Ingested Polystyrene Nanospheres Translocate to Placenta and Fetal Tissues in Pregnant Rats: Potential Health Implications

Abstract

Recent studies in experimental animals found that oral exposure to micro- and nano-plastics (MNPs) during pregnancy had multiple adverse effects on outcomes and progeny, although no study has yet identified the translocation of ingested MNPs to the placenta or fetal tissues, which might account for those effects. We therefore assessed the placental and fetal translocation of ingested nanoscale polystyrene MNPs in pregnant rats. Sprague Dawley rats (N = 5) were gavaged on gestational day 19 with 10 mL/kg of 250 µg/mL 25 nm carboxylated polystyrene spheres (PS25C) and sacrificed after 24 h. Hyperspectral imaging of harvested placental and fetal tissues identified abundant PS25C within the placenta and in all fetal tissues examined, including liver, kidney, heart, lung and brain, where they appeared in 10–25 µm clusters. These findings demonstrate that ingested nanoscale polystyrene MNPs can breach the intestinal barrier and subsequently the maternal–fetal barrier of the placenta to access the fetal circulation and all fetal tissues. Further studies are needed to assess the mechanisms of MNP translocation across the intestinal and placental barriers, the effects of MNP polymer, size and other physicochemical properties on translocation, as well as the potential adverse effects of MNP translocation on the developing fetus.

Microplastics exposure: implications for human fertility, pregnancy and child health

“…A combination of in vitro , animal, and human ex vivo studies demonstrate placental cell uptake of MNPs is enhanced by smaller size and greater concentration ( 106 – 112 ). Observations in both maternal mice and rats exposed to PS-NPs during gestation, ranging in size from 20 to 500nm, demonstrated the presence of these particles in fetal liver ( 96 , 108 , 109 ), heart ( 96 , 109 ), brain ( 99 , 108 , 109 ), lung ( 108 , 109 ), and kidney ( 109 ). Interestingly, a similar exposure using PE-MPs (10-45µm) resulted in MP accumulation exclusively in fetal kidneys ( 110 ).…”

Moldable plastics (polycaprolactone) can be acutely toxic to developing zebrafish and activate nuclear receptors in mammalian cells

“…Recent work has shown the presence of nanoplastics and microplastics within the human placenta, and nanoplastics have been observed to cause damage to developing mammalian fetuses. [125][126][127][128] Our findings can instruct the design of more biocompatible PCL and other biomaterials, in general, by applying new approach methodologies and non-targeted bioassays to assess biocompatibility. [129][130][131] Zebrafish have been demonstrated as effective platforms for studying the foreign body response to biomaterials and developing engineered tissues because of their optically transparent transgenic lines and rapid development.…”

In Vivo Tissue Distribution of Polystyrene or Mixed Polymer Microspheres and Metabolomic Analysis after Oral Exposure in Mice

“…Exposing animals to MPs via the oral gastric route leads to the dissemination of MPs outside of the intestine, specifically the liver. 60 Additionally, several studies in humans, mice, chickens, rats, and zebrafish have shown MP and nanoplastic (NP) ingestion results in their accumulation in tissues such as the placenta, 61 liver, 48 , 57 and kidney. 62 , 63 The distribution into the liver caused metabolic changes in mice 30 , 61 and fish.…”

“… 60 Additionally, several studies in humans, mice, chickens, rats, and zebrafish have shown MP and nanoplastic (NP) ingestion results in their accumulation in tissues such as the placenta, 61 liver, 48 , 57 and kidney. 62 , 63 The distribution into the liver caused metabolic changes in mice 30 , 61 and fish. 34 , 64 , 65 These studies highlight how MPs can cross the intestinal barrier and can cause extraintestinal manifestations (e.g., inflammation and oxidative stress).…”