) and myogenic differentiation (MyoD) of the right gastrocnemius muscle was detected by immunofluorescence.@*RESULTS@#After modeling, the muscle fiber rupture and massive infiltration of red blood cells and inflammatory cells were observed in the right gastrocnemius muscle; after electroacupuncture intervention, the morphology of muscle fiber was intact and the infiltration of inflammatory cells was improved. Compared with the blank group, in the model group, the differences of mechanical withdrawal pain threshold between the left and right foot were increased (P<0.05), the standing time was shortened and the maximum contact area of the right hindfoot was decreased (P<0.05), the number of inflammatory cells and the positive expression of Pax7 and MyoD of the right gastrocnemius muscle were increased (P<0.05) on the 1st, 3rd, 7th and 14th days after modeling. Compared with the model group, in the electroacupuncture group, the differences of mechanical withdrawal pain threshold were decreased (P<0.05), the standing time was prolonged (P<0.05), the number of inflammatory cells of right gastrocnemius muscle was decreased (P<0.05) on the 7th and 14th days after modeling; the maximum contact area of the right hindfoot was increased (P<0.05), the positive expression of MyoD of the right gastrocnemius muscle was increased (P<0.05) on the 3rd, 7th and 14th days after modeling; the positive expression of Pax7 of the right gastrocnemius muscle was increased (P<0.05) on the 3rd day after modeling.@*CONCLUSION@#Electroacupuncture can effectively improve the pain threshold and gait in rats with acute blunt trauma of gastrocnemius muscle, and promote the repair of skeletal muscle injury, the mechanism may be related to the up-regulation of Pax7 and MyoD, so as to promoting the proliferation and differentiation of muscle satellite cell.

Changes in expression of autophagy-related factors during acute contusion repair of skeletal muscle / 中国应用生理学杂志

<p><b>OBJECTIVES</b>To explore the possible biological mechanism of skeletal muscle contusion repair through researching the changes in expression of autophagy-related genes and proteins in SD rats with acute skeletal muscle contusion.</p><p><b>METHODS</b>Six rats were randomly selected as the control group from 30 male SD rats, acute skeletal muscle contusion model were established in the remaining 24 rats with self-made hitter, then the model rats were randomly divided into 4 groups (3 d, 5 d, 7 d, 14 d groups, =6). On the 3, 5, 7 and 14 day after injury, injured gastrocnemius of each group was harvested. The morphological and the ultra-microstructure changes of gastrocnemius after injury were observed by HE staining and transmission electron microscope (TEM) respectively. The relative protein levels of (LC3-Ⅱ) and P62 of each group were observed by Western blot. The relative mRNA levels of atg7, atg10, atg12, atg16L1 of each group were observed by RTPCR.</p><p><b>RESULTS</b>The results of HE staining showed that compared with the control group, the inflammation reached its peak on the 5 day after injury, new muscle fibers were clearly observed in 7 d group. The results of TEM showed that, compared with the control group, oncotic mitochondria could be clearly seen in the 3 d, 5 d, 7 d groups. Also, the Z line changed from disappearing to drift thickening, sarcoplasmic reticulum dilatation gradually improved, there was no evident difference between the 14 d group and the control group, suggesting that the damage has preliminarily healed. The results of Western blot showed that the expressions of LC3-Ⅱand P62 were increased at first and then decreased. The expression of LC3-Ⅱwas markedly up-regulated in the 3 d, 5 d, 7 d groups compared with the control group and the 14 d group (<0.01). Similarly, compared with the control group, the expression of P62 reached its peak on the 3 day after injury (<0. 01), and returned to normal level on the 14 day. The results of RT-PCR showed that the expression of atg10 mRNA in the natural recovery group of 3 d, 5 d, 7 d, 14 d was firstly decreased and then increased, the atg10 mRNA was markedly down-regulated in the 3 d, 5 d, 7 d groups compared with the control group and the 14 d group (<0. 01). The expression of atg7, atg12, atg16L1 mRNA was generally increased at first and then decreased, it was markedly up-regulated in the 3 d, 5 d, 7 d groups compared with the control group and the 14 d group (<0.01, <0.05, <0.01).</p><p><b>CONCLUSIONS</b>The above results indicate that the autophagy is involved in repair of skeletal muscle injury by its autophagyrelated factors,regularly changes after contusion, and the rate of damage repair may be related to the level of autophagy.</p>