高频正弦波振动对制动大鼠比目鱼肌萎缩的对抗作用

Antagonistic effect of high frequency sinusoidal vibration on immobilization-induced soleus muscle atrophy in rats

背景:肌梭的传入冲动减少与失用性肌萎缩的发生密切相关。高频正弦波振动能够兴奋肌梭,肌梭传入活动的增加可以增强骨骼肌的肌电活动,理论上能对抗比目鱼肌萎缩。目的:验证高频正弦波振动对后肢制动大鼠比目鱼肌萎缩的对抗作用。设计、时间及地点:随机对照动物实验,于2008-05/2009-01在西安交通大学医学院教育部重点实验室完成。材料:SPF级健康成年雌性SD大鼠30只,按随机配对原则分为3组:正常对照组、制动组、振动组,每组10只动物。方法:除正常对照组外,采用大鼠后肢制动(石膏固定)作为肌肉失用模型,在后肢制动的14d期间,振动组大鼠制动肢体的比目鱼肌部位实施高频振动(100Hz;500μm,480s/d)。之后取各组大鼠比目鱼肌。主要观察指标:①称其湿质量,计算出湿质量体质量比。②采用酶组化染色及计算机图像分析技术测定骨骼肌纤维的横截面积以及Ⅰ、Ⅱ型肌纤维的构成比。结果:①14d后,制动组大鼠比目鱼肌湿质量、湿质量/体质量及肌纤维横截面积与对照组相比明显减小(P<0.05);同时,制动组大鼠比目鱼肌Ⅰ型肌纤维所占比例下降而Ⅱ型肌纤维比例增高(P<0.05)。②制动加高频振动组大鼠14d后,与制动组相比,比目鱼肌的湿质量、湿质量/体质量及肌纤维横截面积均有明显增大(P<0.05)。结论:高频正弦波振动可有效地对抗(预防)制动引起的比目鱼肌萎缩。

BACKGROUND： The decrease in muscle spindles afference is closely related to the occurrence of disused muscle atrophy. High frequency sinusoidal vibration （HFV） has the effect of exciting muscle spindles, and increasing muscle spindles afference can result in an increase in myoelectrical activity of skeletal muscles, from which we conclude that HFV can antagonize soleus muscle atrophy in rats. OBJECTIVE： To investigate the antagonistic effect of HFV on soleus muscle atrophy induced by hindlimb immobilization of rats. DESIGN, TIME AND SETTING： Randomized controlled animal experiment was performed in Key Laboratory of Ministry of Education, Medical College of Xi＇an Jiaotong University from May 2008 to January 2009. MATERIALS： Thirty healthy adult female SPF grade rats were randomly divided into three groups, termed normal control group, immobilization group and vibration group, with 10 rats in each group. METHODS： All rats except those in the normal control group were made into models of disused muscles through the immobilization in their hindlimbs. Then, during the 14-day hindlimb immobilization period, HFV（100 Hz; 500 μm） were applied to the immobilized soleus muscles in the vibration group. Afterwards, sections of soleus muscles of each group were obtained to exercise study on them. MAIN OUTCOME MEASURES： ①The muscle wet weight （MWW） and the ratio of muscle wet weight to body weight （MWW/BW） of the soleus muscles. ②The cross-sectional area （CSA） and the constituent ratio （type Ⅰ and Ⅱ ） of skeletal muscle fibers were determined with enzyme-histochemical staining and computer image analysis technology. RESULTS： ①Compared with the control group, the vibration group had got significant decreases in the MWW, the MWW/BW as well as the CSA skeletal muscle fibers （P 〈 0.05）; At the same time, the soleus muscles fibers showed an evident shift toward a decreased percentage of fibers type Ⅱ, but an increased percentage of typeⅡ （P 〈 0.05）. ②The 14-day application of HFV resulted in significant increases in the MWW, the MWW/BW and the CSA of skeletal muscle fibers in the vibration group, compared with the immobilization group （P 〈 0.05）. CONCLUSION： HFV is effective in antagonizing （and preventing） the atrophy of soleus muscles induced by immobilization.