骨骼肌胰岛素受体底物-1及其丝氨酸磷酸化与酪氨酸磷酸化在感染大鼠胰岛素抵抗中的作用  

Effects of insulin receptor substrate-1 and its serine phosphorylation and tyrosine phosphorylation on insulin resistance in skeletal muscle cells in the state of sepsis: experiment with rats

作　　者：燕晓雯[1] 李维勤[1] 王晓东[1] 黎介寿[1] 李宁[1] 

机构地区：[1]南京大学医学院临床学院(南京军区南京总医院)全军普通外科研究所外科重症监护科,210002

出　　处：《中华医学杂志》2006年第41期2922-2927,共6页National Medical Journal of China

基　　金：军队"十五"科研基金重点资助项目(编号01Z011)

摘　　要：目的研究不同程度感染大鼠骨骼肌胰岛素受体底物-1(IRS-1)及其丝氨酸(Ser307)磷酸化和酪氨酸(Tyr)磷酸化在胰岛素抵抗(IR)中的作用。方法SD大鼠随机分为对照组、10%组和30%组。10%组和30%组大鼠用盲肠结扎穿孔制造感染模型,结扎长度分别为总长度的10%和30%,对照组为假手术组。3组大鼠分别在术前和术后各时间点取空腹血和后腿腓肠肌后处死。测定血浆空腹血糖(FPG)、空腹血胰岛素(FINS)、TNF-α和IL-6浓度,计算IR指数(lgIRI),同时检测IRS-1及其Tyr磷酸化和Ser307磷酸化水平。结果3组大鼠生存曲线之间,均差异有统计学意义(P<0·01)。术后10%组和30%组TNF-α和IL-6均明显高于对照组(均P<0·01),其中30%组更高(均P<0·01)。术后10%组和30%组FPG、FINS和lgIRI在各时间点均明显高于对照组(均P<0·01),而30%组则明显高于10%组(P<0·01),术后FINS升高程度要明显高于FPG。对照组和30%组IRS-1均呈阳性位于骨骼肌细胞质内;对照组IRS-1Tyr磷酸化呈阳性,而30%组仅呈散在阳性;对照组IRS-1Ser307磷酸化呈阴性,而30%组呈强阳性。半定量分析显示30%组IRS-1在术后各个时间点与对照组相似(均P>0·05),IRS-1Tyr磷酸化在30%组术后各时间点明显低于对照组(均P<0·01),IRS-1Ser307磷酸化在术后各时间点明显高于对照组(均P<0·01)。lgIRI与IRS-1Tyr磷酸化呈显著负相关(r=-0·957,P<0·01),与IRS-1Ser307磷酸化呈显著正相关(r=0·955,P<0·01)。结论感染状态下骨骼肌细胞内IRS-1的含量不变,而是其Tyr磷酸化降低,同时Ser307磷酸化增强,其变化程度与机体胰岛素抵抗程度密切相关。Objective To investigate the effects of insulin receptor substrate （IRS） -1 and its serine （Ser）^307 phosphorylation and tyrosine （Tyr） phosphorylation on insulin resistance in skeletal muscle cells in the state of sepsis. Methods 120 SD rats were randomly divided into 3 groups： 10% group, with 10% of the total cecal length ligated and punctured without use of antibiotic so as to make sepsis model; 30% group, with 30% of the total cecal length ligated and punctured ; and control group, undergoing sham operation. Fasting venous blood samples were collected before the operation to detect the fasting plasma glucose （FPG）. 0, 8, 16, 24, and 48 hours after the operation 8 rats in each group underwent fasting of food and without fasting of water for 8 hours, i. e. , until the 8 th, 16 th, 24 th, 48 th, and 72 nd hours after the operation. Then the rats underwent anesthesia, with blood sample from the vena cava and specimen of gastrocnemius of the hind leg collected, and then killed. The levels of FPG, fasting plasma insulin （FINS）, tumor necrosis factor （TNF）-α, and interleukin （IL）-6 were measured. HOMA method was used to calculate the insulin resistance index （Ig-IRI）. Immunohistochemistry was used to quantitatively examine the IRS-1 protein and its Ser^307 phosphorylation and Tyr phosphorylation in the gastrocnemius. Western blotting and immunoprecipitation were used to semi-quantitatively examine the changes in contents of IRS-1 and its Serw7 phophorylation and Tyr phosphorylation in the gastrocnemius respectively. Results The survival rates at different time points of the control group were all 100%, all significantly higher than those of the other 2 groups （ all P 〈 0.01 ）, and those of the 10% group were all significantly higher than those of the 30% group （ all P 〈 0.01 ）. The levels of TNF-α and IL-6 of the 10% and 30% groups at different time points were all significantly higher than those of the control group （ all P 〈 0. 01 ）, and those of the 30% group

关 键 词：感染 受体 胰岛素 大鼠 

分 类 号：R587.1[医药卫生—内分泌]