| Objective:Till now, the precise mechanism of HBV clearance remains unclear. It is known that Interferon (IFN) production during the early stage of virus infection plays the important role in virus clearance, and Interferon regulation factor-7 (IRF-7) is one of the key factors in the process of IFN production. So in this study, a mouse model with acute HBV infection was used to observe the change in mRNA or protein expression of IFN-β or IRF-7 gene in mouse liver, to analyze the relationship between these changes and HBV infection, and to explore the effect of IFN-P or IRF-7 in the clearance mechanism of acute HBV infection.Methods:1. A mouse model of acute HBV infection was constructed by hydrodynamics-based injection with pcDNA3.1-HBV1.3 plasmid (pHBV group). The mice injected with empty vector pcDNA3.1 were set as control group (pcDNA group).2. Levels of HBsAg and HBeAg in mice serum were determined by electrochemiluminescence immunoassay (ECLIA).3. HBsAg or HBcAg expression in liver specimen was detected with immunohistochemical staining.4. The mRNA expression of IRF-7 or IFN-P in the liver specimen from NC group, pHBV group or pcDNA group at different time was measured with reverse transcriptive quantitative real time PCR (RT-QPCR).5. IFN-P protein expression in mouse liver was detected by ELISA.6. IRF-7 protein expression in mouse liver was measured by Western Blot.7. SPSS 20.0 software was used for variance analysis and correlation analysis.Results:1. Serum HBsAg was negative at 6 h after pHBV plasmid injection, positive at 24 h (113.89±31.06 COI) (>1 COI was positive), peaked at 48 h (303.40±74.105 COI) and declined gradually. While serum HBeAg was positive at 24 h after pHBV plasmid injection, then declined gradually. HBsAg or HBeAg showed negative in NC or pcDNA group.2. HBsAg or HBcAg expression was detected positive at 6h in liver specimen from pHBV mice. The highest rate of HBsAg or HBcAg-expressing hepatocytes was shown at 12h post-injection (20% or 18%), followed with a sharp decline. HBsAg or HBeAg expression showed negative in liver specimen from NC or pcDNA group.3. IFN-P gene expression (mRNA) in liver from pHBV group elevated at 6h (3.4-fold relative to NC groups), got the peak at 12h (66.5-fold relative to NC group) and decreased subsequently. There were significant differences at the 6h,12h or 24h between pHBV and pcDNA or NC group (P<0.05). IFN-β protein expression in pHBV group increased at 12h (8.7-fold relative to NC group) and was higher significantly than pcDNA or NC group (P<0.05). There showed no significant differences between NC and pcDNA group at each time point (P>0.05)4. IRF-7 gene expression (mRNA or protein) in liver specimen from pHBV group was significantly higher than pcDNA or NC group at 6h,12h or 24h (P<0.05). IRF-7 mRNA or protein expression of pHBV group got the peak at 12h (5.3-fold or 4.4-fold relative to NC group), then declined gradually, and finally showed no significant difference at 48h compared with pcDNA or NC group (P>0.05). No significant difference between pcDNA group and NC group was found at each time point (P>0.05)5. IFN-β mRNA expression was correlated with the rate of HBsAg or HBcAg positive hepatocyte (p=0.01 or p=0.02), IRF-7 mRNA expression was correlated with the rate of HBsAg or HBcAg positive hepatocyte (p< 0.001), and IFN-β mRNA expression was correlated with IRF-7 mRNA expression (p=0.004)。Conclusion:A mouse model with acute HBV infection was successfully constructed. Both mRNA and protein expression of IRF-7 and IFN-β in liver had similar temporal patterns of change in HBV antigens expression in this model. These results suggest that IFN-β and IRF-7 might be involved in the process of HBV clearance after acute infection. |
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