妊娠期糖尿病大鼠胰腺组织中p-PERK、ATF4和CHOP蛋白的表达

Expressions of p-PERK,ATF4 and CHOP protein in rat model of gestational diabetes mellitus

目的:探讨磷酸化蛋白激酶R样内质网激酶(p-PERK)、C/EBP同源蛋白(CHOP)、ATF4蛋白的表达与高脂高糖诱导的妊娠期糖尿病大鼠胰岛β细胞凋亡的关系。方法:30只雌性SD大鼠分为模型组(高脂高糖喂养)和对照组(普食喂养),每组15只,妊娠第21天行静脉糖耐量及静脉胰岛素释放实验;取胰腺组织行HE染色和病理组织学观察,TUNEL法检测胰岛β细胞凋亡情况,免疫组化法检测胰腺组织中p-PERK蛋白的表达,Western blot检测胰腺组织中ATF4及CHOP蛋白的表达。结果:模型组大鼠第一时相胰岛素分泌受抑制,胰岛素分泌峰值延迟;病理组织学可见模型组大鼠胰岛形态欠规则,数目减少不明显,部分细胞空泡变性,毛细血管扩张、充血,有出血发生。模型组大鼠胰腺组织细胞凋亡率较对照组升高(t=21.164,P<0.001)。与对照相比,模型组大鼠胰腺组织p-PERK、ATF4及CHOP蛋白表达水平明显升高(t=44.178、49.249、39.664,P<0.001);模型组大鼠胰腺组织中ATF4与CHOP蛋白的表达呈正相关(r=0.810,P=0.004)。结论:PERK、ATF4可能参与妊娠期糖尿病大鼠胰岛β细胞凋亡的发生。

Aim： To investigate the relationship between the activation of p-PERK,ATF4 and CHOP protein and isletβ cell apoptosis of pregnant rats with high sucrose and fat diet. Methods： Thirty healthy female SD rats were allocated into two groups randomly： control group（n = 15） and gestational diabetes mellitus（GDM） model group（n = 15）. Twenty-one days after gestation,intravenous glucose tolerance test（IVGTT） and intravenous insulin releasing test（IVIRT） were per-formed;the pancreas was removed for examination of morphological and ultra structural changes; the islet β cell apoptosis index was calculated by TUNEL;the expression of p-PERK in pancreatic tissue was analyzed by immunohistochemistry;the expressions of ATF4 and CHOP protein were analyzed by Western blot. Results： The first-phase insulin secretion of rats in the GDM model group was inhibited,and the insulin secretion peak was delayed;the islet morphology was not regular,the reducing was not obvious,some cells degenerated,blood capillaries dilated,and there was hyperemia or bleeding occurred in the GDM model group by means of HE staining;the apoptotic rate increased in the GDM model group（t = 21. 164,P 〈0. 001）;compared with control group,the level of p-PERK,ATF4,and CHOP in pancreatic tissue increased significantly in the GDM model group（t = 44. 178,49. 249,and 39. 664,P 〈 0. 05）. Correlation analysis showed that the expression level of ATF4 was positively correlated with CHOP protein in islet tissue from rats in the GDM model group（ r = 0. 810,P =0. 004）. Conclusion： The activation expressions of ATF4 and PERK protein may participate in apoptosis of pancreatic βcells in GDM rats induced by high sucrose and fat diet.