Hydrogen coadministration slows the development of COPD-like lung disease in a cigarette smoke-induced rat model.
Liu X, Ma C, Wang X, Wang W, Li Z, Wang X, Wang P, Sun W, Xue B. · 2017.
What kind of evidence is this?
Preclinical
Controlled rat dose-comparison study
Respiratory health
Inhaled H₂
Positive preclinical signal with non-linear dose findings.
Animal physiological, tissue and mechanistic outcomes.
Methods at a glance
Rats in a cigarette-smoke-induced COPD-like lung-disease model.
Animal groups and assay counts were checked in the full article.
Repeated exposure during development of the COPD-like model.
Inhalation of 2%, 22% or 41.6% hydrogen during smoke exposure.
Inhaled molecular H₂ at three concentrations.
2%, 22% and 41.6% H₂; absolute gas flows require the linked methods.
No single separately verified H₂ flow is reported here.
Carrier-gas composition varies by arm; no Brown's-gas label is inferred.
Smoke-exposed controls and multiple H₂ concentrations.
Outcomes and reported result
Lung function, pulmonary pressure, histology, inflammatory cells, cytokines, proteases and apoptosis markers.
Hydrogen groups were reported to have better lung and cardiovascular measures and lower inflammatory or apoptotic markers, with some higher-concentration outcomes stronger than 2%.
The full article was checked for methods, intervention details, outcomes, positive and null findings, funding and conflicts. This record does not imply medical efficacy.
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
Animal model with unusually high gas concentrations, many outcomes and no basis for selecting a human dose.
The reported smoke-exposed rat model only.
SYRCLE animal-study tool — preliminary
Some concerns
Dose controls were present, but concealment, blinded assessment and multiplicity handling were not fully established.
Sequence generation checked where reported · Allocation concealment generally unclear · Personnel blinding generally unclear · Outcome-assessor blinding generally unclear · No prospectively registered analysis plan identified
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: 28496315 · DOI: 10.2147/copd.s124547
A free full article is available through PubMed Central.
Official PubMed Central full article and PubMed bibliographic record; source identity, methods, intervention, results, funding and conflicts checked 10 August 2026.
2026-08-10