Objective: To observe the efficacy of electroacupuncture (EA) plus passive stretch exercise in the treatment of disused atrophy of gastrocnemius and soleus muscles in mice.
Methods: Fifty C57BL/6 mice were randomly and equally divided into 5 groups: blank control, model, passive stretch exercise (exercise), EA and EA+exercise groups. The muscular atrophy model was established by fixing the gastrocnemius and soleus muscles with plaster immobilization (by putting the right leg into a plastic vial and then twining the vial with medical plaster bandage from the ankle upwards to the thigh and groin to maintain the knee-joint flexion and ankle joint plantar flexion for 7 days). EA (2 Hz/100 Hz, 1 mA)was applied to bilateral "Zusanli"(ST36) for 10 min, once a day for 4 weeks. For mice with the passive exercise, the plastic vial was removed first, followed by pulling out the hindleg to seize the toes to stretch them until the right hindleg is fully extended, then, pushed the leg towards the body. The procedures were repeated once again and again for 10 min. The exercise was conducted once daily, for 4 weeks. The cross-sectional area of fast and slow muscle fibers of the soleus and gastrocnemius was measured under electronic microscope after ATPase histochemical stain and the expression of slow skeletal muscle troponin (TNNI1) and fast skeletal muscle troponin (TNNI2) in the soleus and gastrocnemius was detected by Western blot.
Results: Compared with the blank control group, the cross-sectional areas of the fast and slow muscle fibers of the soleus and gastrocnemius muscles were significantly decreased in the model group (P<0.05, P<0.01). Following the interventions, the cross-sectional areas of the fast and slow muscle fibers of soleus muscle in the EA+exercise group, and those of the fast and slow muscle fibers of the gastrocnemius muscle in the EA and EA+exercise groups, and the expression levels of TNNI1 and TNNI2 proteins in the gastrocnemius muscle of the EA+exercise group were significantly increased in comparison with the model group (P<0.05, P<0.01).
Conclusion: EA combined with passive stretch exercise can promote the recovery of the soleus and gastrocnemius muscles in disused muscle atrophy mice, which may be related to its effect in up-regulating the expression of TNNI1 and TNNI2 proteins.
目的：观察电针和被动牵伸运动对小鼠后肢石膏固定制动所致腓肠肌、比目鱼肌废用性肌萎缩的影响，探讨电针结合被动牵伸运动对废用性肌萎缩小鼠骨骼肌恢复的作用。方法：将50只C57BL/6小鼠随机分为空白对照组、模型对照组、电针干预组、被动运动组和结合干预组，每组10只。除空白对照组外，其余4组均采用石膏固定方法制备废用性骨骼肌萎缩模型。电针干预组给予双侧“足三里”电针治疗，每次10 min，1次/d；被动运动组双下肢进行被动牵伸运动，每次10 min，1次/d；结合干预组每次电针干预5 min，被动牵伸5 min，1次/d。各组均干预4周。用肌肉形态ATPase法观察各组小鼠肌纤维横截面积的变化，Western blot法检测慢速骨骼肌型肌钙蛋白(TNNI1)、快速骨骼肌型肌钙蛋白(TNNI2)的表达。结果：与空白对照组比较，模型对照组小鼠比目鱼肌与腓肠肌的快、慢肌纤维横截面积显著下降(P<0.05，P<0.01)。与模型对照组比较，电针干预组小鼠腓肠肌快、慢肌纤维横截面积显著升高(P<0.05)；结合干预组小鼠比目鱼肌、腓肠肌的快、慢肌纤维横截面积及腓肠肌TNNI1、TNNI2蛋白相对表达量显著升高(P<0.05，P<0.01)。结论：电针结合被动牵伸运动的治疗较单纯被动牵伸运动，能显著促进肌肉横截面积的恢复，同时还可以促进腓肠肌肌钙蛋白的表达，提示临床采用电针结合被动牵伸运动可促进固定制动导致的肌萎缩康复。.
Keywords: Disused muscle atrophy; Electroacupuncture; Fast skeletal muscle troponin (TNNI2); Gastrocnemius; Passive stretch exercise; Slow skeletal muscle troponin (TNNI1); Soleus.