白藜芦醇对db/db小鼠胰岛β细胞功能的影响

Effects of Resveratrol on pancreatic islet beta cell function in db/db mice

目的观察白藜芦醇对db/db小鼠胰岛β细胞的作用并探讨其可能机制。方法取12只db/db小鼠,随机分为糖尿病(DM)组和白藜芦醇干预组,每组各6只,另设对照(Con)组小鼠6只。干预4周后,比较各组OGTT后血糖水平,免疫组织化学分析胰岛中3-磷酸肌醇依赖性蛋白激酶1(PDK-1)蛋白表达量的改变。体外培养小鼠胰岛细胞株MIN6细胞并分为正常葡萄糖(NG)组、高糖(HG)组、高糖+白藜芦醇(HG+Res)组、高糖+白藜芦醇+PI3K特异性抑制剂Wortmannin(HG+Res+Wo)组。Western blot测定4组细胞PDK-1、磷酸化蛋白激酶B(p-AKt)水平,CCK-8法和流式细胞仪检测MIN6细胞增殖、凋亡率;ELISA测定上清液中胰岛素水平。结果与DM组比较,白藜芦醇干预组OGTT血糖曲线下面积下降(P<0.05)、胰岛细胞PDK-1蛋白表达增加[阳性率(0.57±0.32)%vs(1.74±0.47)%,P<0.01];与HG组比较,白藜芦醇干预后MIN6细胞中PDK-1、p-Akt蛋白增加、上清液中胰岛素水平增加[(124.95±5.37)vs(181.19±30.77)pmol/L]、细胞增殖(D值)增加[(0.71±0.10)vs(1.02±0.09)]、凋亡率下降[(19.3±2.1)%vs(11.2±1.4)%](P<0.01);与HG+Res组比较,HG+Res+Wo组MIN6细胞PDK-1表达、Akt磷酸化水平减低,上清液中胰岛素水平及细胞增殖下降、凋亡率增加(P<0.05)。结论白藜芦醇可能通过激活胰岛β细胞PDK-1/Akt通路、改善胰岛β细胞功能。

Objective To investigate the effect of Resveratrol on pancreatic islet beta cells in db/db mice and its possible mechanism. Methods A total of 12 db/db mice were randomly assigned to diabetes mellitus（DM）group（n=6）or Resveratrol treated group（n=6）while db/m mice were enrolledas control group（Con,n=6）.After 4 weeks of intervention,the oral glucose tolerance test（OGTT）were performed and the expression of 3-phosphoinositide dependent protein kinase-1（PDK-1）protein in islet were analyzed by immunohistochemical staining in all thethree groups.The MIN6 cell lines were cultured and divided into four groups：normal glucose group（NG）,high glucose group（HG）,high glucose ＋Resveratrol group（HG＋Res）,and high glucose＋resveratrol＋ PI3 Kinhibitor Wortmannin group（HG＋Res＋Wo）.The protein levels of PDK-1,phosphorylated protein kinase B（p-Akt）were measuredby western blot.The proliferation and apoptosis of MIN6 cells were tested by CCK-8 assay and flow cytometry.The insulin level in cell supernatant was measured by ELISA. Results The OGTT blood glucose area under the curve decreased significantly in HG＋Res group than in HG group（P〈0.05）.The expression of PDK-1 protein in islet beta cells increased in HG＋Res group than in HG group [positive rate（0.57±0.32）%vs（1.74±0.47）%,P〈0.01].The expression of PDK-1,p-Akt protein increased,the insulin levels in cell supernatant [（124.95±5.37）vs（181.19±30.77）pmol/L]and the cell proliferation [（0.71 ± 0.10）vs（1.02 ± 0.09）]also increased,while the apoptosis rate decreased[（19.3±2.1）%vs（11.2±1.4）%]in HG＋Res group than in HG group（P〈0.01）.The expression of PDK-1 and p-Akt protein,the insulin level and cell proliferation decreased and the cell apoptosis rate increased in HG＋Res＋Wo group than in HG＋Res group（P〈0.05）. Conclusion Resveratrol may improve islet beta cell function by activating the PDK-1/Akt pathway in pancreatic beta cells.