Microplastic polyethylene induced inner ear dysfunction in murine model.

Area of Science:

• Environmental Health
• Toxicology
• Neuroscience

Background:

• Microplastic (MP) pollution is a growing concern, with increasing reports on its hazardous effects.
• The impact of MPs on inner ear function, crucial for hearing and balance, remains largely unknown.
• Inner ear dysfunction is prevalent across all age groups, necessitating investigation into potential environmental triggers.

Purpose of the Study:

• To investigate the effects of polyethylene (PE) microplastic exposure on inner ear function in a murine model.
• To determine if PE MPs induce hearing loss and balance disorders.
• To explore the underlying molecular and metabolic changes in the inner ear and brain following PE exposure.

Main Methods:

• C57BL/6J mice were orally administered PE MPs daily for 4 months.
• Evaluated hearing thresholds, cerebral glucose metabolism, and balance-related behaviors.
• Conducted transcriptome analysis, qRT-PCR, Western blotting, and immunofluorescence staining to assess molecular changes.

Main Results:

• PE MPs were detected in the cochlea and vestibular region of the inner ear.
• PE exposure led to increased hearing thresholds and impaired balance.
• Transcriptomic analysis revealed the upregulation of PER1, NR4A3, and CEBPB in PE-exposed inner ear tissue.
• Decreased glucose metabolism was observed in auditory cortex regions and the entorhinal cortex.

Conclusions:

• Oral exposure to polyethylene microplastics induces inner ear dysfunction in mice.
• PE MPs can cause hearing loss and balance disorders.
• These findings suggest a direct link between microplastic exposure and neurosensory deficits.