# Evaluation of the therapeutic effects of nebulized inhalation of hydrogen-rich water on primary blast lung injury in C57BL/6 mice.
> 水素富化水ネブライザー吸入による一次爆風肺損傷に対する効果：C57BL/6マウスを用いた検討


## Abstract

This animal study investigated the effects of nebulized hydrogen-rich water on primary blast lung injury in C57BL/6 mice. A total of 150 mice (aged 6–8 weeks) were randomly assigned to a hydrogen-rich water nebulization group or a control group (n=75 each) and subjected to blast overpressure of 266±9.156 kPa. Assessments at 6, 12, 24, and 48 hours post-injury showed that the hydrogen-rich water group had significantly higher survival rates (81.3% vs 61.3% at 24 hours, P<0.01). Pulmonary function improved, with greater tidal volume, normalized respiratory rate, and higher minute ventilation. Arterial blood gas analysis demonstrated enhanced oxygenation and reduced hypercapnia. Histological findings indicated less pulmonary edema and hemorrhage. Inflammatory cytokines (IL-1β, IL-6, TNF-α) and the oxidative stress marker malondialdehyde were significantly reduced, while total superoxide dismutase activity was elevated in the hydrogen-rich water group compared with controls (P<0.01).

### Mechanism

Hydrogen's antioxidant properties suppress malondialdehyde production and enhance superoxide dismutase activity, while its anti-inflammatory action reduces IL-1β, IL-6, and TNF-α levels, collectively limiting alveolar and capillary damage following blast overpressure exposure.

## Bibliographic

- **Authors**: Qu Y, Chen Q, Chai J, Hu F, Liu TT, Liu X, et al.
- **Journal**: Surgery
- **Year**: 2025
- **PMID**: [39799761](https://pubmed.ncbi.nlm.nih.gov/39799761/)
- **DOI**: [10.1016/j.surg.2024.109044](https://doi.org/10.1016/j.surg.2024.109044)
- **Study type**: animal study
- **Delivery route**: inhalation
- **Effect reported**: positive

## Delivery context

For inhalation applications of molecular hydrogen, the lower flammability limit (LFL) deserves careful handling. The classical 4% figure applies to closed-system mixtures; the practical inhalation-environment threshold is 10%. Even pure-hydrogen output (the UFL 75% paradox) passes through the flammable range at the air–gas boundary. High-concentration (66% / 100%) inhalers are documented in the Japanese Consumer Affairs Agency accident-information database and are not recommended.

## Safety notes

For inhalation applications of molecular hydrogen, the lower flammability limit (LFL) deserves careful handling. The classical 4% figure applies to closed-system mixtures; the practical inhalation-environment threshold is 10%. Even pure-hydrogen output (the UFL 75% paradox) passes through the flammable range at the air–gas boundary. High-concentration (66% / 100%) inhalers are documented in the Japanese Consumer Affairs Agency accident-information database and are not recommended.

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [LFL / UFL terminology](https://h2-papers.org/en/safety-notes/lfl-ufl-explained)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 39799761. https://h2-papers.org/en/papers/39799761
> **Source**: PubMed PMID [39799761](https://pubmed.ncbi.nlm.nih.gov/39799761/)