脓毒症大鼠骨骼肌蛋白降解增强与泛素转录表达关系的研究  

Study on the relationship between protein breakdown and transcriptionalexpression of ubi-quitin in skeletal muscle in rats with sepsis

作　　者：柴家科[1] 吴焱秋[1] 盛志勇[1] 

机构地区：[1]解放军304医院烧伤研究所,北京100037

出　　处：《军医进修学院学报》2002年第2期81-85,共5页Academic Journal of Pla Postgraduate Medical School

基　　金：国家自然科学基金资助项目 ( 39970 716 ) ;"九五"军队科研基金项目 ( 98M15 5 ) ;"十五"军队科研基金项目 ( 0 1Z0 95)

摘　　要：目的 :测定脓毒症大鼠骨骼肌蛋白降解率的变化 ,探讨骨骼肌蛋白降解的分子机制。方法 :腹腔注射内毒素建立大鼠脓毒症模型 ,动物随机分成 4组 ,分别为腹腔注射内毒素后 2h、6h、12和 2 4h组 ,每组各设正常对照。借助骨骼肌充分氧供离体孵育系统 ,氨基酸自动分析仪测定不同时相点孵育液中伸指长肌总蛋白降解率和肌纤维蛋白降解率 ;应用northernblot方法测定伸指长肌组织泛素mRNA的表达变化 ,分析骨骼肌蛋白降解与泛素mRNA表达的关系。结果 :脓毒症大鼠伸趾长肌总蛋白降解率在 2h和 6h轻度增加 ,肌纤维蛋白降解率则在 2h和 6h增加 1 5～ 2 2倍 ,在 12h增加 40 %。伸指长肌组织泛素mRNA 2 4kb的水平主要在 2h和 6h增加明显 ,增幅达 2～ 5倍 ,泛素mRNA 1 2kb未见明显变化 ;肌纤维蛋白降解与泛素mRNA 2 4kb表达间呈显著正相关 (r =0 9731,P =0 0 0 3)。结论 :脓毒症时骨骼肌蛋白降解增加可能同泛素 蛋白酶体蛋白降解途径活性增强相关。Objective:To determinethe changes in proteolytic rate and mRNA expression of ubiquitin in rat skeletal muscle, and investigate the molecular mechanism of skeletal muscle protein catabolism during sepsis. Methods: The ratswith sepsis was established by administering endotoxin into theperitonealcavity. The rats were randomly divided into 4 groups as follows: 2h, 6h, 12hand 24h after administration of endotoxin, 16 animals for each group including 8 normal controls. We use the in vitro muscle incubation system with sufficient oxygen supply as well as amino acid automatic analyzer for detection of the proteolytic rate of extensor digitorium longus(EDL) muscle in the samples. The mRNA expression of ubiquitin in rat EDL muscle was determined by northern blot analysis. Results: Total proteolytic rate in EDL muscle increased slightly at 2h and 6h after administering endotoxin into theperitonealcavity, no statistically significant difference was observed at 12h and 24h,there was a progressive 1～2-fold increase in myofibrillar proteolytic rate at 2h and 6h, 40% increase at 12h, respectively, as compared with that of normal control(P<0.01). Ubiquitin mRNA-2.4kb rose by 2～5-fold at 2h and 6h after administering endotoxin into theperitonealcavity(P<0.01), but not at 12h and 24hcompared with that of normal control. There was no statistically significant changein ubiquitin mRNA-1.2kb.Significantly positive correlation between myofibrillar proteolysis and expression of ubiquitin mRNA-2.4kb was observed(r=0.9731, P=0.003). Conclusion: The enhancement in skeletal muscle proteolysis is probably relative to activation of ubiquitin-proteasome pathway.

关 键 词：脓毒症 骨骼肌 大鼠 RNA印迹法 

分 类 号：R631.1[医药卫生—外科学]