Abstract: BACKGROUND ＆ AIM: To explore the feasibility of hepatitis B virus (HBV) vertical transmission via male germ line, the replication and expression of sperm-mediated HBV DNA in mouse embryo were studied. MATERIAL AND METHODS: Young adult male mice were injected with HBV DNA-liposome complex. These males were serially mated with superovulated females 2 days after injection. Fluorescence in situ hybridization (FISH) was carried out to confirm the integration of HBV DNA into male pronucleus and its replication with cell division in embryonic development.(Reverse transcriptase polymerase chain reaction,RT-PCR) and immunofluoresence assay were performed to observe the expression of the HBV gene in two-cell stage. RESULTS: FISH demonstrated that the male pronuclei in some one-cell embryos and the each nucleus in some two-cell embryos presented positive signals. RT-PCR showed the specific bands of cDNA of HBx DNA in some two-cell embryos. Immunofluorescence assay presented the positive signals for HBsAg in some two-cell embryos. CONCLUSION: Our results provided the direct evidence for that HBV DNA are able to transmit vertically to next generation via male germ line.

Key words: hepatitis B virus DNA, replication and expression, early embryo, vertical transmission