2型糖尿病胃促生长素受体的表达与胃排空关系

Association of gastric emptying with expression of ghrelin receptor in model of rats with type 2 diabetes mellitus

目的探讨2型糖尿病大鼠下丘脑和胃组织中胃促生长素（ghrelin）受体（GHSR）表达变化与胃排空的关系。方法将大鼠分为糖尿病组、单纯肥胖组和对照组。糖尿病组和单纯肥胖组大鼠给予高糖和高脂饮食，糖尿病组8周后注射小剂量链脲佐菌素（STZ）。检测各组大鼠体重、空腹血糖和胰岛素水平，并计算胰岛素抵抗指数。酚红灌胃法检测胃排空，实时定量荧光RT—PCR测定下丘脑和胃组织中GHSRmRNA表达。结果糖尿病组和单纯肥胖组饲养8周后，体重和胰岛素水平较对照组明显升高（P〈0．01），血糖较对照组增高，但差异无统计学意义（P〉0．05）。注射STZ后，糖尿病组胰岛素水平显著下降，血糖水平明显升高（P〈0．05）。糖尿病组和单纯肥胖组液体胃排空低于对照组（P〈0．05），下丘脑和胃组织GHSRmRNA表达均明显下降（P〈0．05），并与胃排空下降呈正相关（P〈0．05）。结论2型糖尿病大鼠下丘脑和胃组织中GHSRmRNA的表达下降，降低了胃促生长素的促胃肠动力作用，从而有可能参与了糖尿病胃排空的延迟。可能与糖尿病冒排奉瞳碍右关．

Objective To investigate the relationship between expression of ghrelin receptor and gastric emptying. Methods The rats were divided into normal control group, simple obesity group and type 2 diabetes group. The rats in simple obesity group and type 2 diabetes group were given high- glucose and high-fat diet. At the end of 8th week, the rats in type 2 diabetes group were injected with STZ into peritoneal cavity. The body weight and the levels of blood glucose and insulin were detected. Gastric emptying was measured by intragastrie administration of phenolred. Moreover, real-time PCR was used to examine the expression of ghrelin receptor mRNA in the hypotbalamus and gastric tissue. Results At the end of 8th week, the body weight and insulin level in type 2 diabetes and simple obesity groups were increased significantly compared with normal control group （P〈0.01）, whereas the increase of blood glucose level in type 2 diabetes and simple obesity groups was no statistical difference with that of normal eontrol group （P〉0.05）. The insulin level was decreased in type 2 diabetes group after injection of STZ, and blood glucose level was increased significantly （P〈0.01）. Gastric emptying was delayed in type 2 diabetes and simple obesity groups （P〈0.05）. The mRNA expression of ghrelin receptor in hypothalamus and gastric tissue of type 2 diabetes rats was decreased, which showed a positive correlation with decrease of gastric emptying （P〈0.05）. Conclusion The decreased expression of ghrelin receptor mRNA in hypothalamus and gastric tissue may involve in the delayed gastric emptying by reducing the effect of ghrelin.