表没食子儿茶素没食子酸酯抑制肥胖大鼠肝中TLR4炎症通路及胰岛素抵抗

Epigallocatechin gallate inhibits the TLR4 inflammatory pathway and insulin resistance in the liver of obese rats

目的探讨表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)对肥胖大鼠肝组织中Toll样受体4(Toll-like receptor 4,TLR4)炎症通路以及胰岛素抵抗的影响。方法将30只雄性SD大鼠随机分为普食组(NC)和高脂饮食组(HFD)。喂养16周后,将高脂饮食组随机分为HFD组与EGCG组继续喂养16周,检测相关代谢指标,测定肝组织甘油三酯含量,并进行油红染色评估肝脂质聚集情况;实时荧光定量PCR检测其肝脏中TLR4和TNF受体相关因子6(TNF receptor associated factor 6,TRAF6)mRNA水平;蛋白质印记检测其肝组织中TLR4信号通路及胰岛素信号通路相关蛋白水平。结果EGCG明显降低大鼠肝脏甘油三酯浓度及脂质聚集、TLR4和TRAF6 mRNA水平,TLR4信号通路相关蛋白水平及胰岛素信号通路相关蛋白水平。结论EGCG抑制肥胖大鼠肝组织中TLR4通路以及胰岛素抵抗。

Objective To explore the effects of epigallocatechin gallate on Toll-like receptor 4(TLR4)signaling pathway and insulin resistance signaling pathway in liver tissue of high fat diet rats.Methods 30 male SD rats were randomly divided into two groups:normal diet group as the control(NC)and high fat diet group(HFD).After 16 weeks of feeding,the HFD group was divided into two groups:HFD group and EGCG group.After another16 weeksof feeding,the levels of metabolic indexes and liver triglyceride(TG)content were examined,Oil Red O staining was used to evaluate the lipid content of liver;the TLR4 and TRAF6 mRNA levels in rat liver were detected by real-time PCR.Western blot was used to detect the protein levels in TLR4 signal pathway and insulin signal transduction pathway in liver tissue of rats.Results EGCG significantly reduced the concentration of TG and lipid accumulation in rat liver,as well as the mRNA levels of TLR4 and TRAF6,TLR4 signaling pathway-associated protein levels and insulin signaling pathway-related protein levels.In addition,the levels of the related proteins in TLR4 signaling pathway and insulin signaling pathway of rat liver tissue were decreased in EGCG group.Conclusion Epigallocatechin gallate suppresses the TLR4 signaling pathway and insulin resistance in the liver of high-fat-diet rats.