# Development of a novel porcine ischemia/reperfusion model inducing different ischemia times in bilateral kidneys-effects of hydrogen gas inhalation.
> 左右腎臓に異なる虚血時間を導入した新規ブタ虚血再灌流モデルの開発と水素ガス吸入の効果


## Abstract

To investigate renal ischemia-reperfusion injury (IRI), a novel porcine model was developed in which the left and right kidneys were subjected to 120 and 60 minutes of ischemia, respectively, within the same animal. All four animals survived the 3-month observation period without mortality. Separate evaluation of each kidney was achieved through individual renal vein blood sampling and intraoperative biopsy. Degraded DNA released from the kidneys immediately after IRI and subsequent renal fibrosis at 3 months both increased proportionally with ischemia duration. Hydrogen gas inhalation showed a tendency to suppress the release of degraded DNA—an acute IRI marker—although this effect did not reach statistical significance. Histopathological differences between hydrogen-treated and control animals were not clearly evident. This bilateral differential-ischemia model provides two independent data points per animal and enables safe long-term porcine experiments.

### Mechanism

Inhaled hydrogen gas showed a trend toward reducing degraded DNA release from kidneys following ischemia-reperfusion, suggesting possible reactive oxygen species scavenging as a mechanism underlying acute renal IRI attenuation.

## Bibliographic

- **Authors**: Kinoshita Y, Shirakawa K, Sano M, Yokoo T, Kume H, Kobayashi E
- **Journal**: Transl Androl Urol
- **Year**: 2022
- **PMID**: [35558259](https://pubmed.ncbi.nlm.nih.gov/35558259/)
- **DOI**: [10.21037/tau-21-1164](https://doi.org/10.21037/tau-21-1164)
- **PMC**: [PMC9085936](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9085936/)
- **Study type**: animal study
- **Delivery route**: inhalation
- **Effect reported**: mixed

## Delivery context

For inhalation applications of molecular hydrogen, the lower flammability limit (LFL) deserves careful handling. The classical 4% figure applies to closed-system mixtures; the practical inhalation-environment threshold is 10%. Even pure-hydrogen output (the UFL 75% paradox) passes through the flammable range at the air–gas boundary. High-concentration (66% / 100%) inhalers are documented in the Japanese Consumer Affairs Agency accident-information database and are not recommended.

## Safety notes

For inhalation applications of molecular hydrogen, the lower flammability limit (LFL) deserves careful handling. The classical 4% figure applies to closed-system mixtures; the practical inhalation-environment threshold is 10%. Even pure-hydrogen output (the UFL 75% paradox) passes through the flammable range at the air–gas boundary. High-concentration (66% / 100%) inhalers are documented in the Japanese Consumer Affairs Agency accident-information database and are not recommended.

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [LFL / UFL terminology](https://h2-papers.org/en/safety-notes/lfl-ufl-explained)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 35558259. https://h2-papers.org/en/papers/35558259
> **Source**: PubMed PMID [35558259](https://pubmed.ncbi.nlm.nih.gov/35558259/)