Polystyrene Nanoplastics Disrupt Mouse Placenta Development in a Sex-Dependent Manner.

Area of Science:

• Environmental Science
• Toxicology
• Reproductive Biology

Background:

• Exponential increase in plastic production leads to widespread environmental contamination.
• Plastic particles degrade into nanoplastics, accumulating in the body and crossing the placental barrier.
• The impact of nanoplastics on placental function remains largely unknown.

Purpose of the Study:

• To investigate the effects of nanoplastics on placental growth and function.
• To examine the impact of nanoplastics on transforming growth factor beta (TGFβ) signaling pathways.
• To determine if nanoplastics act as endocrine disruptors during pregnancy.

Main Methods:

• Pregnant mice were orally exposed to 50 nm or 200 nm polystyrene nanoplastics.
• Exposure occurred from gestation day 8 to day 15 at a human-relevant dose (5 mg/kg/day).
• Placental and fetal weights were measured; tissues underwent histomorphology and gene expression analysis.

Main Results:

• A significant decrease in decidua area was observed in placentas exposed to 200 nm nanoplastics, with a borderline effect for 50 nm.
• Sex-specific effects were noted, with male decidua significantly reduced in the 200 nm group.
• Increased expression of Smad2 and Smad3 genes suggests disruption of TGFβ signaling, potentially suppressing prolactin and estrogen receptor signaling.

Conclusions:

• Nanoplastics disrupt placental structure and TGFβ signaling in a sex-dependent manner.
• These disruptions may lead to adverse effects on fetal development.
• Nanoplastics exhibit endocrine-disrupting potential during pregnancy.