Hydrogen gas inhalation improves delayed brain injury by alleviating early brain injury after experimental subarachnoid hemorrhage
Kumagai K et al. · Sci Rep. 2020;10:12319.
Study at a glance
Preclinical
Rats with experimental subarachnoid hemorrhage and unilateral common-carotid occlusion
Inhalation on days 0 and 1: 2 hours on day 0 and 30 minutes on day 1 · 1.3% H₂, 30% O₂ and nitrogen balance.
Two inhalation sessions with outcomes through day 7
The article reports improvement in early and delayed brain-injury measures. Cerebral vasospasm did not improve significantly.
Complex animal model, attrition into smaller outcome cohorts, multiple laboratory endpoints and no human participants. The null vasospasm result is retained.
What kind of evidence is this?
Preclinical
Controlled rat subarachnoid-hemorrhage plus carotid-occlusion experiment
Other neurological conditions
Inhaled H₂
Information not yet classified
Some editorial classification fields are still pending. The source-reported outcomes and result are shown below; Hydrogenology does not infer a positive or negative signal from prose automatically.
Methods
Rats with experimental subarachnoid hemorrhage and unilateral common-carotid occlusion
101 rats entered the protocol: sham n=31, control n=35 and H₂ n=33; later outcome cohorts were smaller
Two inhalation sessions with outcomes through day 7
Inhalation on days 0 and 1: 2 hours on day 0 and 30 minutes on day 1
H₂ diluted in oxygen and nitrogen — not Brown’s gas.
1.3% H₂, 30% O₂ and nitrogen balance.
Not reported — concentration is given, but H₂ flow in mL/min is not.
30% O₂ was co-delivered; O₂ flow in mL/min was not reported.
30% O₂ with nitrogen balance, without H₂, plus sham surgery
Outcomes and reported result
Brain edema, neurological deficits, S100B, JNK, astrogliosis, vasospasm and neuronal death
The article reports improvement in early and delayed brain-injury measures. Cerebral vasospasm did not improve significantly.
Gas composition, allocation, figures and positive and null results checked in the open-access full text.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Complex animal model, attrition into smaller outcome cohorts, multiple laboratory endpoints and no human participants. The null vasospasm result is retained.
Experimental subarachnoid hemorrhage with added carotid occlusion in rats, not patients with aneurysmal hemorrhage.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 32704088 · DOI: 10.1038/s41598-020-69028-5
Open-access full text is available through PMC.
Open-access PMC full text and PubMed record.
10 August 2026
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