RNA干扰特异性阻断胰岛局部血管紧张素Ⅱ1型受体对第一相胰岛素分泌的影响  

Effect of small interfering RNA-mediated angiotensin Ⅱ type 1 receptor knockdown on first-phase insulin secretion in isolated diabetic rat islets

作　　者：易秋艳[1] 刘艳清[2] 张珍[2] 刘春燕[1] 卢斌[1] 邵加庆[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内分泌科,江苏南京210002 [2]南方医科大学南京临床学院南京军区南京总医院内分泌科,江苏南京210002

出　　处：《南方医科大学学报》2015年第5期671-676,共6页Journal of Southern Medical University

基　　金：国家自然科学基金(81471018);江苏省医学重点人才项目(RC2011138);江苏省自然科学基金(BK2012781)~~

摘　　要：目的：观察RNA干扰技术阻断胰岛局部血管紧张素II 1型受体（AT1R）表达后db/db小鼠胰岛第一相胰岛素分泌的变化并探讨其潜在机制。方法分离db/db和db/m小鼠的胰岛并检测AT1R mRNA和蛋白的表达。构建针对小鼠AT1R基因的RNA干扰重组腺病毒（Ad-siAT1R）及含对照序列的重组腺病毒（Ad-siControl）。将分离培养的db/db小鼠胰岛细胞分为三组：Ad-siAT1R感染组、Ad-siControl感染组、空白对照组。腺病毒感染后继续培养胰岛细胞72 h。检测各组AT1R、GLUT-2及葡萄糖激酶（GCK）的表达，并用胰岛灌流系统检测胰岛素动态分泌。结果 db/db小鼠胰岛中AT1R mRNA和蛋白表达水平比db/m小鼠胰岛高2倍左右（P〈0.05）。腺病毒感染后，Ad-siAT1R组较Ad-siControl组胰岛AT1R mRNA表达水平下降75%，蛋白表达水平下降65%，而GLUT-2及GCK表达水平分别升高190%、121%（均P〈0.05）。胰岛灌流显示：空白对照组和Ad-siControl组小鼠的胰岛素第一相分泌显著下降，仅为基础水平的1.8倍；而Ad-siAT1R组在高糖负荷后1~2 min即达到最高峰值140 mU/L，为基础水平的2.8倍，表明第一相胰岛素分泌明显改善。结论 RNA干扰特异性阻断胰岛局部AT1R表达可上调GLUT-2及GCK表达，恢复第一相胰岛素分泌，这可能是AT1R阻滞剂改善胰岛分泌功能的机制之一。Objective To investigate the effects of angiotensin II type 1 receptor （AT1R） knockdown on the first-phase insulin secretion in isolated islets of db/db mice and explore the possible mechanisms. Methods Islets were isolated from db/db and db/m mice and the expression level of AT1R in the islets was assayed. A recombinant adenovirus containing siRNA targeting AT1R （Ad-siAT1R） and a recombinant adenovirus with nonspecific siRNA （Ad-siControl） were constructed to infect the isolated islets for 72 h. AT1R, GLUT-2, and GCK expressions in the islets were investigated and islet perifusion was performed to evaluate the kinetics of insulin release. Results The expression level of AT1R in the isolated islets from db/db mice was twice that of islets from db/m mice. The islets treated with Ad-siAT1R showed significantly decreased AT1R mRNA and protein levels and significantly increased expression of GLUT-2 （by 190%） and GCK （by 121%） compared to those treated with Ad-siControl （P〈0.05）. In response to stimulation with 16.7 mmol/L glucose, the first-phase insulin secretion was impaired in both Ad-siControl group and mock infected group with the peak insulin levels only 1.8 times of the basal level; the first-phase insulin secretion was markedly improved in islets treated with Ad-siAT1R, with a peak insulin level reaching 2.8 times of the basal level. Conclusions In isolated islets of db/db mice, selective AT1R inhibition can restore the first phase insulin secretion by up-regulating GLUT-2 and GCK, which may be one of the potential mechanisms by which AT1R blockers improve insulin secretion function.

关 键 词：RNA干扰 肾素-血管紧张素系统 血管紧张素II 1型受体 第一相胰岛素分泌 

分 类 号：R587.1[医药卫生—内分泌]