Beneficial effects of hydrogen gas inhalation on a murine model of allergic rhinitis.

Allergic rhinitis (AR) is a common chronic inflammatory condition. It has been previously indicated that oxidative stress may contribute to allergic inflammation, including AR. Although molecular hydrogen (H), an antioxidative agent, has been effective in treatment of numerous oxidative stress-associated diseases, the effect of inhalation of a high concentration of H on AR remains unknown. In the current study, female BALB/c mice were sensitized with ovalbumin (OVA) followed by intranasal OVA challenge to establish an animal model of AR. Mice were subjected to exposure to H and the inert gas helium at different frequencies and durations. The frequencies of sneezing/scratching and the body weights of mice were recorded. Histological analysis and multiplex cytokine assays were performed to evaluate the effects of H on AR. Challenge with OVA induced significant nasal mucosa inflammation. H inhalation reduced the infiltration of inflammatory cells into mucosa and lowered the levels of interleukin (IL)-5, IL-13 and monocyte chemoattractant protein-1 in serum. H inhalation slightly increased the level of interferon-γ, however the difference was not statistically significant. Treatment with H limited the weight increase in healthy mice and reversed the weight loss in mice with AR. Furthermore, H inhalation induced a therapeutic effect on AR in a dose-dependent manner. The current results demonstrate that H may demonstrate a therapeutic value for allergic diseases.