血糖变化对糖尿病大鼠胃排空功能与胃促生长素表达的影响

The effect of blood glucose variation on gastric emptying and ghrelin expression in diabetic rats

目的研究血糖变化对糖尿病大鼠胃排空功能与胃组织胃促生长素(ghrelin)表达的影响,探讨不同病期糖尿病胃排空延迟与胃促生长素表达的关系。方法60只Wistar大鼠随机分为正常对照组(NC组)、糖尿病组(DM组)和胰岛素干预组(INS组)。腹腔注射链脲佐菌素(STZ)制备糖尿病大鼠模型,分别于给药后1和4周用酚红灌胃法检测胃排空;用免疫组化、半定量RT-PCR技术检测大鼠胃组织胃促生长素及其mRNA表达。结果注射STZ 1周后,DM组大鼠的胃排空率、胃促生长素积分吸光度及mRNA表达均明显低于NC组和INS组(P<0.05)。注射STZ 4周后,DM组与INS组大鼠的体质量、胃排空率、胃促生长素积分吸光度均明显低于NC组,而胃促生长素mRNA的表达则高于NC组;DM组与INS组之间差异无统计学意义(P>0.05)。结论短期血糖升高可能通过抑制胃组织胃促生长素表达参与胃排空延迟的发生;而长期高血糖可能通过促进胃促生长素的表达和释放来增加摄食、维持能量平衡。

Objective To study the effect of blood glucose variation on gastric emptying and ghrelin expression in diabetic rats, and to explore the relationship between the delayed gastric emptying and the ghrelin expression in different diabetic stages. Methods Sixty Wistar rats were randomly divided into three groups：a normal control group（NC group）, a diabetes mellitus group （DM group） induced by intraperitoneal injection of streptozotocin （STZ）, and an insulin treated group （INS group）. After one and four weeks the gastric emptying was measured by intragastric administration of phenol red and the exprcssion of gastric ghrelin was determined by immunohistoehemistry and .semi-quantitative RT-PCR. Results After one weck of STZ injection, the gastric emptying, the ghrelin integral optical density and the ghrelin mRNA expression decreased significantly in DM group compared to those in NC group and INS group（P 〈 0.05）. After four weeks of STZ injection, the body weight, the gastric emptying and the ghrelin integral optical density were significant lower in DM group and INS group than thosc in NC group. However, the ghrelin mRNA expression was higher in DM group and INS group than that in NC group. There was no statistical differcnce between DM group and INS group（P 〉 0.05）. Conclusion Short-term hyperglycemia delay gastric cmptying through the reduction of gastric ghrelin expression, while long term hyperglycemia may enhancc the expression and release of gastric ghrelin to stimulate food intake and maintain energy balance.