Therapeutical Effects And Mechanisms Of Polydatin On Alcoholic Fatty Liver In Zebrafish Larvae

Background:Alcohol abuse is deemed to be the principle cause of Alcoholic liver disease(ALD),one of the most common form of liver diseases which encompasses a spectrum of disorders and pathologic changes in liver tissue,ranging from simple steatosis,steatohepatitis,to fibrosis and cirrhosis.Hepatic steatosis induced by alcohol abuse is the early stage of ALD,and may progress to more severe forms of ALD.Polydatin(3,4,5-trihydroxystibene-3-?-mono-d-glucoside),as the primary active component of Polygonum cuspidatum,is being investigated in terms of hepatoprotective and neuroprotective efficacy for its potent antioxidant and anti-inflammatory properties.Studies manifest that polydatin presents biological characteristics of anti-lipid peroxidation,anti-inflammation,hypolipidemia,vascular protection,anti-thrombosis,anti-shock,improvement of microcirculation.However,the functions and molecular mechanisms of polydatin that protects against acute alcoholic liver injury requires in-depth research.As far as we know,it is the first study to explore the efficacy that polydatin works on ethanol-induced ALD in zebrafish larvae.Compared to traditional animal models,zebrafish larvae possess the characteristics of high efficiency,huge sample size,strong repeatability,optical clarity and easy observation.It is of obvious superiority in establishing acute alcoholic fatty liver model and screening drugs.Purpose:To investigate whether polydatin alleviates ethanol induced liver injury and to elucidate the underlying molecular mechanisms,we carried out this study on zebrafish larvae.Experimental Animals and Methods:1.Animals:Zebrafish from Wild type AB strain and Tg(lfabpl0?:e GFP)transgenics.2.Methods:Zebrafish larvae at 4 days post-fertilization(dpf)were exposed to 2%of ethanol for 32 h.After ethanol exposure,the larvae were randomly divided into 6 groups:normal control group,model group(treated with fish water),DMSO group and 3 polydatin intervention groups.Results of H&E,Oil red O,Nile Red staining and phenotype of zebrafish larvae were observed to assess the model.The mRNA levels which are related to alcoholic fatty liver were measured by quantitative PCR and the antioxidant property was detected using ROS fluorescent probe.Results:H&E,Oil Red O,and Nile Red staining revealed that lipid vacuolation diminished after polydatin treatment,especially under a concentration of 0.064mol/L.Our study demonstrated that fluorescent probe could be applied to detect ethanol-induced ROS on zebrafish larvae and polydatin could prevent the liver from being injured by oxidative stress.Besides,polydatin strongly alleviated hepatic steatosis and decreased the expression levels of alcohol and lipid metabolism-related genes,including CYP2Y3,CYP3A65,HMGCRa,HMGCRb and FASN.Additionally,significantly up-regulated expression of DNA damage-related genes(CHOP,GADD45aa)revealed that polydatin attenuated hepatic apoptosis in larvae.Conclusion:In conclusion,polydatin may improve the liver function of zebrafish with acute alcoholic liver injury through attenuating hepatic fat accumulation,ameliorating lipid and ethanol metabolism and reducing oxidative stress and DNA damage.