Protective effects of hydrogen gas against sepsis-induced acute lung injury via regulation of mitochondrial function and dynamics.
敗血症誘発性急性肺傷害に対する水素ガス吸入の保護効果：ミトコンドリア機能および動態の調節を介したメカニズム
Abstract
Using a cecal ligation and puncture (CLP) mouse model, this study examined the effects of 2% hydrogen gas inhalation on sepsis-induced acute lung injury (ALI) in male ICR mice divided into four groups: sham, sham plus H2, CLP, and CLP plus H2. At 24 hours post-operation, histological examination and transmission electron microscopy were performed. Compared with the CLP-only group, hydrogen gas inhalation significantly elevated the oxygenation index (PaO2/FiO2), mitochondrial membrane potential, ATP levels, respiration control ratio, complex I activity, and mitofusin-2 (MFN2) expression. Concurrently, histological injury scores and dynamin-related protein 1 (Drp1) levels were reduced. These findings indicate that 2% H2 inhalation can restore mitochondrial bioenergetics and shift the fission-fusion balance toward fusion, thereby conferring protection against sepsis-associated pulmonary damage.
Mechanism
H2 inhalation suppresses Drp1-mediated mitochondrial fission while upregulating MFN2-driven fusion, thereby restoring mitochondrial membrane potential, ATP synthesis, and respiratory complex I activity in septic lung tissue.
Bibliographic
- Authors
- Dong A, Wang Y, Li CY, Chen H, Bian Y, Zhang P, et al.
- Journal
- Int Immunopharmacol
- Year
- 2018
- PMID
- 30380511
- DOI
- 10.1016/j.intimp.2018.10.012
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
See also: