分子状水素の抗炎症作用：寄生虫誘発性肝炎症モデルにおける検討
Molecular hydrogen reacts with hydroxyl radicals, which are highly cytotoxic species generated in inflamed tissues. Using a schistosomiasis-associated chronic liver inflammation model in animals, this study examined the effects of hyperbaric hydrogen exposure (0.7 MPa supplemented to normal atmosphere) over a 2-week period. Infected animals showed significant hepatoprotective outcomes, including reduced fibrosis, improved hemodynamics, elevated NOSII and antioxidant enzyme activities, lower lipid peroxide levels, and decreased circulating TNF-alpha concentrations. Notably, helium under identical conditions also conferred partial protection, suggesting that hydroxyl radical scavenging alone does not account for all observed benefits. These results indicate that additional protective mechanisms beyond radical quenching may be involved in hydrogen-mediated anti-inflammatory effects.
Hydrogen scavenges hydroxyl radicals in inflamed tissue and additionally upregulates NOSII activity and antioxidant enzymes while suppressing TNF-alpha. The partial protective effect of helium under identical conditions suggests that radical scavenging is not the sole mechanism involved.
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/11510417