蛋白酶体抑制剂MG-132作用下失神经骨骼肌myf-5的表达

背景：MG-132是蛋白酶体抑制剂的一种，有报道显示其对失神经骨骼肌萎缩有延缓作用。 目的：进一步验证蛋白酶体抑制剂MG-132对大鼠骨骼肌成肌调节因子myf-5基因表达的影响。 方法：SD大鼠随机被分成3组，空白对照组不切断坐骨神经，仅做假手术，去神经组和去神经MG-132干预组切断坐骨神经1 cm以上，制作失神经骨骼肌动物模型，去神经MG-132干预组肌肉内注射MG-132。分别于去神经第2，7，28 d处死大鼠。用反转录聚合酶链式反应技术检测myf-5 mRNA表达情况，Western-blot检测myf-5蛋白表达的变化。 结果及结论：在去神经支配后第2，7，28天，与空白对照组比较，去神经组、去神经MG-132干预组myf-5mRNA和蛋白质均表达上调(P < 0.01)；去神经MG-132干预组myf-5mRNA和蛋白表达较去神经组均明显上调(P < 0.01)。结果提示蛋白酶体抑制剂MG-132可以通过抑制泛素-蛋白酶体途径来上调myf-5的表达，从而起到延缓骨骼肌萎缩的作用。

Effect of proteasome inhibitor MG-132 on myf-5 protein expression in rat denervated skeletal muscles

BACKGROUND: MG-132 is a kind of proteasome inhibitor, which has delaying effect on atrophy of denervated skeletal muscle. OBJECTIVE: To detect the effect of proteasome inhibitor MG-132 on expression of myogenic regulatory factors Myf-5 gene of denervated skeletal muscle in rats. METHODS: Sprague-Dawley rats were randomly divided into three groups. Sham operation were made only for the rats in the control group (sciatic nerves were not cut off). Sciatic nerves were cut off more than 1-cm at the mid-level on their right lower limbs for the rats in the denervated and MG-132 intervention groups. Rats were sacrificed at 2, 7, and 28 days after operation. The expression of Myf-5 mRNA was detected by RT-PCR, and the changes of myf-5 protein were determined by Western blot. RESULTS AND CONCLUSION: Compared with the control group, the expressions of Myf-5 mRNA and protein were increased in the denervated and MG-132 intervention groups at 2, 7, and 28 days after operation (P < 0.01). The increasing of Myf-5 mRNA in the MG-132 intervention group was greater than that in the denervated group (P < 0.01). The results suggested that the proteasome inhibitor MG-132 can inhibit the ubiquitin-proteasome pathway to increase the expression of Myf-5 gene in order to play the role of slowing skeletal muscle atrophy.