Hydrogen inhalation protects hypoxic–ischemic brain damage by attenuating inflammation and apoptosis in neonatal rats
Wu G, Chen Z, Wang P, Zhao M, Fujino M, Zhang C, Zhou W, Hirano SI, Li XK, Zhao L. · Experimental Biology and Medicine. 2019;244(12):1017-1027.
Study at a glance
Preclinical
One hundred forty male and female postnatal-day-7 Sprague-Dawley rats in a carotid-ligation plus hypoxia model.
After hypoxic-ischemic injury, pups inhaled 3% H₂ in 97% air for 30, 60 or 90 minutes; a separate group began 90-minute treatment two hours late. The methods state exposure occurred twice daily before the acute sacrifices. · 3% H₂ and 97% air. The article does not report total gas flow, chamber turnover, H₂ flow in mL/min or O₂ flow in mL/min; those values cannot be reconstructed reliably.
Acute assessments at 24 and 72 hours; Morris water-maze testing on postnatal days 43-47.
Longer H₂ exposures were generally associated with smaller infarcts, less inflammation/apoptosis and better later maze performance, and immediate treatment outperformed the two-hour delay. The 30-minute exposure did not significantly reduce cortical Iba1 versus HIBD (p=0.055), and H₂ did not shorten first-day maze escape latency (p>0.05). Naive and sham groups did not differ on several acute assays.
Neonatal-rat model with no standard-treatment comparison, multiple molecular endpoints, incomplete gas-delivery engineering data, and limited examination of sex effects and other brain immune cells. Chinese institutional/provincial grants funded the work; authors declared no conflicts.
What kind of evidence is this?
Preclinical
Randomized seven-group neonatal-rat duration and delayed-start 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
One hundred forty male and female postnatal-day-7 Sprague-Dawley rats in a carotid-ligation plus hypoxia model.
140 rats: naive n=22, sham n=22, HIBD n=22, immediate H₂ for 30 minutes n=22, 60 minutes n=22, 90 minutes n=22, and delayed-start 90-minute H₂ n=8. Twelve per principal group were assigned to pathology/molecular work and ten to neurobehavioral testing.
Acute assessments at 24 and 72 hours; Morris water-maze testing on postnatal days 43-47.
After hypoxic-ischemic injury, pups inhaled 3% H₂ in 97% air for 30, 60 or 90 minutes; a separate group began 90-minute treatment two hours late. The methods state exposure occurred twice daily before the acute sacrifices.
Inhaled H₂ mixed with air — H₂ alone was added; this was not Brown's gas or a co-generated H₂/O₂ mixture.
3% H₂ and 97% air. The article does not report total gas flow, chamber turnover, H₂ flow in mL/min or O₂ flow in mL/min; those values cannot be reconstructed reliably.
Not reported — neither total mixture flow nor H₂ mL/min is stated.
Air was the carrier. O₂ percentage and O₂ mL/min were not separately reported; no value is inferred.
Naive, sham-surgery and untreated hypoxic-ischemic groups, plus comparisons among exposure durations and immediate versus two-hour delayed start.
Outcomes and reported result
Infarct volume, Nissl injury, microglial activation, inflammatory and apoptotic markers, TUNEL/NeuN, and adolescent spatial learning/memory.
Longer H₂ exposures were generally associated with smaller infarcts, less inflammation/apoptosis and better later maze performance, and immediate treatment outperformed the two-hour delay. The 30-minute exposure did not significantly reduce cortical Iba1 versus HIBD (p=0.055), and H₂ did not shorten first-day maze escape latency (p>0.05). Naive and sham groups did not differ on several acute assays.
The complete free PMC article was checked for all seven groups, sex counts, gas composition, timing, delayed-start arm, acute and long-term outcomes, null results, stated limitations, funding and conflict declaration.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Neonatal-rat model with no standard-treatment comparison, multiple molecular endpoints, incomplete gas-delivery engineering data, and limited examination of sex effects and other brain immune cells. Chinese institutional/provincial grants funded the work; authors declared no conflicts.
Neonatal hypoxic-ischemic brain injury in rats; it does not establish neonatal clinical efficacy, safety or a human inhalation protocol.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 31189349 · DOI: 10.1177/1535370219855399
Free full article in PubMed Central.
Complete PMC article and PubMed metadata; full-text extraction checked 9 August 2026.
10 August 2026
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