H₂ Papers

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Molecular Hydrogen Prevents Social Deficits and Depression-Like Behaviors Induced by Low-Intensity Blast in Mice.

低強度爆風による社会行動障害およびうつ様行動に対する水素分子の予防効果（マウスモデル）

animal study inhalation positive

Abstract

Blast waves from explosive detonations can cause brain injury even without visible external trauma. Blast-induced mild traumatic brain injury (bmTBI) is increasingly prevalent in military personnel and is associated with blood-brain barrier disruption, oxidative stress, cerebral edema, psychiatric morbidity, and cognitive impairment. Using a laboratory-scale shock tube apparatus in mice, this study examined whether molecular hydrogen gas inhalation could mitigate bmTBI-related behavioral outcomes. Animals exposed to low-intensity blast and subsequently administered hydrogen gas showed significant reductions in social deficits and depression-like behaviors compared with untreated blast-exposed controls. These findings suggest that the antioxidant properties of molecular hydrogen may underlie its protective effects in this model of blast neurotrauma.

Mechanism

Molecular hydrogen is proposed to exert neuroprotective effects by scavenging reactive oxygen species generated after blast exposure, thereby reducing oxidative stress, blood-brain barrier disruption, and cerebral edema that underlie behavioral deficits in bmTBI.

Bibliographic

Authors
Satoh Y, Araki Y, Kashitani M, Nishii K, Kobayashi Y, Fujita M, et al.
Journal
J Neuropathol Exp Neurol
Year
2018 (2018-09-01)
PMID
30053086
DOI
10.1093/jnen/nly060

Tags

Disease:cognitive decline (111) depression / anxiety (34) Delivery:inhalation delivery (196) Mechanism:hydroxyl radical scavenging (352) anti-inflammatory (743) oxidative stress (899) reactive oxygen species (774)

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.

→ Evidence by delivery route

Safety notes

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.

See also:

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