Evaluation of neurodevelopmental effects on rats exposed prenatally to sulfentrazone

Although some studies have pointed to embryo/fetal toxicity at treatment levels that were not maternally toxic, knowledge about the potential toxic effects of the herbicide sulfentrazone is still limited. Since the results of these studies have raised some concern, the present work studied the effects of sulfentrazone maternal exposure on the physical and neurobehavioral endpoints in the development of rat pups. To accomplish that, the effects of the herbicide sulfentrazone (25 and 50mg/kg) were examined at two different developmental stages in rats: during the first 6 days of gestation, or in the organogenesis period (6-15 days). After parturition, pups were tested in a developmental test battery including measures of growth, maturational milestones, and neurobehavioral development. Maternal exposure to the herbicide resulted in significant alterations of the postnatal age at which the developmental milestones of ear and eye opening and testes descent were observed. There was a reduced weight gain rate in pups and their mothers when treated during the gestational period at the highest dose tested. Also, the functional state of the rat pup nervous system at different stages of postnatal development showed some neurodevelopmental delays in righting reflex, negative geotaxis, grip response, and motor coordination-locomotion and rearing (21-90 days of life) in the treated groups. Herbicide genotoxicity was investigated in fresh leukocytes both in mothers and pups using the comet assay: the data did not show any significant genotoxic effect induced by the herbicide. The findings of this study emphasize that sulfentrazone maternal exposure may lead to some neuromuscular and behavioral deficits in nursing pups.