多甲氧基黄酮对高脂饮食诱导肥胖大鼠糖脂代谢的影响

Effect of polymethoxylated flavonoids on glucose and lipid metabolism in rat model of obesity induced by a high-fat diet

该文采用高脂饮食诱导(HFD)肥胖大鼠,研究多甲氧基黄酮对HFD肥胖大鼠糖、脂代谢的影响,并进一步探讨其改善肥胖的作用和机制。实验选取30只正常SD大鼠,按照体质量随机分为正常组、模型组、依折麦布0.1 mg·kg^(-1)组、多甲氧基黄酮62.5 mg·kg^(-1)组、多甲氧基黄酮125 mg·kg^(-1)组,除正常组给予普通饲料外,其余各组给予高脂饲料,同时各给药组灌胃对应剂量药物。给药期间,定期称量各组大鼠体质量,全自动生化分析仪检测血清中血脂、血糖含量,通过ELISA法检测胰岛稳态指标、血清肥胖因子含量,采用16S rRNA高通量测序检测肠道菌群等指标,称量白色脂肪、棕色脂肪的湿重并计算脏器系数,HE染色观察白色脂肪、棕色脂肪、胰腺的组织形态学,并用免疫组化和Western blot法检测棕色脂肪中相关蛋白表达。结果显示,多甲氧基黄酮可显著降低HFD肥胖大鼠体质量及Lee′s指数,改善血脂水平;降低血糖含量与胰岛素分泌量,提高胰岛素反应活性,缓解胰岛素抵抗;显著调节血清肥胖因子含量;显著降低白色脂肪与棕色脂肪脏器湿重及脏器系数;减小白色脂肪细胞直径,减少棕色脂肪、胰岛细胞中脂肪空泡数。经多甲氧基黄酮干预后,HFD肥胖大鼠肠道菌群多样性增加,在属水平上对HFD肥胖大鼠肠道中与糖脂代谢有关部分的有益菌丰度增加,有害菌减少。此外,多甲氧基黄酮可提高棕色脂肪中葡萄糖转运体4(GLUT4)、磷酸化腺苷酸激活蛋白激酶(p-AMPK)、过氧化物酶体增殖物激活受体γ辅激活因子1α(PGC-1α)、解耦联蛋白1(UCP1)蛋白相对表达。综上所述,多甲氧基黄酮可能通过影响HFD肥胖大鼠体内胰岛素稳态、血清中肥胖因子含量、调节肠道菌群多样性以及棕色脂肪细胞中线粒体代谢相关蛋白的表达,增加机体对糖、脂的利用,从而改善肥胖症状。

This study established a rat model of obesity by using a high-fat diet(HFD)to explore the effect of polymethoxylated flavonoids on glucose and lipid metabolism in the model rats and decipher the role and mechanism of polymethoxylated flavonoids in mitigating obesity.Thirty normal SD rats were selected and randomized into normal,model,ezetimibe(0.1 mg·kg^(-1)),and polymethoxylated flavonoids(62.5 mg·kg^(-1) and 125 mg·kg^(-1))groups based on the body weight.Except the normal group receiving a conventional diet,the other groups received a HFD.Rats were administrated with corresponding doses of drugs by gavage.During the administration period,the body weight of each group of rats was regularly weighed,and the serum lipid and glucose levels were measured by a fully automated biochemical analyzer.Islet homeostasis and serum levels of obesity factors were measured by ELISA.The 16S rRNA high-throughput sequencing was employed to study the gut microbiota.Hematoxylin-eosin staining was employed to observe the histomorphology of white fat,brown fat,and pancreas.After the wet weights of white fat and brown fat were measured,the organ index was calculated.Immunohistochemistry and Western blot were employed to determine the protein levels.The results showed that polymethoxylated flavonoids reduced the body weight and Lee's index and improved blood lipid levels of the model rats.Polymethoxylated flavonoids reduced blood glucose and insulin secretion,increased insulin responsiveness,and alleviated insulin resistance.In addition,polymethoxylated flavonoids regulated the serum levels of obesity factors and reduced the weights and indexes of white fat and brown fat,the diameter of white adipocytes,and the number of fat vacuoles in brown fat and pancreatic islet cells.The intervention with polymethoxylated flavonoids increased the diversity of gut microbiota in the model rats,increasing the beneficial bacteria associated with glucose and lipid metabolism and reduced the harmful bacteria at the genus level.In addition,polymethoxylated flavonoids up-regulated the protein levels of glucose transporter 4(GLUT4),phosphorylated AMP-activated protein kinase(p-AMPK),peroxisome proliferator-activated receptor gamma coactivator-1α(PGC-1α),and uncoupling protein 1(UCP1).In summary,polymethoxylated flavonoids may increase the body utilization of glucose and lipids by regulating the homeostasis of insulin,the serum levels of obesity factors,the diversity of gut microbiota,and the expression of mitochondrial metabolism-related proteins in brown adipocytes,thereby mitigating obesity in rats.