Therapeutic Effects And Mechanisms Of Stilbene Glycoside On Non-Alcoholic Fatty Liver Disease In Zebrafish

Objective:Explore the therapeutic effects and mechanisms of stilbene glucoside（2,3,5,4’-tetrahydroxystilbene-2-O-β-D-glucoside,TSG,trans structures）on non-alcoholic fatty liver disease（NAFLD）in larval zebrafish,which provides a new scientific basis for the development and utilization of TSG.Method:Five-day post fertilization wild-type AB zebrafish was randomly divided into normal cholesterol-diet group（NCD）,high cholesterol-diet group（HCD）and stilbene glucoside groups（TSG）.NCD group was fed with normal diet,HCD group was fed with 5%high cholesterol diet,and TSG groups were fed with 5%high cholesterol diet and then treated with different concentrations of TSG（25,50,100μg/m L）.After continuous feeding for 10 days,the survival rate,body weight and body length of larval zebrafish were observed.The lipid accumulation in the liver was investigated by frozen oil red O staining.The body fat content was investigated by total cholesterol（TC）,triglyceride（TG）and high-density lipoprotein cholesterol（HDL-c）kits.The liver function of larval zebrafish was evaluated by alanine aminotransferase（ALT）and aspartate aminotransferase（AST）kits.Hematoxylin and eosin staining was used to examine the pathological changes of hepatic tissue in larval zebrafish.The H₂O₂content was detected by reactive oxygen species（ROS）fluorescence probe.Superoxide dismutase（SOD）,malondialdehyde（MDA）enzyme-linked immunosorbent assay kit and nonesterified fatty acids（NEFA）colorimetric assay kit were used to evaluate the antioxidant capacity of larval zebrafish.RT-qPCR was used to detect the expression of mRNA related to lipid metabolism,inflammation and oxidative stress in larval zebrafish.Results:The results showed that TSG reduced the mortality,body weight and body length of larval zebrafish with NAFLD,and reduced the lipid deposition in the liver.What’s more,TSG also reduced the levels of TC,TG,ALT,AST,ROS,MDA,NEFA and enhanced the activity of HDL-c,SOD of larval zebrafish.The underlying mechanisms of the anti-NAFLD effects of TSG are related to suppress the expression of FASN,SREBF1,CPT1A,IKKβ,NF-κB,IL-6,IL-1β,TNF-αand Keap1 genes,and promote the expression of PPAR-α,PPAR-γ,Nrf2,HO-1 genes.Furthermore,IKKβ/NF-κB and Keap1-Nrf2 pathways could be the potential targets of TSG to play anti-inflammatory and antioxidant roles.Conclusion:TSG has good improving effects on larval zebrafish with NAFLD induced by 5%high-cholesterol diet,whose mechanisms involve the regulation of lipid metabolism-related pathway,anti-inflammatory pathway IKKβ/NF-κB and antioxidant pathway keap1-Nrf2.