Molecular hydrogen alleviates asphyxia-induced neuronal cyclooxygenase-2 expression in newborn pigs
Varga V, Németh J, Oláh O, Tóth-Szűki V, Kovács V, Remzső G, Domoki F. · Acta Pharmacologica Sinica. 2018;39(8):1273-1283.
What kind of evidence is this?
Preclinical
Pooled controlled histological analysis of two newborn-pig asphyxia experiments plus time controls
Other neurological conditions
Inhaled H₂
Not reported in this record.
Not reported in this record.
Methods at a glance
Fifty-nine newborn male Large-White piglets, using stored brain material from prior mild and severe asphyxia studies and additional control groups.
59 piglets overall. Each 8-minute and 20-minute experiment used time-control, asphyxia and asphyxia-plus-H₂ groups of n=7 each; additional naive controls were n=5 and four-hour normoxic controls n=12. Some secondary stains used n=6-7 per group.
Four hours of H₂ immediately after asphyxia, then 20 hours of room air; brain assessment at 24 hours.
After 8 or 20 minutes of experimental asphyxia, piglets inhaled room air containing 2.1% H₂ for four hours, followed by ordinary room air for the remaining 20-hour survival period.
Inhaled H₂ added to room air — not Brown's gas and not a co-generated H₂/O₂ mixture.
2.1% H₂ in room air. Total mixture flow, H₂ mL/min and O₂ mL/min were not reported in this article or reconstructable from the stated protocol.
Not reported — total chamber/ventilator flow and H₂ mL/min are absent.
Room air was the carrier; O₂ flow in mL/min was not reported and is not inferred.
Matching normoxic time controls and asphyxia groups without H₂ for each severity model, plus naive and shorter-duration normoxic controls.
Outcomes and reported result
Region-specific neuronal COX-2 immunopositivity, histopathology, neuronal 8-OHdG oxidative damage and microglial ramification.
Twenty-minute asphyxia increased neuronal COX-2 in selected cortex/CA3 regions and H₂ groups were similar to controls; H₂ was also associated with lower oxidative and microglial changes in selected analyses. Eight-minute asphyxia produced no significant COX-2 change, and several regions after severe asphyxia showed only non-significant trends or no change. This re-analysis did not test survival or neurodevelopment.
The complete free PMC article was checked for the source cohorts, allocations, asphyxia protocols, H₂ composition/timing, region-specific positive and null findings, funding and available declarations.
A reported association, difference or mechanism is not automatically a clinical benefit. Null findings, outcome type, study design and precision all matter.
Cautions and applicability
Secondary analysis of tissue from earlier experiments, small region-specific groups, many histological comparisons, male piglets only, no long-term functional endpoint and no reported gas flow. Hungarian/EU public grants funded the study; no explicit conflict declaration was identified, so absence is not inferred.
Experimental asphyxia in newborn piglets; it does not establish neonatal clinical efficacy or an inhalation protocol.
Not reported in this record.
Not reported in this record.
Not reported in this record.
No single-study GRADE certainty rating is assigned. Certainty is assessed by important outcome across a complete eligible evidence set, not by attaching a final grade to one source.
Sources and record status
PMID: 29565041 · DOI: 10.1038/aps.2017.148
Free full article in PubMed Central.
Complete PMC article and PubMed metadata; full-text extraction checked 9 August 2026.
2026-08-10