Chronic environmental exposure to polystyrene microplastics increases the risk of nonalcoholic fatty liver disease

Yujie Shi1, Runyang Hong1, Zhencheng Fan1

  • 1Yangzhou University Medical College, Yangzhou University, Yangzhou, Jiangsu Province 225009, China.

Toxicology
|January 26, 2025
PubMed

Insights

Chronic exposure to microplastics (MPs) causes nonalcoholic fatty liver disease (NAFLD) in mice. Positively charged MPs showed stronger effects, inducing liver cell senescence and ferroptosis via the HO-1/Nrf2 pathway.

Area of Science:

  • Environmental Science
  • Toxicology
  • Hepatology

Background:

  • Microplastics (MPs) are pervasive environmental pollutants with potential human health impacts.
  • Limited research exists on the long-term effects of microplastic exposure, particularly on liver health.
  • Polystyrene (PS) microplastics, including unmodified and positively charged variants, are common and warrant investigation.

Purpose of the Study:

  • To investigate the chronic in vivo effects of polystyrene microplastics on liver health in mice.
  • To elucidate the in vitro mechanisms underlying microplastic-induced liver damage.
  • To explore the role of cellular senescence and ferroptosis in microplastic-induced nonalcoholic fatty liver disease (NAFLD).

Main Methods:

  • Mice were exposed orally to unmodified PS MPs and positively charged PS-NH2 MPs (10 mg/L) for six months.
  • Human hepatocyte cells were treated with MPs (25 µg/mL) in vitro to study cellular mechanisms.
  • Analysis included liver function tests, lipid deposition assessment, gene expression profiling, and evaluation of senescence and ferroptosis markers.

Main Results:

  • Six-month MP exposure induced NAFLD, characterized by impaired liver function and extensive lipid accumulation.
  • Positively charged PS-NH2 MPs demonstrated a more pronounced effect than unmodified PS MPs.
  • MP exposure led to hepatocyte senescence and ferroptosis, mediated by the HO-1/Nrf2 pathway, evidenced by iron deposition and lipid peroxidation.

Conclusions:

  • Chronic microplastic exposure is linked to the development of nonalcoholic fatty liver disease.
  • The HO-1/Nrf2 pathway plays a critical role in mediating microplastic-induced ferroptosis and subsequent cell senescence.
  • Targeting the HO-1/Nrf2 pathway offers a potential therapeutic strategy to mitigate microplastic-induced liver damage.