Protective Effect of Recombinant Interferon (IFN)-α/β on MHV-2cc-induced Chronic Hepatitis in Athymic Nude Mice

Abstract

The protective effects of recombinant IFN-α/β on MHV-2cc-induced chronic and persistent hepatitis in athymic nude mice were examined. The mice intraperitoneally (ip) inoculated with MHV-2cc at day 0 of experiment were divided into 4 groups. Three of them were administered ip with recombinant IFN-α/β at a daily dose of 1 × 103 IU from -1 (-1D-group), 0 (0D-group), and +1 day of experiment (+1D-group), respectively, for 3 consecutive weeks. The remaining one (control group) was given 0.1 ml/mouse of PBS from +1 day of the experiment in the same way. Three mice in each group were killed at 1, 2 and 3 weeks post inoculation (WPI) with MHV, respectively. The liver virus titer in the control group increased gradually and maintained high levels throughout the experimental period. In the IFN-groups, particularly in the -1D- and 0D-groups, the virus titers were significantly lower than that in control group. Histopathologically, focal hepatic lesions were observed at 1WPI and large irregular inflammatory lesions developed at 3WPI in the control group. Similar but somewhat less severe lesions were observed in the +1D-group. In the -1D- and 0D-groups, lesions were not observed at 1WPI and only small organized lesions with mononuclear cell infiltration were seen at 3WPI. In conclusion, it was clarified in the present study that the progression of MHV-2cc-induced chronic hepatitis in athymic nude mice was effectively prevented by extrinsic IFN-α/β when administered from -1 day and 0 day of the virus infection.