EGCG对高脂饮食诱发的小鼠非酒精性脂肪肝的影响

Effects of epigallocatechin gallate on non-alcoholic fatty liver in mice induced by high-fat diet

目的探讨表没食子儿茶素没食子酸酯(EGCG)对高脂饮食(HFD)诱发的小鼠非酒精性脂肪肝的影响。方法选取60只雄性C57BL/6小鼠,随机分为对照组、EGCG组、HFD组和HFD+EGCG组,分别以普通饲料、普通饲料+EGCG、HFD和HFD+EGCG喂饲。观察各组的腹腔葡萄糖耐量试验(IPGTT)结果、体质量、肝脏和脾脏的湿重、肝脏组织病理学形态、肝组织和血清中三酰甘油(TG)及游离脂肪酸(FFA)水平、肝组织和结肠组织中游离脂肪酸受体2(FFAR2)和FFAR3的mRNA表达水平、肝组织中脂质代谢相关酶及炎性因子的mRNA表达水平。结果喂饲10周时,IPGTT结果显示,HFD组的各时间点血糖水平均较对照组显著升高(P均<0.05);喂饲11周时,与对照组相比,HFD组的体质量、肝脏和脾脏湿重均显著升高(P均<0.05),显微镜下可见肝细胞呈重度脂肪变性,血清和肝组织中TG和FFA水平均显著升高(P均<0.05,P均<0.01),肝组织及结肠组织中FFAR2和FFAR3的mRNA表达水平均显著升高(P均<0.05),肝组织中脂蛋白脂肪酶(LPL)、脂肪酸结合蛋白1(FABP1)、CCL2、TNF-α、IL-6的mRNA表达水平均显著升高(P均<0.05),胆固醇7α-羟化酶(CYP7A1)的mRNA表达水平显著降低(P<0.05)。与HFD组相比,EGCG+HFD组的各时间点血糖水平均显著降低(P均<0.05),体质量、肝脏和脾脏湿重均显著降低(P均<0.05),显微镜下可见肝细胞脂肪变性有明显改善,血清和肝组织中TG及FFA水平均显著降低(P均<0.05,P均<0.01),肝组织和结肠组织中FFAR2和FFAR3的mRNA表达水平均显著降低(P均<0.05),肝组织中LPL、FABP1、CCL2、TNF-α、IL-6的mRNA表达水平均显著降低(P均<0.05),CYP7A1的mRNA表达水平显著升高(P<0.01)。结论HFD能诱发小鼠非酒精性脂肪肝,而EGCG能提高机体的脂质代谢水平及抑制肝脏的炎性反应,从而改善非酒精性脂肪肝小鼠的代谢紊乱。

Objective This paper attempts to study the effect of EGCG on high-fat diet(HFD)-induced non-alcoholic fatty liver disease in mice.Methods Sixty male C57BL/6 mice which were selected and randomly divided into the control group,the epigallocatechin gallate(EGCG)group,the HFD group,and the HFD+EGCG group,were fed with normal chow,common chow+EGCG,HFD,and HFD+EGCG respectively.The results of intraperitoneal glucose tolerance test(IPGTT),body weight,wet weight of liver and spleen,histopathological morphology of liver,levels of triacylglycerol(TG)and free fatty acid(FFA)in liver tissue and serum,the mRNA expression levels of free fatty acid receptor 2(FFAR2)and FFAR3 in liver tissue and colon tissue,and the mRNA expression levels of lipid metabolism-related enzymes and inflammatory factors in liver tissue were observed in each group.Results When fed for 10 weeks,the results of IPGTT show that the blood glucose levels at each time point in the HFD group are significantly higher than that in the control group(P<0.05).When fed for 11 weeks,compared with the control group,the body weight,liver and spleen wet weight of the HFD group are significantly increased(P<0.05),and the hepatocytes show severe steatosis under the microscope,the levels of TG and FFA in serum and liver tissue are significantly increased(P<0.05,P<0.01),the mRNA expression levels of FFAR2 and FFAR3 in liver tissue and colon tissue are significantly increased(P<0.05),the mRNA expression levels of LPL,FABP1,CCL2,TNF-α,and IL-6 in liver tissues are significantly increased(P<0.05),and the mRNA expression level of CYP7A1 is significantly decreased(P<0.05).Compared with the HFD group,the blood glucose levels at each time point,body weight,liver and spleen wet weight in the EGCG+HFD group are significantly decreased(P<0.05),the steatosis of hepatocytes is significantly improved under the microscope,the levels of TG and FFA in serum and liver tissue are significantly reduced(P<0.05,P<0.01),and the mRNA expression levels of FFAR2 and FFAR3 in liver tissue and colon tissue are significantly decreased(P<0.05),the mRNA expression levels of LPL,FABP1,CCL2,TNF-α,and IL-6 in the liver tissue are significantly decreased(P<0.05),and the mRNA expression level of CYP7A1 is significantly increased(P<0.01).Conclusion HFD can induce non-alcoholic fatty liver in mice,while EGCG can improve the lipid metabolism level of the body and relieve the inflammatory response of the liver,thereby improving the metabolic disorder of non-alcoholic fatty liver mice.