Effects of rotenone exposure during pregnancy on GSK-3β and β-catenin protein expression in rat placenta

BackgroundResearch on non-target organ damage of biological pesticides has attracted much attention. Rotenone exposure may be far beyond the occupational environment, and the exposureduring pregnancy may be increased through bioaccumulation, fruit or vegetable residues, and other forms of oral intake. At present, the effects of rotenone on placental development and its mechanism are still unknown. ObjectiveTo investigate the developmental damage of rat placenta and evaluate the expression levels of glycogen synthase kinase (GSK-3β) and beta catenin (β-catenin) followed by rotenone exposure through the placental barrier during pregnancy, as well as to propose possible associated mechanisms. MethodsEighteen sexually mature SD female infertile rats without specific pathogens were selected and divided into three groups: blank control group (0.9% saline), corn oil group, and rotenone group (corn oil + 2 mg·kg−1 rotenone) by random number method, six female animals in each group. Another six male rats were selected and mated to the female rats at night with a female to male ratio of 3:1 per cage. Pregnant rats were given 0.9% saline, corn oil, and 2 mg·kg−1 rotenone preparation by isovolumetric gavage once daily for the entire gestation period (19 d), and their conditions were observed after the last dose. The pregnant rats were anesthetized, and the size of the placenta and blood perfusion were detected by ultrasound the next day of the last dose of rotenone. Then, 3 pregnant rats in each group were sacrificed immediately and the placenta and umbilical cord tissues were dissected. The remaining 9 pregnant rats gave birth naturally, and the fetuses were observed for developmental evaluation and weighed. The histopathological changes of umbilical cord and placenta were observed by hematoxylin-eosin staining. The reactive oxygen species levels of placenta tissues were detected by flow cytometry. The Ca2+-ATPase activity of placenta tissues was detected by colorimetric method. The localization and levels of GSK-3β and β-catenin expression of placenta were detected by immunohistochemistry. The p-GSK-3β/GSK-3β and p-β-catenin/β-catenin protein expression in placental tissues were measured by Western blotting. ResultsNo injury or death was recorded during the pregnant rats receiving rotennon administration. Adverse pregnancy outcomes such as fetal absorption and postpartum stillbirth were found in the rotenone group, and the weight of the fetal mice decreased (P