OBJECTIVETo establish and identify an animal model of non-alcoholic fatty liver disease in chronic HBV infected mice.

METHODSTransgenic mice with sustaining HBV production were established by microinjection of ocyte. Then they were randomly assigned into 4 groups (male control, male NAFLD model, female control and female NAFLD model) and treated with high fat diet (2% cholesterol, 10% lard, 88% forage) and common forage, respectively. NAFLD-related physical indexes, liver and kidney function, glucose and lipid metabolism were investigated at the time points of 8 weeks, 16 weeks and 24 weeks. Meanwhile, HBV type, serum levels of HBV DNA and HBeAg, immunohistochemical staining of hepatic HBsAg were detected. The establishment of NAFLD was evaluated by serum levels of total cholesterol (TC), triglycerides, glucose, aspartate aminotransferase (AST), alkaline phosphatase (ALP), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), etc. Histological changes were also analyzed by HE, oil red O and Masson's trichrome staining. The status of CHB was assessed on the basis of immunohistochemistry and real-time PCR.

RESULTSThe body and liver weights, liver index in HBV transgenic mice were significantly increased in regardless of the gender of HFD feeding, and the levels of serum ALT, AST, ALP, GGT, TBIL, TBA, TC, TG, HDL-C, LDL and FBG were higher in HFD groups as compared with the control mice. Lipid droplets, cytologic ballooning and liver steatosis could be observed in most lobules of HFD groups after 8-week administration, fatty degeneration of hepatocytes, patch necrosis, mild to moderate chronic inflammatory infiltration were also observed in some of HFD feeding, reflecting the emerge of steatohepatitis. At the time point of 24-week perisinusoidal fibrosis and local fibrosis occurred in HFD groups. Immunohistochemical staining and real-time PCR analysis of the liver tissues showed positive signal of HBsAg in all groups of mice, although no significant difference was documented.

CONCLUSIONOur study suggests that animal model of NAFLD can be established in HBV transgenic mice and provide a nice animal model for further studies on NAFLD with chronic hepatitis B infection.