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Beneficial effects of hydrogen gas against spinal cord ischemia-reperfusion injury in rabbits.

ウサギ脊髄虚血再灌流障害に対する水素ガス吸入の保護効果

animal study inhalation positive 1–4%

Abstract

A rabbit model of spinal cord ischemia was established by occluding the infrarenal aorta for 20 minutes in male New Zealand white rabbits. Hydrogen gas at concentrations of 1%, 2%, or 4% was administered by inhalation beginning 10 minutes before reperfusion and continuing for 60 minutes afterward (70 minutes total). Animals receiving 2% or 4% H2 showed significant preservation of normal motor neuron counts and improved hindlimb motor function compared with untreated controls. Biochemical analyses of serum and spinal cord tissue revealed reductions in oxidative stress markers (8-iso-PGF2α and MDA) and pro-inflammatory cytokines (TNF-α and HMGB1), alongside elevated activities of antioxidant enzymes (SOD and catalase). Motor neuron apoptosis in the spinal cord was also markedly reduced in H2-treated animals, suggesting that hydrogen inhalation engages antioxidant and anti-inflammatory pathways to confer neuroprotection following spinal cord ischemia-reperfusion.

Mechanism

H2 inhalation reduces lipid peroxidation products (8-iso-PGF2α, MDA) and pro-inflammatory cytokines (TNF-α, HMGB1) while enhancing SOD and catalase activities, thereby suppressing oxidative damage and motor neuron apoptosis in ischemia-reperfusion-injured spinal cord tissue.

Bibliographic

Authors
Huang Y, Xie K, Li J, Xu N, Gong G, Wang G, et al.
Journal
Brain Res
Year
2011 (2011-03-10)
PMID
21195696
DOI
10.1016/j.brainres.2010.12.071

Tags

Disease:ischemia-reperfusion injury (107) spinal cord injury (13) Delivery:inhalation delivery (196) Mechanism:antioxidant enzymes (423) apoptosis regulation (280) anti-inflammatory (743) lipid peroxidation (238) oxidative stress (899)

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:

Other papers on the same disease / condition