氨哮素延缓臂丛神经损伤后骨骼肌萎缩的机理研究

Molecular echanism of the effect of clenbuterol on delaying skeletal muscle atrophy following brachial plexus injury

目的 探讨氨哮素对臂丛神经损伤后骨骼肌萎缩的延缓作用及其机制。方法 建立大鼠一侧臂丛神经损伤模型 ,按术后服药的不同分成两组。 (1)氨哮素组 :术后灌服氨哮素 (10mg/kg·d-1) ,6只大鼠。 (2 )对照组 :术后灌服等量蒸馏水 ,7只大鼠。术后 6周取两组手术侧的肱二头肌 ,观察萎缩肌肉的肌湿重、总蛋白含量的变化 ;用TUNEL法检测凋亡肌细胞的百分率 ,并用免疫组化法检测肌萎缩时Fas、Caspase 8、P 2 1的表达。结果 (1)氨哮素组 :失神经侧的臂围明显大于对照组失神经侧 ,两组差异有显著性意义 (t =5 .49,P <0 .0 1)。肌湿重和总蛋白含量也明显高于对照组 (t =7.5 4,P <0 .0 1;t =3 .81,P <0 .0 5 )。 (2 )肌细胞凋亡率 :氨哮素组 :萎缩肌肉内肌细胞的凋亡程度明显轻于对照组 ,两组差异有显著性意义 (t =8.0 0 ,P <0 .0 1)。 (3)氨哮素组的Fas、Caspase 8表达明显降低 ,两组差异有显著性意义 (t =7.6 7,P <0 .0 1;t =5 .37,P <0 .0 1) ,P 2 1表达明显增高 ,两组差异有显著性意义(t =6 .86 ,P <0 .0 1)。结论 氨哮素对防治臂丛神经损伤后的骨骼肌萎缩有一定的疗效 。

Objective To investigate the effect of clenbuterol on delaying skeletal muscle atrophy after brachial plexus injury and its mechanism. Methods The model of brachial plexus injury of one side was set up in rats. They were divided into two groups according to the postoperative medication .Six rats in clenbuterol group and 7 in control group were administered clenbuterol (10 mg/kg·d -1 ) and distilled water p.o. respectively. The wet weight and total protein amount of biceps were measured at 6 weeks postoperatively. The percentage of muscle cells by apoptosis was detected by TUNEL method and the expression of Fas, Caspase 8 and P 21 were checked by immunohistochemical method (ABC). Results Compared with control group, there was significantly greater increase in circumference of affected upper limb( t =5.49, P <0.01), wet muscle weight, total protein amount ( t =7.54, P <0.01; t =3.81, P <0.05), and expression of P 21 ( t =6.86, P <0.01), as well as a greater reduction in apoptotic muscle cells ( t =8.00, P <0.01), and expression of Fas, Caspase 8 ( t =7.67, P <0.01; t =5.37, P <0.01). There were statistically significant difference between the groups. Conclusions Clenbuterol plays a certain role in preventing skeletal muscle atrophy. Its mechanism lies in the anti apoptosis effect.