西格列汀对糖尿病肾病大鼠细胞外信号调节激酶1/2信号通路的影响

Effect of Sitagliptin on ERK1/2 signal pathway in rats with diabetic nephropathy

目的观察西格列汀对糖尿病肾病(DN)大鼠肾脏的保护作用及对细胞外信号调节激酶1/2(ERK1/2)信号通路的影响。方法 40只雄性Wistar大鼠随机分为正常对照组(NC)、DN模型组(DN)、西格列汀小剂量干预组(ST_1)、西格列汀大剂量干预组(ST_2)。第16周末处死大鼠,检测血糖、HbA_1c、UAER、Scr,肌酐清除率(Ccr)及肾重指数;光镜观察肾组织病理变化;免疫组织化学法及RTPCR检测肾脏足细胞标记蛋白(Podocalyxin)和ERK1/2蛋白及基因的表达。结果(1)16周末,ST_1组、ST_2组与DN组比较,FPG、UAER、Scr、HbA_1c和肾重指数下降(P<0.05),Ccr升高(P<0.05);ST_2组上述变化更明显(P<0.05)。(2)与DN组比较,ST_1组和ST_2组肾小球病理损伤有所改善;且ST_2组较ST_1组改善更明显。(3)与DN组比较,免疫组织化学显示,ST_1组和ST_2组肾小球Podocalyxin的表达增加[(0.235±0.012)vs(0.456±0.024)vs(0.678±0.021),P<0.05];ERK1/2表达降低[(8.021±0.231)vs(6.121±0.021)vs(4.098±0.130),P<0.05],与ST_1组比较,ST_2组上述变化更明显(P<0.01)。RT-PCR检测Podocalyxin和ERK1/2基因表达趋势与免疫组织化学表达一致。结论西格列汀可延缓DN的进展,其机制与抑制ERK1/2信号通路的活化有关。

Objective To investigate the protective effect of DPP-Ⅳ inhibitor Sitagliptin on kidney and to explore the impact of Sitagliptin on ERK1/2 signaling pathways in rats with diabetic nephropathy （DN）. Methods 40 male wistar rats were randomly divided into normal control group （NC）, diabetic model group （DN）, Sitagliptin small-dose intervention group （ST]）, Sitagliptin high-dose intervention group （ST2）. At the end of the 16 weeks the rats were put to death. Blood glucose （BG）,glycosylated hemoglobin （HbA1 c）,Urinary albumin excretion rate （UAER）and serum creatinine （Scr） were measured. Creatinine clearance （Ccr） and kidney hypertrophy index were calculated. The pathological changes in kidney tissue were observed by light microscope. Immunohistochemical method and real-time PCR were used to detect protein and mRNA expression of podocalyxin glomerular podocyte factor and ERK1/2. Results （1）At the end of 16 weeks,compared with DN group,the levels of BG,UAER, and Scr, HbAlc and kidney hypertrophy index were significantly decreased in ST1 and ST2 group （P〈0.05）, and the levels of Ccr were increased in Sitagliptin group （P〈0. 05）,especially in ST2 group （P〈0.05）. （2）Compared with DN group, glomerular pathological lesions were improved in Sitagliptin intervention group. （3） Compared with DN, immunohistochemical analysis showed that the expression of podocalyxin were increased significantly in ST1 and ST2 group than that in DN group [（0. 456±0. 024） vs （0. 678±0. 021）vs （0. 235±0. 012）（P〈0. 05）], and the expressions of ERK1/2 were decreased significantly [-（6. 121± 0. 021） vs （4. 098±0. 130） vs （8. 021 ±0. 231）（P〈0.05）]. Real-time PCR detection of podocalyxin and ERK gene expression was consistent with the trend of protein expression. Conclusion Sitagliptin may delay the progress of DN and inhibit the activity of ERK1/2 signaling pathways.