# The effect of Hydrogen-rich water on retinal degeneration in the outer nuclear layer of simulated weightlessness rats.
> 模擬無重力環境下ラットの網膜外核層変性に対する水素水の影響


## Abstract

This animal study investigated whether hydrogen-rich water (HRW) could protect against retinal damage induced by simulated microgravity. Using an 8-week tail-suspension model in rats, researchers assessed retinal structure and function via histopathology, visual electrophysiology, and biochemical markers. Simulated weightlessness produced thinning of the retinal outer nuclear layer, reduced visual function, and elevated markers of inflammation, oxidative stress, and mitochondrial dysfunction. HRW administration attenuated these degenerative changes, restored retinal function, and lowered inflammatory indices. Mechanistically, HRW activated the PI3K/Akt/Nrf2 signaling pathway, thereby suppressing oxidative stress and improving mitochondrial performance. These findings suggest HRW as a candidate intervention for microgravity-associated ocular injury.

### Mechanism

HRW activates the PI3K/Akt/Nrf2 signaling cascade, reducing retinal oxidative stress responses and restoring mitochondrial function in tail-suspension-induced simulated weightlessness rats.

## Bibliographic

- **Authors**: Mu Y, Li W, Wei D, Zhang XQ, Yao L, Xu XY, et al.
- **Journal**: Life Sci Space Res (Amst)
- **Year**: 2025
- **PMID**: [40280637](https://pubmed.ncbi.nlm.nih.gov/40280637/)
- **DOI**: [10.1016/j.lssr.2025.03.004](https://doi.org/10.1016/j.lssr.2025.03.004)
- **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 40280637. https://h2-papers.org/en/papers/40280637
> **Source**: PubMed PMID [40280637](https://pubmed.ncbi.nlm.nih.gov/40280637/)