清化颗粒对db/db糖尿病小鼠肠道1型味觉受体及其下游信号因子影响的研究

Effect of Qinghua Granules on intestinal type 1 taste receptor and downstream signal factors in db/db diabetic mice

目的观察清化颗粒对db/db糖尿病小鼠肠道1型味觉受体及其下游信号因子的影响。方法将db/db小鼠分为模型组、阳性对照组、中药组,每日分别予等量0.9%NaCl溶液、果糖、清化颗粒灌胃,持续4周。ELISA法分析小鼠血清胰高血糖素样肽-1(GLP-1)和糖化血红蛋白(HbA1c)浓度;qRT-PCR、Western blot法分别检测小鼠回肠组织GLP-1、1型味觉受体亚型(TAS1R1、TAS1R2、TAS1R3)及其下游信号因子转导素α(α-gustducin)、磷脂酶Cβ2(PLCβ2)和瞬时感受器电位阳离子通道蛋白5(TRPM5)mRNA和蛋白表达;免疫组化技术检测空肠组织GLP-1蛋白水平,同时观察小鼠空腹血糖和体质量变化。结果与模型组比较,中药组可提高小鼠血清GLP-1的血清浓度、回肠组织GLP-1 mRNA和蛋白表达,上调小鼠回肠组织TAS1R2及其下游信号因子PLCβ2、TRPM5 mRNA和蛋白表达(P<0.05),上调小鼠回肠组织TAS1R1及下游信号因子α-gustducin mRNA和蛋白水平(P<0.05)。在GLP-1外周效应方面,与模型组比较,中药组小鼠空腹血糖、体质量上升幅度及HbA1c水平降低(P<0.05)。结论清化颗粒能通过激活1型味觉受体通路,促进肠道L细胞合成并分泌GLP-1,从而发挥GLP-1调节血糖稳态和降低体质量的外周效应。

Objective To observe the effect of Qinghua Granules on intestinal type 1 taste receptor and its downstream signal factors in db/db diabetic mice.Methods The db/db mice were divided into the model group,the positive control group and Qinghua Granules group.The mice were given respectively the same amount of 0.9%NaCl solution,fructose and Qinghua Granules daily for 4 weeks.The concentrations of serum glucagon-like peptide-1(GLP-1)and glycosylated hemoglobin(HbA1c)were analyzed by ELISA,and the expressions of GLP-1,type 1 taste receptor(TAS1R1,TAS1R2,TAS1R3)and its downstream signal factorsα-gustducin,phospholipase Cβ2(PLCβ2)and transient receptor potential cation channel protein 5(TRPM5)mRNA and protein in ileal tissue of mice were detected by qRT-PCR and Western blot respectively.The level of GLP-1 protein in jejunal tissue was detected by immunohistochemical technique,and the changes of fasting blood glucose and body mass were observed at the same time.Results Compared with the model group,the Qinghua Granules group could increase the serum concentration of GLP-1,GLP-1 mRNA and protein in ileal tissue,up-regulate the expression of TAS1R2 and its downstream signal factors including PLCβ2,TRPM5 mRNA and protein in mouse ileum(P<0.05),and up-regulate the levels of TAS1R1 and downstream signal factorα-gustducin mRNA and protein in ileal tissue of mice(P<0.05).In terms of the peripheral effect of GLP-1,compared with the model group,the fasting blood glucose,the increase of body mass and the level of HbA1c in the Qinghua Granules group were significantly lower than those in the model group(P<0.05).Conclusion Qinghua Granules can promote intestinal L cells to synthesize and secrete GLP-1 by activating type 1taste receptor pathway,thus exerting the peripheral effect of GLP-1 in regulating blood glucose homeostasis and reducing body mass.