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

アレルギー性鼻炎マウスモデルにおける水素ガス吸入の有益な効果

animal study inhalation positive

Abstract

Allergic rhinitis (AR) is a chronic inflammatory condition in which oxidative stress is thought to play a contributing role. Using an ovalbumin (OVA) sensitization and intranasal challenge protocol in female BALB/c mice, this study examined the effects of high-concentration H2 gas inhalation at varying frequencies and durations. OVA challenge produced marked nasal mucosal inflammation. H2 inhalation reduced inflammatory cell infiltration into the nasal mucosa and decreased serum concentrations of IL-5, IL-13, and monocyte chemoattractant protein-1. Interferon-γ showed a slight, non-significant increase. Body weight loss observed in AR mice was reversed by H2 exposure, while weight gain in healthy mice was modestly limited. The protective effects were dose-dependent, suggesting that H2 inhalation may have value in managing allergic airway inflammation.

Mechanism

H2 inhalation suppressed Th2-associated cytokines (IL-5, IL-13) and MCP-1 in serum, reducing inflammatory cell infiltration into nasal mucosa, likely through its antioxidative properties that attenuate oxidative stress-driven allergic inflammation.

Bibliographic

Authors
Fang S, Li XM, Wei X, Zhang YJ, Ma Z, Wei Y, et al.
Journal
Exp Ther Med
Year
2018
PMID
30542474
DOI
10.3892/etm.2018.6880
PMC
PMC6257674

Tags

Delivery:inhalation delivery (196) Mechanism:immune modulation (180) anti-inflammatory (743) oxidative stress (899) reactive oxygen species (774)

Delivery context

In air, molecular hydrogen is reported to be combustible across approximately **4% (LFL, lower flammability limit) to 75% (UFL, upper flammability limit)**. Among high-concentration hydrogen inhalers, 66% output sits inside this range, and even pure-hydrogen (100%) output forms a 4–75% concentration-gradient layer at the device–air boundary (the UFL 75% paradox). Engineering principle would therefore call for operation below LFL (the classical 4%); that figure, however, was measured under closed, pre-mixed, static conditions. For the open, dynamic inhalation environment, the empirical value reported in the literature is **10%**, which is the figure referenced in practice as the operating ceiling. The 66% / 100% output devices are recorded in the Japanese Consumer Affairs Agency accident-information database, and from these considerations are not recommended.

→ Evidence by delivery route

Safety notes

In air, molecular hydrogen is reported to be combustible across approximately **4% (LFL, lower flammability limit) to 75% (UFL, upper flammability limit)**. Among high-concentration hydrogen inhalers, 66% output sits inside this range, and even pure-hydrogen (100%) output forms a 4–75% concentration-gradient layer at the device–air boundary (the UFL 75% paradox). Engineering principle would therefore call for operation below LFL (the classical 4%); that figure, however, was measured under closed, pre-mixed, static conditions. For the open, dynamic inhalation environment, the empirical value reported in the literature is **10%**, which is the figure referenced in practice as the operating ceiling. The 66% / 100% output devices are recorded in the Japanese Consumer Affairs Agency accident-information database, and from these considerations are not recommended.

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