The Effect And Mechanism Of DHA On Fructose Induced Hepatic Steatosis In Primary Mouse Hepatocytes

Objective: The increasing of dietary fructose intake can cause lipid accumulation in the liver, which may lead to hepatic steatosis. Some studies indicated that omega-3 PUFA(such as DHA) has been shown to be beneficial to the prevention for hepatic steatosis. In the present study, we explore the effects of DHA on hepatic lipid metabolism in fructose induced primary mouse hepatocytes and found possible mechanisms of DHA action.Methods: Primary mouse hepatocytes were prepared from male C57BL/6J mice referred to the hepatic portal vein perfusion method. The hepatocytes were treated with fructose, fructose and DHA, DHA,tunicamycin(TM) and 4-Phenylbutyric acid(PBA) and fructose for 24 hours. The lipid accumulation in primary mouse hepatocytes was assessed via Oil red O staining. The mRNA expression levels of lipid metabolism relating genes and endoplasmic reticulum stress were determined by q-PCR.The expression level of ACC、SREBP、ACOX1、GRP78/BIP、IRE and p-IRE were determined by Western blot.Results: The result of oil red o staining indicated that fructose and tunicamycin treatment led to an obvious lipid accumulation in primary mouse hepatocytes. DHA could ameliorate the lipid accumulation induced by fructose, and PBA pretreatment also could reduce lipid accumulation.Compared with control group, the FAS、ACC、SREBP 、GRP78 mRNA levels in fructose group and TM group were increased significantly. DHA and PBA could reduced the mRNA expression of increasing of FAS、ACC、SREBP and GRP78 induced by fructose. The expression of CPT1α and ACOX1 were elevated significantly in DHA group and fructose and DHA group. However, the mRNA expression levels of CPT1α and ACOX1 in PBA and fructose group were not significantly changed compared to fructose group. The results of Western blot shown that fructose and TM led to significantly elevated levels of ACC、SREBP 、GRP78/BIP、IRE and p-IRE protein, and the above four indicators were significantly reduced in fructose and DHA group or fructose and PBA group in comparison with fructose group. However, the protein level of ACOX1 were significantly increased in DHA group、fructose and DHA group and fructose and PBA group.Conclusion: Fructose intake may result hepatic steatosis, which is associated with ER stress induced by fructose to change the gene-ralated expression of hepatic lipid metabolism. DHA ameliorate hepatic lipid accumulation induced by fructose via regulating ER stress. The supplementof DHA in dietary can prevent the happening of NAFLD which induced by over-consumption fructose, thereby reducing the incidence of the disease.