能量限制诱导的Sirt1高表达对胰岛β细胞的寿命及胰岛素分泌功能的影响  

Effects of Sirt1 Hyper-expression Induced by Calorie Restriction on Life Span of β Cells and Insulin Secretion

作　　者：朱志宏[1] 陈慎仁[1] 傅玉才[2] 魏炽炬[3] 林超[1] 杨杰华[1] 

机构地区：[1]汕头大学医学院第二附属医院内分泌科 [2]汕头大学医学院细胞衰老实验室,广东汕头515041 [3]汕头大学多学科中心,广东汕头515063

出　　处：《汕头大学医学院学报》2008年第1期24-27,F0003,共5页Journal of Shantou University Medical College

基　　金：广东省自然科学基金资助项目(5008346)

摘　　要：目的:研究能量限制(CR)对大鼠胰岛及胰岛β瘤细胞(NIT-1细胞)寿命和胰岛素分泌功能的影响,为2型糖尿病(T2DM)的发病机制及防治提供实验依据和理论基础。方法:①18月龄健康雄性SD大鼠12只随机分为CR组和对照组,饲养6个月后取胰尾组织进行实验,用免疫组化染色检测胰岛中Sirt1和insulin表达水平,β-半乳糖苷酶(-βGal)染色反映胰岛细胞衰老情况;②NIT-1细胞亦分为对照组和CR组;用RT-PCR、免疫细胞化学染色检测Sirt1的表达变化,用放射免疫及免疫细胞化学检测胰岛素的分泌及表达量的变化,用细胞计数法检测细胞倍增周期的变化。结果:①Sirt1在SD大鼠胰岛及NIT-1细胞的胞浆胞核中均有表达,CR组Sirt1表达量均增加;②CR可使大鼠胰岛-βGal染色阳性率下降、NIT-1细胞倍增周期延长;③CR可使大鼠胰岛及NIT-1细胞胰岛素表达量明显减少,NIT-1细胞胰岛素分泌量亦明显减少。结论:CR通过上调Sirt1基因的表达而延缓β细胞的衰老,CR还通过减少胰岛素的表达及分泌从而减少胰岛素信号的刺激,减轻β细胞的负荷并改善胰岛素的分泌功能,因此CR有利于防止T2DM的发生发展。Objective： To investigate the effects of calorie restriction（CR） on life span and insulin secretion in the pancreatie islet of SD rat and β neoplastic cell（NIT- 1 cell）, and to provide some evidences for pathogenesis and prevention of type 2 Diabetes Mellitus（T2DM）. Methods： ①Twelve male SD rats of 18 months old were randomized into CR and control groups. The caudal end of islet was collected after 6 months of breeding. The expressions of Sirt1 and insulin were detected by immunohistoehemistry, β-galactosidase （β-Gal）was utilized to identify the senescent in pancreatic islets. ②NIT-1 cell was also divided into CR and control groups. The expression of Sirt1 was detected by RT-PCR and Immunocytoehemistry, the secretion and expression of insulin were detected by radioimmunity and immunoeytoehemistry, the cell multiplication cycle was calculated by cytometry. Results： ①Sirt1 hyper-expression was discovered in the CR group, Sirt1 expressed beth in plasma and nucleus. ②The positive ratio of β-Gal was diminised in the islet and the cell multiplication cycle was extended in NIT-1 cell by CR. ③Insulin expression was obviously decreased beth in the islet and NIT- 1 cells treated with CR, besides, the secretion of insulin was also decreased in NIT-1 cell. Conclusion： CR delays the aged proceeding of β cell by enhancing the expression of Sirt1. CR weakens the insulin signal by decreasing the expression and secretion of insulin, and finally softens the burden of the β cell, improves the function of insulin secretion. CR may participate in the generation and development of T2DM.

关 键 词：能量限制 SIRT1 胰岛素 2型糖尿病 

分 类 号：Q7[生物学—分子生物学]