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

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（30mg·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（0.2g·kg^-1），南苜蓿总皂苷高剂量组（2.8g·kg^-1）、中剂量组（1.4g·kg^-1）、低剂量组（0.7g·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2.8，1.4g·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。

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

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 STZ 30 mg·kg^-1. Rats were divided into five groups: control, model, metformin, TSMP 2.8 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), HbA1c, malondialdehyde (MDA) and superoxide dismutase (SOD). Insulin and glucagon protein expression were detected by immunohistochemistry.RESULTS Compared with model group, TSMP 1.4 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 HbA1c 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.