白藜芦醇对妊娠期糖尿病大鼠胰岛细胞氧化应激损伤的保护作用

目的:研究白藜芦醇对妊娠期糖尿病大鼠胰岛细胞氧化应激损伤的保护作用,并探讨其作用机制。方法:首先制备妊娠5 d SD大鼠,通过一次性ip链脲佐菌素(STZ)35 mg·kg~(-1)诱导妊娠期糖尿病大鼠模型,选取100只随机分为妊娠期糖尿病模型组,白藜芦醇(60,120,240 mg·kg~(-1))治疗组和盐酸二甲双胍阳性药组(200 mg·kg~(-1)),每组20只,另取12只妊娠5d SD大鼠作为正常妊娠组,20只同龄非妊娠雌性大鼠作为正常非妊娠组。分别于给药前和给药治疗第7,14天通过血糖仪检测空腹血糖、并采用酶联免疫吸附测定(ELISA)法检测胰岛素水平;治疗满2周后,测定各组大鼠血清中丙二醛(MDA)和活性氧簇(ROS)含量;测定胰腺组织中超氧化物歧化酶(SOD),谷胱甘肽过氧化物酶(GSH-Px),过氧化氢酶(CAT)活性及MDA含量;通过苏木素-伊红(HE)染色观察胰腺组织病理学改变,通过原位末端转移酶标记法(TUNEL)染色观察胰岛细胞凋亡状况并计算凋亡指数(apoptosis index,AI)。结果:与正常非妊娠组比较,正常妊娠组大鼠空腹血糖和胰岛素水平、血清中MDA和ROS含量、胰腺组织中SOD,GSH-Px,CAT活性及MDA含量均无显著性差异,胰腺组织病理学改变及胰岛细胞凋亡状况均无明显差异。与正常妊娠组比较,妊娠期糖尿病模型组大鼠胰岛素水平显著降低、空腹血糖水平显著升高,血清中MDA和ROS含量显著升高,胰腺组织中SOD,GSH-Px,CAT活性显著降低,MDA含量显著升高,胰腺组织病理学改变明显、胰岛细胞凋亡现象突出、胰岛细胞凋亡率显著升高,差异均具有统计学意义(P0.05,P0.01)。与妊娠期糖尿病模型组比较,白藜芦醇(60,120,240 mg·kg~(-1))治疗组大鼠血清中MDA,ROS含量及胰腺组织中MDA含量均显著降低(P0.05,P0.01);白藜芦醇(120,240 mg·kg~(-1))治疗组大鼠胰岛素水平显著升高、血糖水平显著降低(P0.05,P0.01),胰腺组织中SOD,CAT活性显著升高(P0.05,P0.01),胰岛细胞凋亡率显著降低(P0.01);白藜芦醇240 mg·kg~(-1)治疗组大鼠胰腺组织中GSH-Px活性显著升高(P0.05);白藜芦醇各治疗组胰腺组织病理学改变和胰岛细胞凋亡状况均出现不同程度的改善,其中以白藜芦醇240 mg·kg~(-1)治疗组最为显著。结论:白藜芦醇能够有效提高胰岛素分泌水平、降低血糖、改善抗氧化酶活性、提高自由基清除能力、改善胰腺组织病变并抑制胰岛细胞凋亡,提示白藜芦醇对妊娠期糖尿病大鼠胰岛氧化应激损伤具有剂量依赖性的保护作用,并且该作用优于盐酸二甲双胍。

Protective Effects of Resveratrol on Pancreatic Cell Oxidative Injury in Gestational Diabetic Rats

Objective: To investigate the protective effects of resveratrol(Res) on pancreatic cell oxidative injury in gestational diabetic rats. Method: The 100 rats with gestation for five days were injected STZ (35 mg·kg^-1) by intraperitonal to make gestational diabetic model, which were randomly devided into five groups:normal gestation group, gestational diabetic model group, Res(60,120,240 mg·kg^-1) treated groups and metformin hydrochloride 200 mg·kg^-1 treated group, which was 20 expremental animals every group. And selected 20 rats with gestation for five days as normal gestation control group and another 20 rats with no gestation as normal control group. Before the drugs were given and 7, 14 days after treated, the level of plasma glucose and insulin were determined. Two weeks later, the content of malondialdehyde(MDA) and reactive oxygen species(ROS) were detected; the activity of superoxide dismutase(SOD), glutathion peroxidase(GSH-Px), catalase(CAT) in pancreatic tissue were detected, and the content of MDA was also detected; the histopathological changes of pancreatic tissue and pancreatic cells apoptosis were observed, and the apoptosis index were analysised. Result: Compared with normal control group, the level of plasma glucose and insulin of the normal gestation control group was not significantly different, the content of MDA, ROS in serum was not significantly different, the activity of SOD, GSH-Px, CAT and the content of MDA in pancreatic tissue were not significantly different, the level of pancreatic tissue histopathological changes and hepatic cells apoptosis were not significantly different. Compared with the normal gestation control group, the level of plasma glucose in gestational diabetic model group was significantly increased and the level of insulin was significantly decreased(P<0.01); the content of MDA, ROS in serum were significantly increased(P<0.01); the activity of SOD, GSH-Px, CAT in pancreatic tissue were significantly decreased and the content of MDA were significantly increased(P<0.05, P<0.01), the pancreatic tissue histopathological changes and hepatic cells apoptosis were obviously improved, the AI were significantly increased(P<0.01). Compared with the estational diabetic model group, the content of MDA, ROS in serum in Res(60,120,240 mg·kg^-1) treated groups were significantly decreased(P<0.05, P<0.01), and the content of MDA in pancreatic tissue were significantly decreased(P<0.05, P<0.01); the level of plasma glucose in Res(120,240 mg·kg^-1) treated groups were significantly decreased and the level of insulin was significantly increased(P<0.05, P<0.01), the activity of SOD, CAT in pancreatic tissue were significantly increased(P<0.05, P<0.01), the AI of pancreatic cell was significantly decreased (P<0.05, P<0.01); the activity of GSH-Px in pancreatic tissue of Res 240 mg·kg^-1 treated group was significantly increased(P<0.05); and pancreatic tissue histopathological changes and hepatic cells apoptosis were significantly improved, especially the level of Res 240 mg·kg^-1 treated group. Compared with the Metformin hydrochloride treated group, the level of insulin in Res 240 mg·kg^-1 treated group was significantly increased(P<0.05), the content of MDA, ROS in serum were significantly decreased(P<0.05), the activity of SOD, GSH-Px, CAT in pancreatic tissue were significantly increased(P<0.05, P<0.01), the AI was significantly decreased(P<0.01). Conclusion: Res could effectively improve insulin secretion, lowering blood sugar, improve antioxidant ability, reducing the damage of free radical, depress the pancreatic tissue histopathological changes and hepatic cells apoptosis, suggesting that Res had dose-dependent protective effects on pancreatic cell oxidative injury in gestational diabetic rats, and these effects of Res was better than Metformin hydrochloride except lowering blood sugar.