南苜蓿总皂苷对2型糖尿病大鼠糖脂代谢及胰岛细胞的作用

Effects of TSMP on glucose and fat metabolism as well as functions of pancreatic islet cells in type 2 diabetic rats

目的:观察南苜蓿总皂苷(TSMP)对2型糖尿病(T2DM)大鼠血糖、血脂、氧化应激的影响。方法:采用高糖高脂饲料喂养4周加小剂量的链脲佐菌素(30 mg·kg-1)的方法建立2型糖尿病大鼠模型,将50只模型大鼠随机分为模型组,二甲双胍组(0.2 g·kg-1),南苜蓿总皂苷高剂量组(2.8 g·kg-1)、中剂量组(1.4 g·kg-1)、低剂量组(0.7 g·kg-1),连续灌胃4周,末次给药后测定空腹血糖(FBG)、总胆固醇(TCH)、三酰甘油(TG)、低密度脂蛋白(LDL-C)、高密度脂蛋白(HDL-C)、空腹胰岛素(FINS)、糖化血红蛋白(HbA1c)、丙二醛(MDA)、超氧化物岐化酶(SOD),免疫组化法观察胰岛素和胰高血糖素的表达。结果:与模型组比较,南苜蓿总皂苷2.8,1.4 g·kg-1能显著降低实验性2型糖尿病大鼠给药后7,8周的FBG水平(P<0.01或P<0.05);降低TCH、TG、LDL-C的水平(P<0.01或P<0.05),升高HDL-C的水平含量(P<0.05);降低FINS和HbA1c水平(P<0.01或P<0.05);降低MDA含量(P<0.01);升高SOD含量(P<0.01);增加胰岛素阳性表达,减少胰高血糖素阳性表达。结论:南苜蓿总皂苷对2型糖尿病模型大鼠具有降低血糖,调节血脂,抗氧化,保护胰腺功能的作用。

OBJECTIVE To observe effects of total saponins from Medicago polymorpha（TSMP）on blood glucose,lipid and antioxidant activity,as well as improvement of pancreatic islet cell functions.METHODS Rat models of type 2 diabetes were established by feeding rats with high glucose and fat diets and intraperitoneally injecting STZ30 mg·kg^-1.Rats were divided into five groups：control,model,metformin,TSMP2.8 g·kg^-1,1.4 g·kg^-1 and 0.7 g·kg^-1,and all rats were medicated for four weeks.At the end of medication,blood samples were collected to determine fasted blood glucose（FBG）,total cholesterol（TCH）,triglyceride（TG）,high density lipoprotein（HDL-C）,low density lipoprotein（LDL-C）,fasted serum insulin（FINS）,HbA1 c,malondialdehyde（MDA）and superoxide dismutase（SOD）.Insulin and glucagon protein expression were detected by immunohistochemistry.RESULTS Compared with model group,TSMP1.4 g·kg^-1 decreased FBG level（P〈0.01 or P〈0.05）,contents of TCH,TG and LDL-C（P〈0.01 or P〈0.05）,FINS and HbA1 c levels（P〈0.01 or P〈0.05）,content of MDA（P〈0.01）.TSMP 1.4 g·kg^-1 increased contents of SOD and HDL-C.Insulin immunoreactive cells decreased,but glucagon increased.CONCLUSION TSMP can decrease blood glucose,adjust blood lipids,resist oxidization and protect pancreatic functions.