Hydrogen Inhalation Reduces Lung Inflammation and Blood Pressure in the Experimental Model of Pulmonary Hypertension in Rats.
モノクロタリン誘発肺高血圧症ラットモデルにおける水素吸入の肺炎症および血圧への影響
Abstract
Using a monocrotaline-induced pulmonary hypertension model in male Wistar rats, this study examined the effects of continuous inhalation of atmospheric air containing 4% molecular hydrogen over 21 days. Monocrotaline was administered subcutaneously on day 1, and hemodynamic parameters were assessed under urethane anesthesia at day 21. Although hydrogen inhalation did not significantly alter the primary markers of pulmonary hypertension, systolic blood pressure was reduced in the hydrogen-exposed group. Additionally, TGF-β expression was decreased and the number of tryptase-containing mast cells in lung tissue was diminished. These findings suggest that hydrogen gas exerts partial anti-inflammatory and antioxidant effects in this oxidative stress-driven model, influencing systemic hemodynamics and inflammatory cell populations without fully reversing pulmonary vascular remodeling.
Mechanism
Molecular hydrogen selectively scavenges hydroxyl radicals, reducing oxidative stress induced by monocrotaline. This antioxidant action is associated with decreased TGF-β expression and a reduction in tryptase-positive mast cells, contributing to partial attenuation of lung inflammation and lowering of systolic blood pressure.
Bibliographic
- Authors
- Kuropatkina T, Atiakshin D, Sychev F, Artemieva M, Samoilenko T, Gerasimova O, et al.
- Journal
- Biomedicines
- Year
- 2023 (2023-11-25)
- PMID
- 38137362
- DOI
- 10.3390/biomedicines11123141
- PMC
- PMC10740706
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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