Dados do Trabalho

Título

DEVELOPMENTAL MILESTONES EVALUATIONS AND BRAIN MEASUREMENTS IN RATS EXPOSED TO THE LARVICIDE PIRIPROXIFEM DURING THE GESTATIONAL PERIOD

Resumo

INTRODUCTION: In 2015, there was an increase in the occurrence of microcephaly in Brazil, which was related to maternal contamination by Zika virus during pregnancy. However, there are inconsistencies between the Zika maternal infections rates in relation to microcephaly cases. Thus, other causes that may be related to the occurrence of this malformation have been studied, including the exposure of pregnant to pesticides. The pyriproxyfen is a pesticide used to control the Aedes aegypti mosquitoes, the vector of Zika virus. This pesticide is structurally similar to retinoic acid, a derived from vitamin A, involved in the control of neurogenesis during embryonic development. OBJETIVE: This study evaluated if prenatal exposure to pyriproxyfen can affect the neonatal development and brain measurements in rats. METHODS: Wistar rat pups were divided into negative control group (offspring of mothers that drink water during pregnancy, CT-); positive control group (offspring of mothers that drink water containing 2 g/L of vitamin A during pregnancy, CT+) and pyriproxyfen group (offspring of mothers that drink water containing 0.002 g/L of Sumilarv during pregnancy, a pesticide that uses pyriproxyfen as the active ingredient, PIR). From the 1st to the 21st postnatal day, the developmental milestones of pups were evaluated. At the 45th day of age, animals were euthanized and measurements of the brain volume, the brain and cerebral hemisphere length, the cerebellar vermis length, the maximum brain and cerebellar width were performed. RESULTS: Neonatal developmental assessments showed that PIR group performed latter the forelimb grasping, but carried out early the negative geotaxis task compared to CT- and CT+ groups. CT+ group exhibited the audio startle response latter than the other groups. However, the eyelids opening and the hindlimb placing response were performed early by the CT+ group. A reduction in the maximum brain width was observed in PIR and CT+ groups when compared to CT- one. CONCLUSION: The changes in neonatal developmental milestones observed in the PIR group were not the same as those seen in the CT+ group, showing that this pesticide does not appear to interfere with retinoic acid signaling during embryogenesis. However, pyriproxyfen affected the acquisition of part of the developmental milestones evaluated and reduced the maximum brain width of the offspring, suggesting that prenatal exposition to this pesticide can produce neurotoxic effects.

Palavras Chave

Teratogenesis; Pyriproxyfen; Microcephaly