糖尿病大鼠肠道甜味受体表达及肠促胰素分泌的变化

Expression of intestinal sweet taste receptors and incretin secretion in diabetic rats

目的观察糖尿病大鼠回肠甜味受体(STRs)表达及胃肠激素分泌的变化。方法选取健康对照组(CON组)SD大鼠、Zucker肥胖糖尿病大鼠(ZDF组)和链脲佐菌素诱导的1型糖尿病大鼠(STZ组),每组各7只。三组大鼠均行胃内葡萄糖耐量实验,期间采集血样测量血糖,分离血浆检测胰岛素和胰高血糖素样肽-1(GLP-1)浓度。1周后,处死大鼠取回肠组织采用RT-PCR检测STRs的表达。结果与CON组和STZ组比较,ZDF组回肠T1R3及α-味转导素表达均下调(P<0.05)。在0、15、30、60、120 min时,STZ组血糖水平高于CON组及ZDF组(P<0.01)。在0、15、30、60、120 min时,ZDF组血清胰岛素和GLP-1水平高于CON组及STZ组大鼠(P<0.05,P<0.01)。结论 ZDF大鼠回肠T1R3及其下游信号分子表达失调,肠道STRs表达可能与葡萄糖代谢有关,其机制仍需要进一步研究。

Objective To observe the expression of sweet taste receptors（STRs） and downstream molecules in the ileum and gut hormone secretion in diabetic rats. Methods SD rats（CON group）, zucker diabetic fatty（ZDF group） rats and STZ-induced diabetic rats（STZ group） were involved in this study（n = 7）. The rats in each group were received an intragastric glucose tolerance test. Blood samples were taken for measurement of blood glucose, plasma insulin and GLP-1 concentrations. One week later, small intestinal tissue was collected and expression of STRs was detected by RT-PCR. Results T1 R3 and α-gustducin in the ileum of ZDF group were down-regulated than those of CON and STZ group（P〈0.05）. Fasting and postprandial glucose concentrations in STZ group were higher than CON and ZDF group at 0, 15, 30, 60, 120 min（P〈0.01）. Fasting and postprandial plasma insulin and GLP-1 levels were higher in ZDF group than CON and STZ group（P〈0.05 or P〈0.01）. Conclusion The ileum expression of T1 R3 and its downstream signaling molecules is disordered in ZDF rats, indicating that the expression of intestinal STRs is related to glucose metabolism. The mechanism underneath it still needs further investigation.