Pharyngeal aspiration of metal oxide nanoparticles showed potential of allergy aggravation effect to inhaled ovalbumin

Abstract

The inhalation of manufactured metal oxide nanoparticles may lead to pulmonary toxicity. For instance, ZnO nanoparticles are known to induce pulmonary oxidative stress and inflammation. On the other hand, the pulmonary toxicity of TiO₂ nanoparticles is less than that of ZnO nanoparticles. Although, there have been some investigations concerning the induction of pulmonary oxidative stress and inflammation caused by manufactured metal oxide nanoparticles. And, although, it has reported that some nanoparticles cause aggravation of allergic reactions, there have so far been no reports regarding allergy aggravation effects of manufactured metal oxide nanoparticles. In this study, three types of nanoparticles, TiO₂, ZnO and SiO₂, were administered to mouse lungs by pharyngeal aspiration. Subsequently, the mice inhaled ovalbumin (OVA) a total of eight times over 3 weeks. After inhalation of OVA, the concentrations of total IgE, OVA-specific IgE and OVA-specific IgG₁ in serum increased in the mice treated with ZnO. TiO₂ and SiO₂ nanoparticles did not affect the OVA-specific IgE and IgG₁ levels. These results suggest that ZnO nanoparticles have the potential to aggravate allergic reactions. The results also suggest that Zn²⁺ release from ZnO nanoparticles is involved in the aggravation potential of allergies. However, pharyngeal aspiration of ZnCl₂ solution was not able to aggravate allergic reactions. Continuous Zn²⁺ release from ZnO nanoparticles to the lung is necessary for the aggravation of allergic reactions.

• Allergy aggravation
• nanoparticle
• ovalbumin
• zinc oxide

Declaration of interest

This work was funded by JSPS KAKENHI Grant Number 25871005. The authors report no declarations of interest.