Abstract
BACKGROUND: New approaches are urgently needed to fight influenza viral infection. Previous research has shown that zirconia nanoparticles can be used as anticancer materials, but their antiviral activity has not been reported. Here, we investigated the antiviral effect of zirconia (ZrO(2)) nanoparticles (NPs) against a highly pathogenic avian influenza virus. MATERIALS AND METHODS: In this study, the antiviral effects of ZrO(2) on H5N1 virus were assessed in vivo, and the molecular mechanism responsible for this protection was investigated. RESULTS: Mice treated with 200 nm positively-charged NPs at a dose of 100 mg/kg showed higher survival rates and smaller reductions in weight. 200 nm ZrO(2) activated mature dendritic cells and initially promoted the expression of cytokines associated with the antiviral response and innate immunity. In the lungs of H5N1-infected mice, ZrO(2) treatment led to less pathological lung injury, significant reduction in influenza A virus replication, and overexpression of pro-inflammatory cytokines. CONCLUSION: This antiviral study using zirconia NPs shows protection of mice against highly pathogenic avian influenza virus and suggests strong application potential for this method, introducing a new tool against a wide range of microbial infections.