Polystyrene Microplastics Induce Sustained Cardiovascular Redox Imbalance and Alter Mitochondrial Quality Control

Area of Science:

• Environmental Health
• Cardiovascular Toxicology
• Mitochondrial Biology

Background:

• Microplastic exposure is a growing concern for cardiovascular health.
• The long-term cardiovascular effects after microplastic exposure cessation are not well understood.

Purpose of the Study:

• To investigate subclinical cardiovascular alterations after repeated oral exposure to polystyrene microplastics (PSMPs).
• To assess the roles of redox imbalance and mitochondrial dysfunction in delayed cardiovascular changes post-exposure.

Main Methods:

• Male Sprague-Dawley rats were gavaged with PSMPs (0.5 μm) at 5 or 20 mg/kg every 5 days for 70 days, followed by a 35-day exposure-free period.
• Cardiac serum markers, oxidative stress indicators (NOX4, SOD1, SOD2, CAT, MDA), mitochondrial respiratory chain activities (NCCR, SCCR), mitochondrial biogenesis proteins (PGC-1α, NRF-1, TFAM), and mitophagy markers (PINK1, Parkin, LC3, p62) were analyzed.
• Aortic oxidative stress and structural remodeling were also examined.

Main Results:

• PSMP exposure led to cardiac serum marker alterations and chronic low-level oxidative stress in cardiac tissue.
• Significant reductions in mitochondrial respiratory chain activities and disruptions in mitochondrial ultrastructure were observed.
• Downregulation of mitochondrial biogenesis and upregulation of mitophagy markers indicated impaired mitochondrial quality control.
• Aorta showed increased oxidative stress markers without overt remodeling.
• High-dose PSMP exposure resulted in more pronounced alterations.

Conclusions:

• Repeated PSMP exposure induces subclinical cardiac redox-mitochondrial dysregulation.
• These alterations persist after exposure cessation, highlighting potential long-term cardiovascular risks.
• The findings underscore the importance of addressing microplastic contamination for public cardiovascular health.