电针对骨骼肌钝挫伤大鼠神经肌肉接头重建相关蛋白MuSK和APP表达的影响

Effect of Electro-Acupuncture on Expressions of Neuromuscular Junction Remo-deling Related Proteins of MuSK and APP in Rats with Skeletal Muscle Contusion

目的:通过观察电针对急性骨骼肌钝挫伤大鼠恢复过程中肌特异性受体酪氨酸激酶(MuSK)和淀粉样前体蛋白(APP)表达的影响,初步探讨电针促进骨骼肌神经肌肉接头重建的相关机制。方法:将54只雄性SD大鼠随机分为正常对照组(A组)、模型组(B组)、电针组(C组),每组18只。采用自制重物打击装置建立大鼠右侧骨骼肌急性钝挫伤模型,A组不造模。B组造模后自然恢复,C组选取左侧“足三里”和右侧“阿是穴”在造模后24 h行电针治疗,15 min/次,2 d 1次。于造模后7、28、56 d分别取材6只动物,采用HE染色观察大鼠腓肠肌组织形态结构的变化,Western Blot检测MuSK及APP的蛋白表达情况。结果:HE结果显示正常大鼠腓肠肌肌纤维排列整齐,呈粉色,肌细胞大小均匀整齐。造模后7 d,B组大鼠腓肠肌肌纤维溶解断裂、排列紊乱且有大量炎性细胞浸润;C组出现少量新生肌细胞和肌纤维形成且排列略为整齐;造模后28 d,B组大鼠新生肌细胞增多,炎性细胞减少,有部分肌纤维形成但排列仍不整齐;C组大鼠肌纤维进一步增多且排列较为整齐;造模后56 d,B组大鼠肌纤维排列逐渐整齐,炎性细胞明显减少;C组大鼠腓肠肌损伤基本愈合,形态结构基本完整。Western blot结果显示,在正常大鼠骨骼肌中MuSK、APP蛋白的表达水平均较少;造模成功后,与A组相比各取材时间点B组大鼠骨骼肌内MuSK、APP蛋白的表达增多且差异具有统计学意义(P<0.05);与B组相比,C组MuSK和APP蛋白在损伤后第7天时表达升高,第28天时达到峰值,56 d时表达有所回落,且各取材时间点C组表达高于B组(P<0.05)。结论:电针可以促进急性骨骼肌钝挫伤大鼠骨骼肌的恢复,正向调控骨骼肌修复过程中MuSK、APP的表达,从而有利于NMJ的再生。

Objective:To explore the mechanism of electro-acupuncture promoting the reconstruction of neuromuscular junction(NMJ)of skeletal muscle by observing its effect on the expressions of MuSK and APP in the process of acute skeletal muscle contusion in rats.Methods:54 male SD rats were randomly divided into the normal group,the model group and the electro-acupuncture group,with 18 rats in each group.The model of acute skeletal muscle blunt contusion was established by using self-made striking device.The electro-acupuncture group was treated with electro-needling Zusanli(ST36)and Ashi points.On the 7th,28th and 56th day after modeling,6 rats were taken from each group at each time point,the morphological changes of rat gastrocnemius muscle were observed by HE staining method,and the protein expressions of MuSK and APP were detected by Western Blot method.Results:HE staining showed that the muscle fibers of gastrocnemius muscle of normal rats were arranged neatly and appeared pink,and the size of muscle cells was uniform and neat.On the 7th day after modeling,the gastrocnemius muscle fibers in the model group were broken,disarranged and infiltrated with a large number of inflammatory cells;in the electro-acupuncture group,a small number of newborn muscle cells and muscle fibers were formed and arranged slightly neatly.On the 28th day after modeling,the number of new muscle cells increased and inflammatory cells decreased in the model group,and some muscle fibers were formed but arranged irregularly;the muscle fibers in the electro-acupuncture group increased obviously and arranged neatly.On the 56th day after injury,the muscle fibers in the model group were arranged neatly and inflammatory cells decreased greatly;in the electro-acupuncture group,the injury of gastrocnemius muscle was basically healed and the structure was basically intact.The results of Western Blot showed that the expression levels of MuSK and APP proteins in skeletal muscle of normal rats were lower.After modeling,the protein expressions of MuSK and APP in skeletal muscle were significantly higher in the model group than those in the normal group(P<0.05).The protein expressions of MuSK and APP increased on the 7th day after injury in the electro-acupuncture group,reached the peak on the 28th day,and decreased on the 56th day;the expressions in the electro-acupuncture group were higher than those in the model group at each same time point(P<0.05).Conclusion:Electro-acupuncture can promote the recovery of skeletal muscle in rats with acute skeletal muscle contusion,and positively regulate the protein expressions of MuSK and APP in the process of skeletal muscle repair,so as to promote the regeneration of NMJ.