胰岛素抵抗大鼠血糖正常阶段β细胞超微结构改变

Ultrastructural changes of beta cells in insulin-resistant rats at normal blood glucose stage

目的 观察胰岛素抵抗 (IR)大鼠血糖正常阶段的 β细胞超微结构改变。 方法 高糖饲料喂养SD大鼠 12周 ,复制IR模型。普通饲料喂养的SD大鼠为正常对照。透射电镜观察胰岛β细胞超微结构。 结果 与正常大鼠相比 ,IR大鼠收缩压 (SBP)、血清三酰甘油 (TG)、低密度脂蛋白胆固醇 (LDL c)、游离脂肪酸 (FFA)、胰岛素 (Ins)水平均明显升高 (P值均 <0 .0 1) ,胰岛素敏感指数 (ISI)、血清HDL c降低 (P值均 <0 .0 1)。空腹血糖 (FBG)、餐后 2h血糖 (PBG2h)在正常范围。电镜观察IR大鼠 β细胞可见凋亡的早期改变 ,细胞浆内脂质沉积以及细胞核和细胞器的病理改变。结论 高糖膳食诱发的IR大鼠在血糖正常阶段已存在

Objective To observe the ultrastructural changes of beta cells in insulin resistant rats at normal blood glucose stage. Methods Insulin resistant rats(IR) model( n =10) was reproduced from 6～8 week old Sprague Dawley(SD) rats by high glucose diet (70% calories from glucose )for 12 weeks. Normal diet SD rats ( n =10) were taken as the control group(CN). Ultrastructural changes of beta cells were observed with transmission electron microscope(TEM). Results Systolic blood pressure(SBP) and serum triglyceride(TG), low density lipoprotein(LDL c) ,free fatty acid(FFA),insulin level in IR group were higher than those in CN(all P <0.01).Serum high density lipoprotein(HDL c) and insulin sensitive index(ISI) were lower in IR group than in CN group(both P <0.01).Fasting blood glucose(FBG) and postprandial blood glucose(PBG2h) in IR group were within normal range. The beta cells in IR group showed early apoptosis, cytoplasmic fat accumulation as well as pathologic changes of nuclei and organelles. Conclusion In high glucose induced IR rats, the beta cells show abnormal apoptosis and ultrastructural changes of β cells at normal blood glucose stage.