Ototoxicity of polystyrene nanoplastics in mice, HEI-OC1 cells and zebrafish.
Level 5 - mechanism / opinion, no new human data
Preclinical animal (mice, zebrafish) and in vitro cellular research without human data.
PubMed 38440220 · doi:10.3389/fnmol.2024.1345536
What was done
The authors evaluated the ototoxic effects and underlying mechanisms of polystyrene nanoplastics across three models: mice, cultured HEI-OC1 auditory cells, and zebrafish. They assessed nanoplastic uptake, cellular apoptosis, mouse auditory brainstem response (ABR) thresholds, auditory hair cell and stereocilia integrity, blood-lymphatic barrier proteins (Claudin-5, Occludin), zebrafish acoustic alarm behavior, oxidative stress markers, ferroptosis markers, inflammatory mediators, and rescue effects following N-acetylcysteine (NAC) pretreatment.
What was found
The abstract reports directional findings without specific numerical values. Polystyrene nanoplastics entered auditory cells and tissues across all models, increasing apoptosis and cellular injury. In mice, exposure increased ABR hearing thresholds, induced sensory hair cell loss and stereocilia degeneration, and reduced blood-lymphatic barrier proteins Claudin-5 and Occludin. In zebrafish, acoustic alarm responses decreased. In cochlear tissue and HEI-OC1 cells, exposure increased malondialdehyde, ACSL4, TNF-α, IL-1β, and COX2, upregulated the Nrf2/HO-1 pathway, and decreased SOD, catalase, GPX4, and SLC7A11 levels. NAC pretreatment reversed the nanoplastic-induced apoptosis, ferroptosis, and inflammation in HEI-OC1 cells.
Why it matters
This study provides initial preclinical evidence that environmental polystyrene nanoplastics can enter auditory organs and trigger hearing deficits via oxidative damage, ferroptosis, and local inflammation.
Limits
The findings are limited to animal and cell culture models, so real-world human exposure risk and clinical ototoxicity remain unknown. The abstract does not report specific sample sizes, plastic particle concentrations or dimensions, exposure durations, or quantitative effect sizes.
Cited by
- supports When inner ear tissue is exposed to micro- and nanoplastics, they are preferentially taken up by hair cells.