日本語 ・View as Markdown

Inhaled molecular hydrogen reduces hippocampal neuroinflammation, glial reactivity and ameliorates memory impairment during systemic inflammation.

吸入水素ガスによる全身性炎症時の海馬神経炎症・グリア反応性の抑制と記憶障害の改善

Abstract

Using a rat endotoxemia model induced by a single lipopolysaccharide (LPS) injection, this study examined how inhaled molecular hydrogen (H2) affects hippocampal neuroinflammation during systemic inflammation. Integrating approaches from hippocampal electrophysiology to behavioral testing, the investigators found that H2 inhalation reduced pro-inflammatory cytokine levels in both peripheral blood and hippocampal tissue. Microglial and astrocytic activation were also diminished. Behavioral assessments revealed attenuation of memory impairment, whereas long-term potentiation (LTP) remained unaffected. These findings represent the first reported evidence that inhaled H2 can suppress hippocampal microglial and astrocytic inflammatory responses, an effect associated with reduced cognitive deficits arising from systemic inflammation.

Mechanism

Inhaled H2 appears to reduce LPS-induced pro-inflammatory cytokine surges in the hippocampus by suppressing microglial and astrocytic activation, thereby limiting neuroinflammation and associated memory deficits without altering long-term potentiation.

Bibliographic

Authors

de Deus JL, Amorim MR, da Silva Junior RMP, Jesus AA, de Barcellos Filho PCG, Cárnio EC, et al.

Journal

Brain Behav Immun Health

Year

2023

PMID

37449286

DOI

10.1016/j.bbih.2023.100654

PMC

PMC10336161

Tags

Delivery context

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.

Safety notes

See also:

• Inhalation concentration and LFL / UFL
• Consumer Affairs Agency accident cases
• LFL / UFL terminology
• Inhalation safety threshold lineage

Other papers on the same disease / condition

• The protective effects of molecular hydrogen in sepsis-associated encephalopathy: current status.
  2026 ・ Eur J Pharmacol ・ mixed routes ・ not assessed
• Mitochondrial dysfunction, neuroinflammation, and associated mechanisms in sepsis-associated encephalopathy: from pathogenesis to emerging therapeutics.
  2026 ・ Front Neurosci ・ not specified ・ not assessed
• Effect of molecular hydrogen treatment on Sepsis-Associated encephalopathy in mice based on gut microbiota.
  2023 ・ CNS Neurosci Ther ・ mixed routes ・ positive
• Molecular hydrogen attenuates sepsis-induced cognitive dysfunction through regulation of tau phosphorylation.
  2023 ・ Int Immunopharmacol ・ inhalation ・ positive
• Hydrogen-rich saline regulates NLRP3 inflammasome activation in sepsis-associated encephalopathy rat model.
  2023 ・ Int Immunopharmacol ・ injection / infusion ・ positive
• Emerging Trends and Hot Spots in Sepsis-Associated Encephalopathy Research From 2001 to 2021: A Bibliometric Analysis.
  2022 ・ Front Med (Lausanne) ・ not specified ・ not assessed
• Hydrogen Gas Alleviates Sepsis-Induced Brain Injury by Improving Mitochondrial Biogenesis Through the Activation of PGC-α in Mice.
  2021 ・ Shock ・ inhalation ・ positive
• Hydrogen gas alleviates sepsis-induced neuroinflammation and cognitive impairment through regulation of DNMT1 and DNMT3a-mediated BDNF promoter IV methylation in mice.
  2021 ・ Int Immunopharmacol ・ inhalation ・ positive