The effects of hydrogen treatment in a cigarette smoke solution-induced chronic obstructive pulmonary disease-like changes in an animal model.
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
Abstract
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.
Mechanism
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.
Bibliographic
- Authors
- Yang H, Tsou WH, Shen M, Liu C, Saunders HM, Wang K, et al.
- Journal
- J Thorac Dis
- Year
- 2022
- PMID
- 36524091
- DOI
- 10.21037/jtd-22-324
- PMC
- PMC9745525
Tags
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.
Safety notes
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