title: High fat plus high cholesterol diet lead to hepatic steatosis in zebrafish larvae: a novel model for screening anti-hepatic steatosis drugs.
abstract: BACKGROUND
  Non-alcoholic fatty liver disease (NAFLD), characterized as excessive lipid accumulation within hepatocytes, is growing in prevalence. The exploitation of effective drugs for NAFLD has been proven challenging. Herein, we aimed to establish a dietary model of hepatic steatosis using transparent zebrafish larvae in which high-throughput chemical screens could be conducted.
  
  
  METHODS
  Zebrafish larvae fed with high fat (HF) diet and high fat plus high cholesterol (HFC) diet were compared to the control. We analyzed intrahepatic lipid accumulation, biological indexes and various pathways including lipid metabolism, ER stress and inflammation. In addition, the effects of ezetimibe and simvastatin on HFC diet-induced steatosis were evaluated.
  
  
  RESULTS
  Zebrafish larvae fed with HF and HFC diets developed steatosis for 7 and 10 days. The incidence and degree of steatosis were more severe in HFC diet-fed larvae compared with the control and HF diet-fed larvae, suggesting that adding cholesterol to the HF diet promotes the hepatic lipid accumulation. These data were confirmed by the pathological observation. Biological indexes, free cholesterol (FC), total cholesterol (TC) and triacylglycerol (TG) were elevated in the liver of HFC diet-fed larvae compared with the control and HF diet-fed larvae. Additionally, the expression levels of endoplasmic reticulum (ER) stress and lipolytic molecules (atf6, hspa5, hsp90b1, pparab, cpt1a and acox3) were significantly up-regulated in the liver of HF and HFC diets-fed larvae compared to the control, whereas the expression of lipogenic molecules (acaca, fasn, srebf2, hmgcs1 and hmgcra) were decreased in the liver of HF and HFC diets-fed larvae compared to the control. To validate the reliability of the HFC model and utility value for screening potential anti-steaotsis drugs, HFC-fed larvae were treated with two accepted lipid-lowing drugs (ezetimibe and simvastatin). The results showed that these drugs significantly ameliorated HFC-induced steatosis.
  
  
  CONCLUSIONS
  Our results demonstrate that the zebrafish larvae steatosis model established and validated in this study could be used for in vivo steatosis studies and drug screening.
authors.affiliation: State Key Laboratory of Organ Failure Research, Guangdong Provincial Key, Laboratory of Viral Hepatitis Research, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 China.
authors.forename: Wencong
authors.initials: W
authors.lastname: Dai
authors.affiliation: State Key Laboratory of Organ Failure Research, Guangdong Provincial Key, Laboratory of Viral Hepatitis Research, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 China.
authors.forename: Kunyuan
authors.initials: K
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Organ Failure Research, Guangdong Provincial Key, Laboratory of Viral Hepatitis Research, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 China.
authors.forename: Xinchun
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Zebrafish Modeling and Drug Screening for Human Diseases of Guangdong Higher Education Institutes, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Chen
authors.affiliation: Key Laboratory of Zebrafish Modeling and Drug Screening for Human Diseases of Guangdong Higher Education Institutes, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 China.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Zebrafish Modeling and Drug Screening for Human Diseases of Guangdong Higher Education Institutes, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 China.
authors.forename: Yiyue
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Organ Failure Research, Guangdong Provincial Key, Laboratory of Viral Hepatitis Research, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 China.
authors.forename: Jinlin
authors.initials: J
authors.lastname: Hou
authors.affiliation: State Key Laboratory of Organ Failure Research, Guangdong Provincial Key, Laboratory of Viral Hepatitis Research, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
keywords: Drug screening; Hepatic steatosis; Lipid accumulation; Zebrafish