糖皮质激素在烧伤大鼠骨骼肌蛋白降解中的作用及其与蛋白酶体亚基表达的关系  

An experimental study on the role of glucocorticoid in protein breakdown of rats skeletal muscle and its relationship with proteasome subunit RC2 expression after burn injury

作　　者：吴焱秋[1] 柴家科[1] 盛志勇[1] 

机构地区：[1]解放军第304医院烧伤整形科,北京100037

出　　处：《中华实验外科杂志》2003年第3期211-213,T002,共4页Chinese Journal of Experimental Surgery

基　　金：国家自然科学基金资助项目 (39970 71 6;30 2 71 339) ;全军医药卫生科研基金资助项目 (98M1 55);全军科学技术研究"十五"规划基金重点课题 (0 1Z0 95)

摘　　要：目的　观察烧伤早期大鼠骨骼肌蛋白降解率和蛋白酶体亚基RC2的表达变化 ,探讨烧伤后骨骼肌大量消耗的分子机理。方法　采用大鼠背部 30 %TBSAⅢ度烧伤模型 ,应用骨骼肌离体孵育系统和氨基酸自动分析仪测定伸趾长肌蛋白降解率 ,同时应用Northernblot方法测定伸趾长肌蛋白酶体亚基RC2转录表达 ,采用放射免疫方法测定血浆糖皮质激素水平。结果　烧伤后大鼠伸趾长肌蛋白降解率显著增加 ,以肌纤维蛋白降解增加显著 (P <0 .0 1) ,蛋白酶体亚基RC2mRNA水平表达上调 ,且与肌纤维蛋白降解率间呈显著正相关 ( r=0 .92 3 7,P <0 .0 1)。血浆糖皮质激素水平烧伤后显著增加 (P <0 .0 1、0 .0 5 ) ,与RC2mRNA表达和肌纤维蛋白降解率间高度正相关 (r =0 .85 40、0 .80 10 ,P <0 .0 5 )。结论　烧伤后骨骼肌蛋白降解增强 ,以肌纤维蛋白降解最为显著 ,其与蛋白酶体亚基RC2转录表达增强关系密切 ,糖皮质激素在调节烧伤后骨骼肌蛋白降解中具有重要作用。Objective To observe the changes in proteolytic rate of skeletal muscle and expression of proteasome subunit RC2 in postburn rats,and investigate the molecular mechanism of skeletal muscle wasting.Methods The rats were subjected to 30% total body surface area (TBSA) Ⅲ°burn injury on the back.The proteolytic rate of extensor digitorium longus (EDL) muscle was determined by the in vitro muscle incubation system with sufficient oxygen supply as well as amino acid automatic analyzer,and the transcriptional expression of proteasome subunit RC2 was measured by Northern blot.The concentration of plasma glucocorticoid was determined by radioimmunological method.Results There was a marked increase in proteolytic rate of rats EDL muscle,especially in that of myofibrillar (P<0.01).Also,the mRNA abundance of proteasome subunit RC2 was up-regulated in EDL muscle after burn stimulation (P<0.01).The myofibrillar proteolytic rate was highly positively related to the expression of proteasome subunit RC2 (r=0.9237,P<0.01).Highly positive relation was observed between plasma glucocorticoid and myofibrillar proteolytic rate and transcriptional expression of proteasome subunit RC2 (r= 0.854?0,0.801?0,P<0.05).Conclusion Increased proteolytic rate of skeletal muscle,especially myofibrillar proteolytic rate is closely related to activation of proteasome subunit RC2 in transcriptional level after burn injury in rats,and glucocorticoid may play an important role in skeletal muscle protein breakdown after burn.

关 键 词：糖皮质激素 烧伤 大鼠 骨骼肌蛋白降解 基因表达 分子生物学 

分 类 号：R644[医药卫生—外科学]