南方医科大学学报

南方医科大学学报 ›› 2015, Vol. 35 ›› Issue (05): 671-.

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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

易秋艳，刘艳清，张珍，刘春燕，卢斌，邵加庆   

  • 出版日期:2015-05-20 发布日期:2015-05-20

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

  • Online:2015-05-20 Published:2015-05-20

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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。

Abstract: 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.