花生油对2型糖尿病大鼠海马CA1区胰岛素受体及胰岛素受体底物表达的影响

目的通过观察2型糖尿病大鼠海马CA1区胰岛素受体(insulin receptor,InsR)、InsR底物-1(insulin receptor substrate-1,IRS-1)、InsR底物-2(IRS-2)表达的改变,研究花生油对2型糖尿病大鼠海马神经元InsR信号转导通路的影响,探讨花生油在防治糖尿病脑病中的作用及相关机制。方法 60只健康雄性SD大鼠随机分为4组:正常对照组(C组)、2型糖尿病组(T2DM组)、2型糖尿病给予2mL花生油组(T2DM+2mL组)及2型糖尿病给予5mL花生油组(T2DM+5mL组)。其中C组大鼠给以正常饮食喂养,其他3组大鼠给以高脂饮食喂养。2个月后,按25mg/kg体质量腹腔注射链脲佐菌素制成2型糖尿病模型,T2DM组、T2DM+2mL组及T2DM+5mL组大鼠继续给予高脂饮食。糖尿病造模1个月后处死全部大鼠,行脑冰冻切片,用免疫组织化学方法检测各组大鼠海马CA1区InsR、IRS-1和IRS-2的表达。结果①T2DM组大鼠海马CA1区InsR表达比C组明显降低(P<0.05),T2DM+5mL组大鼠海马CA1区InsR表达明显高于未给予花生油的T2DM组(P<0.05)。②T2DM组大鼠海马CA1区IRS-1表达显著低于C组(P<0.05),T2DM+2mL组及T2DM+5mL组大鼠海马CA1区IRS-1表达均明显高于未给予花生油的T2DM组(P<0.05)。③T2DM组大鼠海马CA1区IRS-2表达比C组明显降低(P<0.05),T2DM+5mL组大鼠海马CA1区IRS-2表达明显高于未给予花生油的T2DM组(P<0.05)。结论 2型糖尿病大鼠海马CA1区存在胰岛素信号转导通路障碍,这可能是2型糖尿病脑病发生的原因之一。花生油可改善2型糖尿病大鼠海马区内胰岛素信号转导通路相关蛋白的表达,因此,花生油具有一定的保护大鼠糖尿病脑病的作用。

Effect of Peanut oil on Expression of Insulin Receptor and Insulin Receptor Substrates in Hippocampal CA1 Area of Rats with Type 2 Diabetes Mellitus Rats

Objective To study the difference in expression of insulin signal transduction proteins insulin receptor(InsR),insulin receptor substrate-1(IRS-1) and insulin receptor substrate-2(IRS-2) in hippocampal CA1 area of rats with type 2 diabetes mellitus and to investigate the protective effects of peanut oil against diabetic encephalopathy.Methods Sixty healthy male SD rats were assigned into 4 groups randomly:normal control group(C group);type 2 diabetes mellitus group(T2DM group);type 2 diabetes mellitus treated with 2 mL peanut oil group(T2DM+2 mL group) and type 2 diabetes mellitus treated with 5 mL peanut oil group(T2DM+5 mL group).The rats in group C were fed with normal food.Type 2 diabetes mellitus was induced by low dose streptozotocin intraperitoneal injection(25 mg/kg body weight) after feeding with high-fat feed for 2 months.All the rats were sacrificed one month after type 2 diabetes mellitus was induced.The expression of InsR,IRS-1 and IRS-2 in hippocampal CA1 area of rats was studied by immunohistochemical staining.Results The expression of InsR in hippocampal CA1 area of T2DM group decreased significantly compared with that of group C(P<0.05).The expression of InsR in hippocampal CA1 area of T2DM+5 mL group increased significantly compared with that of T2DM group(P<0.05).② The expression of IRS-1 in hippocampal CA1 area of T2DM group decreased significantly compared with that of group C(P<0.05).The expression of IRS-1 in hippocampal CA1 area of T2DM+2 mL group and T2DM+5 mL group increased significantly compared with that of T2DM group(P<0.05).③ The expression of IRS-2 in hippocampal CA1 area of T2DM group decreased significantly compared with that of group C(P<0.05).The expression of IRS-2 in hippocampal CA1 area of T2DM+5 mL group increased significantly compared with that of T2DM group(P<0.05).Conclusion Insulin signal transduction is dysregulated in the hippocampal CA1 area of the type 2 diabetes mellitus rats.This might be one of the reasons that cause diabetic encephalopathy.Peanut oil improves the expression of insulin signal transduction proteins in hippocampal CA1 area of T2DM rats,suggesting that peanut oil might have protective effect against diabetic encephalopathy.