Pre-Treatment with Zirconia Nanoparticles Reduces Inflammation Induced by the Pathogenic H5N1 Influenza Virus

Huo, Caiyun; Xiao, Jin; Xiao, Kai; Zou, Shumei; Wang, Ming; Qi, Peng; Liu, Tianlong; Hu, Yanxin

In the present study, it seems paradoxical that 100 mg/kg ZrO 2 NPs is less effective for activation of DCs but appears to be more effective in protection when compared to lower doses. Previous researches by our team have researched the systemic toxicity of ZrO 2 NPs and demonstrated that dosages of ZrO 2 in the range of 100-350 mg/kg are safe for effectively clinical use. 33 However, we found that 100 mg/kg ZrO 2 NPs seemed to have a mild adverse reaction in H5N1-infected mice, which only showed the slightly low spirits just on day 1 after intraperitoneal administration. Thus, we consider that this clinical phenomenon may lead to the lower expression of immune indicators in spleen of the 100 mg/kg ZrO 2 group. Compared to 25 mg/kg ZrO 2 NPs or 50 mg/kg ZrO 2 NPs, 100 mg/kg ZrO 2 NPs group showed the most dramatic increases with time increasing, indicating its growing powerful immune responses. We suppose that 100 mg/kg ZrO 2 NPs group will show the better immune responses on day 7 or day 9 after intraperitoneal administration, which will be further investigated in future studies. Due to that NPs could be carried into the lung through the circulation, we speculate that 100 mg/kg ZrO 2 NPs can be carried into lung most effectively after viral infection when compared to 25 mg/kg ZrO2 NPs and 50 mg/kg ZrO 2 NPs, and then 100 mg/kg ZrO 2 NPs activate the antiviral responses in lung and eventually provide best protection for mice to fight against virus.