High fat plus high cholesterol diet lead to hepatic steatosis in zebrafish larvae: a novel model for screening anti-hepatic steatosis drugs

Abstract

BackgroundNon-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.MethodsZebrafish 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.ResultsZebrafish 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.ConclusionOur 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12986-015-0036-z) contains supplementary material, which is available to authorized users.

Palmitic Acid-Enriched Diet Induces Hepatic Steatosis and Injury in Adult Zebrafish

“…The zebrafish is an excellent model system for studying liver diseases because of the organ system homology to humans including cell types and gene expressions. 6,7 Zebrafish larvae have been used to study alcoholic and nonalcoholic fatty liver disease 6,[8][9][10] ; however, results from larvae may not represent chronic liver disease in adults. Adult zebrafish have not been used as a model for fatty liver disease, but recent articles reported fatty liver development after chronic alcohol exposure or trans-fat diet in adult zebrafish.…”

Triclocarban at environmentally relevant concentrations induces the endoplasmic reticulum stress in zebrafish

“…ER stress, which is known to incur steatosis, leads to disorder of lipid metabolism and induces lipid droplet deposition in zebrafish liver . Here, we observed that the expression levels of atf4 and chop were elevated in the zebrafish liver exposed to TCC compared with those in the control, indicating that TCC leads to ER dysfunction.…”

Possible association of arrestin domain-containing protein 3 and progression of non-alcoholic fatty liver disease

“…Heat shock protein 90 kDa alpha (cytosolic), class A member 1 (HSP90AA1) was the only gene that was significantly upregulated. Expression levels of endoplasmic reticulum molecule Heat shock protein 90 kDa beta (Grp94), member 1 (HSP90B1) were significantly up-regulated in the livers of zebrafish larvae fed high fat with or without high cholesterol diets [27]. Baculoviral IAP repeat containing 3 (BIRC3), a severe hypoxia-activated gene, was significantly increased in simple hepatic steatosis compared with the controls [28].…”