648 Utilizing primary human tissue/cell models to assess for pesticide-induced placental toxicity

Abstract

Chorionic villi serve as the primary interface between mother and fetus. Dysfunction at this interface is implicated in pregnancy complications. Pesticides are widely used in agriculture and vector control, but the full impact on human pregnancy is unknown. Specific pesticides such as organophosphate pesticides (OPs) are suspected to target the developing central nervous system and placenta. We aimed to leverage ex vivo models of the human placenta (primary chorionic villous explants and isolated cytotrophoblasts (CTBs)) for in vitro studies of toxicological agents. Isolated CTBs from 2nd trimester placentas were exposed to 9 diverse pesticides at 5 concentrations and compared to vehicle (0.1% DMSO) and media-only controls. At 24h, viability and cell death were assayed by neutral red lysosomal uptake or lactate dehydrogenase activity, respectively. Benchmark concentrations (BMC10) of a 10% change in cytotoxicity were identified to assess relative potencies. Human chorionic villi explants dissected from placentas were exposed to naled or vehicle for 24h. After exposure, 1st trimester villi were evaluated by gross morphology and 2nd trimester villi by histopathology and immunofluorescence. Sections were scored by 2 blind evaluators for syncytiotrophoblast (STB) denudation, quantified by ImageJ analysis. We used ANOVA and Tukey’s test to determine significant changes between groups. We observed concentration-dependent cytotoxicity with the three OPs (naled, dichlorovos and malathion) in CTBs (p<0.05; Figure 1). Naled was the most toxic pesticide. Gross morphologic evaluation of naled-exposed villi showed frayed appearance and impaired vascularity compared to the control groups. Naled-exposed explants displayed a ∼4-fold increase in STB denudation compared with media-only or vehicle controls (p<0.001, Figure 2). Our results suggest that naled, an OP commonly-used in agriculture and mosquito control is particularly toxic in two human placental models. We demonstrate that primary cell/tissue models can be used to evaluate placental toxicity of pesticide compounds.View Large Image Figure ViewerDownload Hi-res image Download (PPT)