Polyethylene microplastic exposure adversely affects oocyte quality in human and mouse

Area of Science:

• Reproductive Biology
• Environmental Health
• Toxicology

Background:

• Microplastics (MPs) are widespread environmental pollutants with increasing human exposure.
• Oocyte quality is crucial for successful fertilization and reproductive outcomes.
• The impact of microplastics on human reproductive health, particularly oocytes, requires further investigation.

Purpose of the Study:

• To identify microplastics in human follicular fluid and assess their association with oocyte quality.
• To investigate the effects of polyethylene (PE) microplastics on oocyte quality and underlying mechanisms using a mouse model.
• To explore the impact of PE on follicular fluid metabolism and gene expression.

Main Methods:

• Raman microspectroscopy to detect and identify MPs in follicular fluid from infertile women.
• Untargeted metabolomics to analyze differential metabolites in follicular fluid.
• Exposure of female mice to PE microplastics to evaluate effects on oocyte retrieval, fertilization, quality, and ROS production.
• RNA sequencing to assess gene expression changes in response to PE exposure.

Main Results:

• Polyethylene (PE) MPs were detected in 86.4% of human follicular fluid samples, negatively correlating with fertilization rates.
• PE exposure in mice reduced oocyte yield and fertilization rates, increased poor-quality oocytes, and elevated ROS production.
• PE altered key metabolites in follicular fluid and upregulated inflammation-related genes in oocytes.

Conclusions:

• Polyethylene microplastics in follicular fluid adversely affect oocyte quality and fertilization potential.
• PE exposure may impair oocyte quality through disruption of follicular fluid metabolism, increased inflammation, and elevated oxidative stress.
• These findings highlight the potential reproductive risks associated with microplastic contamination.