Abstract:

Objective To detect changes in TLR-4 and IL-6 in tree shrews infected by hepatitis B virus. Methods A total of 25 tree shrews were inoculated with human hepatitis B virus （HBV） and then divided into an HBV-infected group，suspected HBV-infected group and control group based on detection of the HBV marker HBsAg or HBV DNA using a photochemical method or fluorescence- probe PCR. HBV-infected animals showed persistent positive results for HBsAg or HBV DNA，while the suspected HBV-infected group showed two or more positive results for HBsAg or HBV DNA. Levels of TLR-4 and IL-6 in peripheral blood and liver tissues were measured using，respectively，enzyme-linked immunosorbent assay （ELISA） and hematoxylin- eosin staining. Levels of TLR-4 and IL-6 mRNA in liver tissue of all three groups were measured using real-time fluorescence quantitative PCR. All assays were performed between post-natal weeks 8 and 24. Results Seven animals were assigned to the HBV-infected group，while five were assigned to the suspected HBV-infected group； all control animals showed negative results. Levels of TLR-4 in the peripheral blood of infected and suspected infected animals were significantly higher than in control animals （P＜0.05）at weeks of 8，12，16，20，and 24. Levels were not significantly different between the infected and suspected infected groups. Similar results were observed for levels of IL-6 in peripheral blood. Levels of TLR-4 and IL-6 mRNA in liver tissue were significantly higher in the infected and suspected infected groups than in the control group（P＜0.05）. Conclusion Levels of TLR-4 and IL-6 are elevated in tree shrews following infection with HBV virus，and these signaling molecules may play an important role in the infection process.

Key words: Hepatitis B virus, TLR-4, IL-6, Tree shrew, Immune response