Toxic effects of Baccharis trimera on pregnant rats and their conceptuses.

Abstract

Studies were conducted to evaluate the effects of the hydroethanolic extract of Baccharis trimera (HEBT) in pregnant rats when administered during the period of organogenesis and the entire pregnancy and the occurrence of malformations and/or variations in their litters. A total of 35 nulliparous outbred female Wistar rats were tested for pregnancy and the B. trimera extract was administered to the pregnant rats and the clinical signs of toxicity were recorded. Ovariohysterectomies were performed, ovaries were weighed and the number of corpora lutea was counted. The uterus was weighed with the conceptuses and, after the conceptuses were removed, the uterus was weighed again to determine the corrected weight gain. The number of live and dead fetuses, implantation sites and reabsorptions were counted. All fetuses and respective placentas were individually weighed, measured and systematically inspected for external structural anomalies. The implantation rate, reabsorption rate, pre-implantation loss, post-implantation loss and placental index were determined. The rats were then euthanized and their kidneys and liver were removed and weighed. Results showed that HEBT, when administered at daily oral doses of 8.4 mg/kg, was toxic to the kidney and liver in rats and the severity of changes was directly associated with exposure time to the toxic agent. The extract also interfered with blastocyst implantation. The administration of the extract throughout pregnancy increased the incidence of visceral malformations and skeletal variations and caused a decrease in fetal weight, size and ossification. However, the fetal abnormalities might not have been due to the direct effect of the extract, but rather to the maternal toxicity induced by it.