Influence of perinatal exposure to insecticide fipronil: late repercussion on reproductive parameters in male rats

Abstract

The exposure to various substances during the hypothalamic sexual differentiation could interfere with the pattern of development of the nervous system of offspring, inducing permanent changes in neuroendocrine control of reproduction. Fipronil, an insecticide widely used on many cultures, has been listed as a potential endocrine disrupter. Studies have shown that this compound can affect the thyroid, reproductive parameters and central nervous system. However, most studies with fipronil evaluated its acute toxicity and a few refers to possible reproductive effects, especially if exposure occurs during pregnancy. Thus, the aim of this study is to evaluate the possible effects resulting from perinatal exposure to fipronil and its possible later repercussions on reproductive parameters in male rats. Pregnant rats will be exposed to three doses of Fipronil (0.03, 0.3, 3 mg/kg) in the last week of pregnancy (gestational days 15-21) and first week of lactation (postnatal days 1-7) by gavage. After birth, the male offspring will be evaluated using the following parameters: determination of body weight, anogenital distance and age of preputial separation and testicular descent. In adulthood, these same animals will be investigated in relation to: weights of reproductive organs, sperm count, sperm morphology and motility, hormone dosage, histopathological analysis of the testis, epididymis, pituitary, hypothalamus, thyroid, sertoli cell count, sexual behavior and sexual preference, fertility test and androgen receptor expression by immunohistochemistry and semiquantitative analysis of androgen receptors in the testis. This study, in addition to providing training opportunities for qualified human resources, can generate important information for the implementation of government policies on public health regularize its use at levels safe for human exposure. (AU)