泽泻多糖对2型糖尿病大鼠胰岛素抵抗及脂代谢紊乱的改善作用及机制研究

Improvement Effects of Alisma orientalis Polysaccharide on Insulin Resistance and Lipid Metabolism Disorder in Type 2 Diabetes Mellitus Rats and Its Mechanism Study

目的:考察泽泻多糖对2型糖尿病(T2DM)大鼠胰岛素抵抗及脂代谢紊乱的影响及可能机制。方法:采用高脂饮食饲养联合腹腔注射链脲佐菌素(30 mg/kg)法建立T2DM大鼠模型。将造模成功的50只大鼠随机分为模型组(生理盐水)、格列本脲组(阳性对照,25 mg/kg)和泽泻多糖高、中、低剂量组(400、200、100 mg/kg),每组10只;另选10只正常大鼠作为正常对照组(生理盐水)。各组均灌胃给药,每天1次,连续6周。给药5周后进行糖耐量实验,分别检测腹腔注射2 g/kg葡萄糖溶液后0、30、60、90、120 min大鼠空腹血糖(FBG)水平。给药6周后,检测大鼠血清中空腹胰岛素(FINS)、FBG水平并计算胰岛素抵抗指数(HOMA-IR)和胰岛素敏感指数(ISI);检测大鼠血清中游离脂肪酸(FFA)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、三酰甘油(TG)、总胆固醇(TC)水平和肝组织中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)水平。结果:与正常对照组比较,糖耐量实验中,模型组大鼠0~120 min的FBG水平均升高;给药6周后,模型组大鼠血清中FINS、LDL-C水平和ISI以及肝组织中SOD、GSH-Px水平均降低,差异均有统计学意义(P<0.05)。与模型组比较,除泽泻多糖低剂量组大鼠HOMA-IR和血清中LDL-C、HDL-C水平改善不显著外(P>0.05),其余各给药组大鼠各指标均显著改善(P<0.05)。结论:泽泻多糖可能通过抗氧化作用来改善T2DM大鼠胰岛素抵抗及脂代谢紊乱。

OBJECTIVE：To investigate the effects of Alisma orientalis polysaccharides on the insulin resistance and lipid metab- olism disorder in type 2 diabetes mellitus （T2DM） rats and its possible mechanism. METHODS： T2DM rat model was induced by high fat diet combined with intraperitoneal injection of streptozotocin （30 mg/kg）. 50 model rats were randomly divided into model group （normal saline）, glibenclamide group （positive control, 25 mg/kg） and A. orientalis polysaccharide high-dose, medium-dose and low-dose groups （400, 200, 100 mg/kg）, with 10 rats in each group. Other 10 normal rats were included in normal control group （normal saline）. All groups were given drugs ig, once a day, for consecutive 6 weeks. After 5 weeks of administration, the glucose tolerance test was conducted. Fasting blood glucose （FBG） levels were measured in rats 0, 30, 60, 90, 120 min after in- traperitoneal injection of 2 g/kg Glucose solution, respectively. After 6 weeks of administration, serum levels of FINS and FBG were measured, and HOMA-IR and insulin sensitivity index （ISI） were calculated; serum levels of FFA, LDL-C, HDL-C, TG and TC were detected, and the levels of SOD, GSH-Px and MDA in liver tissue were detected. RESULTS： Compared with normal control group, FBG levels of rats in model group at 0-120 min were increased significantly in glucose tolerance test. After 6 weeks of administration, the serum levels of F1NS, LDL-C and ISI, and the levels of SOD and GSH-Px in the liver tissue of the model group were decreased, and the differences were statistically significant （P〈0.05）. Compared with model group, each index of oth- er administration group were improved significantly （P〈0.05）, except that HOMA-IR, the serum levels of LDL-C and HDL-C were not significantly improved in A. orientalis polysaccharide low-dose group （P〉0.05）. CONCLUSIONS： A. orientalis polysac- charide can improve insulin resistance and lipid metabolism disorder in T2DM rats through antioxidant effect.