# Hydrogen-rich water reduced oxidative stress and renal fibrosis in rats with unilateral ureteral obstruction.
> 水素水経口摂取による一側尿管閉塞ラットの酸化ストレス軽減および腎線維化抑制効果


## Abstract

Congenital obstructive nephropathy is a leading contributor to chronic kidney disease in pediatric populations, with reactive oxygen species playing a central role in driving renal fibrosis. Using a rat unilateral ureteral obstruction (UUO) model, this study examined whether oral hydrogen-rich water (HW) could mitigate renal injury. Male Sprague-Dawley rats underwent UUO surgery and received either distilled water or HW for two weeks. Histopathological and immunohistochemical analyses revealed that UUO kidneys exhibited widened interstitial spaces and tubular dilation. HW administration significantly reduced tubulointerstitial injury and interstitial fibrotic area, accompanied by decreased numbers of α-SMA-, ED-1-, and TGF-β1-positive cells compared with the distilled water group. Additionally, the decline in klotho mRNA expression was less pronounced in HW-treated animals, suggesting klotho involvement in the protective mechanism. These findings indicate that oral HW intake can attenuate oxidative stress-driven renal fibrosis in obstructive nephropathy models.

### Mechanism

Hydrogen-rich water is proposed to scavenge reactive oxygen species, thereby reducing oxidative stress. This leads to decreased TGF-β1 and α-SMA expression, fewer infiltrating macrophages (ED-1-positive cells), and preservation of klotho mRNA levels, collectively suppressing interstitial fibrosis in obstructed kidneys.

## Bibliographic

- **Authors**: Mizutani A, Endo A, Saito M, Hara T, Nakagawa M, Sakuraya K, et al.
- **Journal**: Pediatr Res
- **Year**: 2022
- **PMID**: [34365467](https://pubmed.ncbi.nlm.nih.gov/34365467/)
- **DOI**: [10.1038/s41390-021-01648-7](https://doi.org/10.1038/s41390-021-01648-7)
- **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 34365467. https://h2-papers.org/en/papers/34365467
> **Source**: PubMed PMID [34365467](https://pubmed.ncbi.nlm.nih.gov/34365467/)