Molecular Hydrogen Attenuated N-methyl-N-Nitrosourea Induced Corneal Endothelial Injury by Upregulating Anti-Apoptotic Pathway
Li R, Qu Y, Li X, Tao Y, Yang Q, Wang J, Diao Y, Li Q, Fang Y, Huang Y, Wang L. · Investigative Ophthalmology & Visual Science. 2021;62(9):2.
Study at a glance
Preclinical
New Zealand rabbits with one eye injured by anterior-chamber N-methyl-N-nitrosourea injection; cultured corneal endothelial cells were used for mechanistic experiments.
Rabbit eyes were irrigated with freshly prepared hydrogen-rich saline three times daily for 3 minutes at 3 drops/second during the week before and the week after MNU injection; cells received H₂-containing medium together with MNU. · An SFH-300 generator supplied H₂ to 100 mL saline or medium at 0.4 MPa; solutions were stored sealed at 4°C for 24 hours and measured at greater than 1.2 ppm H₂ before use.
Topical irrigation for 14 days spanning one week before and one week after MNU; rabbit outcomes were followed through day 28.
Hydrogen-rich saline was associated with less corneal edema and endothelial injury and with lower apoptosis and oxidative-stress measures. Central corneal thickness did not differ from saline at day 1 (p=0.5391) or day 7 (p=0.1569), but did at days 3, 14, 21 and 28; the cell assays also reported changes consistent with reduced apoptosis.
Preclinical chemically induced injury rather than naturally occurring human corneal disease, topical pretreatment began before injury, rabbit corneal endothelium has greater regenerative capacity than human endothelium, and multiple animal and cell outcomes were tested. The article's n=8 protocol and n=18 figure labels are not reconciled. Authors disclosed no conflicts; no dedicated funding statement was identified in the checked article, so absence of funding is not inferred.
What kind of evidence is this?
Preclinical
Controlled rabbit-eye injury experiment with complementary cultured corneal-endothelial-cell assays
Other molecular hydrogen research
Other forms
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
New Zealand rabbits with one eye injured by anterior-chamber N-methyl-N-nitrosourea injection; cultured corneal endothelial cells were used for mechanistic experiments.
The animal protocol reports n=8 rabbits/eyes per irrigation condition, while several figure analyses report n=18 measurements without clarifying whether these are independent eyes, fields or repeated measures; Hydrogenology does not merge these into one inferred sample size.
Topical irrigation for 14 days spanning one week before and one week after MNU; rabbit outcomes were followed through day 28.
Rabbit eyes were irrigated with freshly prepared hydrogen-rich saline three times daily for 3 minutes at 3 drops/second during the week before and the week after MNU injection; cells received H₂-containing medium together with MNU.
H₂ dissolved in saline or culture medium — H₂ only, not Brown's gas and not inhalation.
An SFH-300 generator supplied H₂ to 100 mL saline or medium at 0.4 MPa; solutions were stored sealed at 4°C for 24 hours and measured at greater than 1.2 ppm H₂ before use.
MNU-injured eyes irrigated with ordinary saline or not irrigated, the contralateral unoperated eye as normal control, and matched cell-culture controls.
Outcomes and reported result
Slit-lamp and anterior-segment OCT findings, central corneal thickness, endothelial morphology and density, apoptosis, reactive oxygen species, 8-OHdG, ZO-1 and Na⁺/K⁺-ATPase, and NF-κB/NLRP3 and FOXO3a/p53/p21 pathway measures.
Hydrogen-rich saline was associated with less corneal edema and endothelial injury and with lower apoptosis and oxidative-stress measures. Central corneal thickness did not differ from saline at day 1 (p=0.5391) or day 7 (p=0.1569), but did at days 3, 14, 21 and 28; the cell assays also reported changes consistent with reduced apoptosis.
The complete open-access article, rabbit and cell protocols, H₂ preparation and measured concentration, positive and null time-point findings, disclosure statement and methodological ambiguities were checked.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Preclinical chemically induced injury rather than naturally occurring human corneal disease, topical pretreatment began before injury, rabbit corneal endothelium has greater regenerative capacity than human endothelium, and multiple animal and cell outcomes were tested. The article's n=8 protocol and n=18 figure labels are not reconciled. Authors disclosed no conflicts; no dedicated funding statement was identified in the checked article, so absence of funding is not inferred.
Experimental rabbit corneal injury and cultured cells; it does not establish efficacy or safety of ocular hydrogen-rich saline in people.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 34196654 · DOI: 10.1167/iovs.62.9.2
Open-access IOVS article and PubMed Central copy.
Complete PubMed Central/IOVS article and PubMed metadata; full-text extraction checked 9 August 2026.
10 August 2026
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