The role of inducible nitric oxide synthase in a murine acute hepatitis B virus (HBV) infection model induced by hydrodynamics-based in vivo transfection of HBV-DNA

Background/Aims: Inducible nitric oxide synthase (iNOS) is found to have antiviral activity. Its role is evaluated using a murine acute hepatitis B virus (HBV) infection model. Methods: pHBV3.6 plasmid containing HBV genome was injected into mice by hydrodynamics-based in vivo transfection. HBV antigenemia and serum HBV-DNA were detected by enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction, respectively. HBV replication in liver was analyzed by Northern and Southern blot. Intrahepatic leukocytes were isolated and analyzed with flow cytometry. Results: After hydrodynamics injection of pHBV3.6, HBV genome was synthesized in the liver and HBV-DNA, as well as hepatitis B surface antigen and hepatitis B e antigen were secreted into the blood. Anti-HBV antibody responses developed afterward. A murine acute HBV infection model was established with hydrodynamics injection of non-transponase based HBV-DNA. Using this protocol in iNOS deficient or wild type B6 mice, the level of HBV transcript, replicative intermediate, and antigenemia were higher in iNOS-/- than in B6 mice. The intrahepatic leukocytes in iNOS -/- mice were also affected after transfection. Conclusions: Our data suggests that the iNOS expression not only affects the HBV clearance, but also modulates the infiltrating leukocytes response to HBV antigens.