Objective: To develop a mouse model of acute hepatitis B virus infection and to observe the RNA interference-mediated inhibition of HBV replication and expression in the mouse model.
Methods: Thirty Balb/c mice were randomly divided into 5 equal groups: group A to be injected with pHBV1.3, naked plasmid containing 1.3 time HBV ayw type whole genome eukaryotic expression vector, via the caudal vein as infection group; group B to be injected with pHBV1.3 and pSI-C, plasmid expressing HBV-C specific short hairpin RNA, as interference group; group C to be injected with pHBV1.3 and pSI-C mut, a mutant RNAi vector, as mutant interference group; group D to be injected with pHBV1.3 and pGFP, siRNA transcription vector targeting green fluorescence protein (GFP); and group E to be injected with PBS as blank controls. Six days after blood was collected and the mice were killed and their livers were taken out. ELISA was used to measure the concentration of HBsAg in the serum. Immunohistochemistry and RT-PCR were used to detect the expression of HBcAg and HBV C mRNA in the liver.
Results: Three days after injection the HBsAg expression in the sera of the infection group was strongly positive. Six days after injection expression of HBsAg was negative in the interference group and blank control group, and was positive in the infection group, mutant interference group, and irrelevant group, however, with significantly lower OD values in the latter 2 groups compared with in the infection group (both P < 0.05). Six days after injection immunohistochemistry showed that HBcAg expression in liver was positive in the infection group, weakly positive in the mutant interference group and irrelevant interference group, and was negative in the blank control group and interference group. RT-PCR showed clear expression of HBV C mRNA in the infection group, mutant interference group, and irrelevant interference.
Conclusion: RNAi technique specifically and effectively inhibits the replication and expression of HBV. siRNA has significant potential to become a new type antiviral drug. The establishment of an animal model of acute HBV infection in mice by hydrodynamic injection of naked plasmid has solved, to a certain degree, the problem of lack of appropriate animal model of HBV infection.