Abstract The widespread application of zinc oxide nanoparticles (ZnO NPs) in multiple industrial fields has raised growing concerns about their potential adverse effects on human health, particularly during pregnancy. Among these concerns, reproductive toxicity and fetotoxicity have gained increasing attention. Quercetin (Que) is a naturally occurring flavonoid known for its potent antioxidant and free radical–scavenging activities. The present study investigated the protective role of Que against ZnO NPs-induced placental toxicity in pregnant rats. Animals were randomly divided into four groups: control, Que (50 mg/kg), ZnO NPs (200 mg/kg), and Que–ZnO NPs group. All treatments were administered via oral gavage. Exposure to ZnO NPs resulted in marked oxidative stress, activation of endoplasmic reticulum (ER) stress pathways, and increased apoptotic activity within placental tissues, accompanied by evident structural disruption. Immunohistochemical analysis revealed a pronounced upregulation of cleaved caspase-3 and downregulation of vascular endothelial growth factor expression in both the labyrinth and basal zones. Notably, Que pretreatment significantly attenuated these biochemical, molecular, and histological alterations. Collectively, these findings demonstrate that Que confers a protective effect against ZnO NPs-induced placental toxicity by modulating oxidative stress, ER stress responses, and apoptosis in pregnant rats.
Alshaikh et al. (Tue,) studied this question.