Exposure Of Pregnant Dams Research Articles

P.234 Exposure of pregnant dams to prenatal stress: enhanced vulnerability, and long-lasting alterations in the offspring

P.234 Exposure of pregnant dams to prenatal stress: enhanced vulnerability, and long-lasting alterations in the offspring

Teratogenic effects of imidacloprid in rats: mechanistic role of oxidative stress

Extensive use of imidacloprid (IMI) insecticide in the agro-vet practices leads to continuous animal and human exposure. Exposure of pregnant dams to such insecticides results in fetal malformations. In the light of this, the present study was designed to investigate the teratogenic effects of two different doses of IMI and the possible mechanistic role of oxidative stress. Fifteen pregnant females were randomly divided into three equal groups and orally treated daily during organogenesis period (6-15th GD), control (distilled water), LD-IMI (45 mg/kg) and HD-IMI (90 mg/kg). All pregnant dams were exposed to caesarean section on GD 20. Exposure to IMI induced significant increase in the percentage of resorptions at high-dose with significant reduction of fetal and placental weights in a dose-dependent manner. External fetal morphological abnormalities were recorded only at high-dose while several visceral abnormalities were observed in fetuses at low- and high-doses. Significant increases in the percentages of fetal skeletal malformations were recorded only in the high-dose group. Significant changes in MDA, GSH levels and CAT activity with insignificant change in the level of H2O2 were recorded only in placentae of LD-IMI group. However, all these parameters recorded significant changes in serum of dams, placentae and liver of fetuses at high-dose. In conclusion, exposure of pregnant rats to IMI, particularly at higher-dose, during the period of organogenesis induced fetal teratogenic effects that may be related to its maternal and fetal oxidative damaging impacts.  Â

Gestational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin induces developmental defects in the rat vagina.

At puberty, female rats exposed in utero to 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) exhibit a persistent thread of mesenchymal tissue surrounded by keratinized epithelium that partially occludes the vaginal opening. Our objective was to determine the earliest time during fetal development that morphological signs of this vaginal canal malformation could be detected and to obtain greater insight into mechanisms involved in this effect. Pregnant rats were administered a single dose of vehicle (control) or TCDD (1.0 microg/kg, po) on gestation day (GD) 15 and were sacrificed on GD 18, 19, 20, and 21 for histological evaluation of female. Gestational exposure to TCDD affected vaginal morphogenesis as early as GD 19, 4 days after exposure of pregnant dams. In exposed fetuses, the thickness of mesenchymal tissue between the caudal Mullerian ducts was increased, which resulted in a failure of the Mullerian ducts to fuse, a process normally completed prior to parturition. In addition, TCDD exposure appeared to inhibit the regression of Wolffian ducts. Thus, TCDD interferes with vaginal development by impairing regression of the Wolffian ducts, by increasing the size of interductal mesenchyme, and by preventing fusion of the Mullerian ducts. Taken together, these effects appear to cause the persistent vaginal thread defect observed in rats following in utero and lactational TCDD exposure.