泛素特异性蛋白酶19对烟熏诱导慢性阻塞性肺疾病大鼠模型骨骼肌萎缩的作用及机制

目的 通过烟熏制备慢性阻塞性肺疾病(COPD)大鼠模型,研究泛素特异性蛋白酶-19(USP-19)在COPD相关骨骼肌萎缩中的作用及机制.方法 烟熏诱导大鼠COPD模型,观察肺及骨骼肌组织的组织形态学变化,利用蛋白质印迹法(Western blotting)及实时定量聚合酶链式反应(RT-PCR)观察骨骼肌细胞内USP-19、肌球蛋白重链(MHC)及丝裂原活化蛋白激酶(MAPKs)基因的表达情况.结果 烟熏建立的大鼠COPD模型,大鼠肺组织呈肺气肿改变,烟熏12周时,每高倍镜视野下肌纤维数量增多40％,间接提示骨骼肌发生萎缩;骨骼肌细胞肉MHC表达明显下调,与烟熏时间呈负相关;萎缩的骨骼肌细胞内USP-19基因的转录和表达均明显上调,与烟熏时间呈正相关,与MHC表达呈负相关;萎缩的骨骼肌细胞内MAPKs通路磷酸化水平明显增强(P＜0.05).结论 USP-19基因参与COPD模型鼠骨骼肌萎缩的发生,起负性调节作用,此作用可能通过MAPKs通路实现.

Effect and Mechanism of Ubiquitin-specific Peptidase 19 on Muscle Atrophy of Chronic Obstructive Pulmonary Disease Induced by Cigarette Smoke Exposure in Rats

Objective To investigate the effects of ubiquitin-specific peptidase 19 (USP-19) on rats bearing chronic obstructive pulmonary disease (COPD) induced by cigarette smoke (CS) exposure.Methods Rats exposed to chronic CS was chosen for the study.For histological examination,lungs and quadriceps femoris muscle were stained with hematozylin and eosin.Total RNA and protein were extracted for Real-time PCR and Western blot analysis to assess the MHC,USP-19 and MAPKs gene expression.Results Twelve weeks CS exposure produced lung lesions that morphologically resembled human emphysema,leading to the enlargement of alveolar ducts.Skeletal cell numbers per high-power (HP) lens increased after 12 weeks by 40％ in comparison with the control group,suggesting muscle wasting.Chronic CS exposure decreased the mRNA level of MHC.MHC protein content in the quadriceps femoris muscle was decreased in the 8-and 12-week groups.CS significantly stimulated phosphorylation of ERK1/2,p38 without altering the total ERK1/2,p38 content.Conclusions Cigarette smoke-induced skeletal muscle atrophy is associated with up-regulation of USP-19,which via MAPKs probably.