タバコ煙溶液誘発COPDモデルマウスにおける水素吸入の肺組織学的効果
Using female BALB/c mice with COPD-like lung injury induced by intraperitoneal injection of cigarette smoke solution (CSS) twice weekly for 6 weeks, this study examined the effects of inhaling a 42% hydrogen-oxygen gas mixture for 75 minutes twice daily over 9 weeks. Compared with untreated COPD mice, the hydrogen-exposed group showed a higher survival rate (100% vs 80%) during the induction phase. Histopathological assessment revealed significant improvements in mean linear intercept (MLI) and composite lesion scores encompassing inflammation and emphysema. Neutrophil elastase activity was numerically reduced in hydrogen-treated animals, although the difference did not reach statistical significance. Goblet cell hypertrophy and airway epithelial hyperplasia did not show significant improvement. These findings suggest that hydrogen-oxygen inhalation can partially ameliorate alveolar structural damage and inflammatory pathology in a CSS-based COPD animal model.
Hydrogen's antioxidant and anti-inflammatory properties are thought to suppress neutrophil elastase activity, thereby reducing alveolar structural destruction and attenuating inflammatory lesion scores in CSS-exposed lung tissue.
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:
https://h2-papers.org/en/papers/36524091