# Regulation of microRNAs by molecular hydrogen contributes to the prevention of radiation-induced damage in the rat myocardium.
> 分子状水素によるマイクロRNA制御が放射線誘発性ラット心筋障害の予防に果たす役割


## Abstract

MicroRNAs (miRNAs) are post-transcriptional regulators implicated in radiation-induced cardiac pathology. This rat study examined whether hydrogen-rich water (HRW) influences myocardial miRNA-1, -15b, and -21 following thoracic irradiation. Irradiation elevated malondialdehyde (MDA) and TNF-α in the myocardium; HRW administration normalized both markers to levels comparable with non-irradiated controls. miRNA-1, associated with cardiac hypertrophy, was reduced by irradiation, and HRW attenuated this reduction across all assessed time points. miRNA-15b, which carries anti-fibrotic and antioxidative properties, was similarly downregulated by irradiation but restored by HRW. Conversely, miRNA-21, linked to cardiac fibrosis, was elevated after irradiation, and HRW lowered its expression. These findings provide the first evidence that myocardial protection by molecular hydrogen after irradiation may be mediated through differential regulation of specific miRNAs.

### Mechanism

HRW reduces MDA and TNF-α while normalizing radiation-altered miRNA expression—restoring downregulated miRNA-1 and miRNA-15b and suppressing upregulated miRNA-21—thereby attenuating oxidative stress, inflammation, and fibrosis-related signaling in the irradiated myocardium.

## Bibliographic

- **Authors**: Kura B, Kalocayova B, LeBaron TW, Frimmel K, Buday J, Surovy J, et al.
- **Journal**: Mol Cell Biochem
- **Year**: 2019
- **PMID**: [30830529](https://pubmed.ncbi.nlm.nih.gov/30830529/)
- **DOI**: [10.1007/s11010-019-03512-z](https://doi.org/10.1007/s11010-019-03512-z)
- **Study type**: animal study
- **Delivery route**: hydrogen-rich water
- **Effect reported**: positive

## Delivery context

Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

## Safety notes

Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; high-concentration devices are documented in the Consumer Affairs Agency accident 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)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 30830529. https://h2-papers.org/en/papers/30830529
> **Source**: PubMed PMID [30830529](https://pubmed.ncbi.nlm.nih.gov/30830529/)