Inhalation of 4% and 67% hydrogen ameliorates oxidative stress, inflammation, apoptosis, and necroptosis in a rat model of glycerol-induced acute kidney injury.
グリセロール誘発急性腎障害ラットモデルにおける4%および67%水素吸入による酸化ストレス・炎症・アポトーシス・ネクロプトーシスの改善
Abstract
Using a rat model of rhabdomyolysis-associated acute kidney injury (AKI) induced by glycerol injection (8 mL/kg), this study evaluated the renoprotective effects of inhaled molecular hydrogen at two concentrations (4% and 67%) over 72 hours. Glycerol administration triggered oxidative stress, inflammatory responses, apoptosis, and necroptosis, accompanied by decreased antioxidant enzyme activity and elevated kidney injury biomarkers. H2 inhalation reversed these pathological changes and conferred renal protection. Although a consistent dose-response relationship was not observed across all AKI-related parameters, the higher concentration (67%) produced superior improvements in histological and morphological outcomes. The findings indicate that H2 inhalation may reduce rhabdomyolysis-induced renal damage through antioxidant, anti-inflammatory, anti-apoptotic, and anti-necroptotic mechanisms.
Mechanism
H2 inhalation is proposed to preserve antioxidant enzyme activity while suppressing inflammatory signaling, apoptotic pathways, and necroptosis, collectively reducing renal cell damage in glycerol-induced AKI.
Bibliographic
- Authors
- Xue J, Liu B, Zhao M, Zhang MH, Wang M, Gu QQ, et al.
- Journal
- Med Gas Res
- Year
- 2023
- PMID
- 36204787
- DOI
- 10.4103/2045-9912.345169
- PMC
- PMC9555022
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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