The effect of Ipomoea carnea on maternal reproductive outcomes and fetal and postnatal development in rats

Ipomoea carnea is a toxic plant found in Brazil and other tropical countries. The plant contains the alkaloids calystegines and swainsonine, which inhibit key cellular enzymes and cause systematic cell death. It is known that swainsonine is excreted in the amniotic fluid of dams exposed to the plant. Thus, the aim of this study was to verify whether the toxic effect of I. carnea on fetuses is due to exclusively the passage of the active principle of the plant through the placenta, or if the placentotoxic effect of swainsonine could collaborate in the adverse effects observed in the fetus. The teratogenic effects of exposure to the toxic principles of I. carnea were evaluated not only using the conventional protocol but also at later stages in the postnatal developmental period. Females were treated, from gestation day (GD) 6 until GD19, with 0.0, 1.0, 3.0 or 7.0 g/kg body weight of I. carnea dry leaves. The plant did not induce changes in reproductive performance or biochemical profile of the dams. Dams that received the highest dose of I. carnea showed cytoplasmic vacuolization in the liver, kidney and placental tissue. I. carnea promoted different lectin binding patterns in different areas of placental tissue. No fetal skeletal or visceral malformations was observed. The postnatal evaluation revealed a lower litter weight and a lower pup body weight one day after birth in the group that received the highest dose of I. carnea. Physical milestones were unaffected by the treatments. Female pups from all experimental groups exhibited a delay in achieving a negative geotaxis response. The results show that the toxic principle of I. carnea produces injury in utero in mothers and fetuses, but these deleterious effects were better demonstrated using postnatal evaluation.

Enhanced thymocyte apoptosis induced by maternal undernutrition in late gestation results in declined mature T cells in rat fetal thymus

This study was designed to observe the effects of maternal food restriction (MFR) on the development of fetal thymus in different gestation periods. Timed pregnant rats were randomized into 3 groups: CN (free access to standard chow throughout gestation), MFR_0-21 (50% MFR throughout gestation), MFR_0-14 (50% MFR from gestational day (GD) 0 to GD14, early-mid gestation). Results showed that MFR during early-mid period had few impact on the fetal thymus and T cell subpopulations. However, MFR throughout gestation resulted in thymic atrophy, deceased frequency of both CD4⁺ and CD8⁺ single positive (SP) T cells and enhanced thymocyte apoptosis in fetus. Our results suggest the fetal thymus is more vulnerable to the adverse intrauterine environments in the late gestation period, and the decreased number of SP T cells could result from the enhanced thymocyte apoptosis.