Influence of exposure to benzo(a)pyrene in the juvenile period to peripuberty: immediate repercussions in male rats and multigenerational and transgenerational effects of offspring on reproductive parameters

Abstract

Exposure to Endocrine Disruptors (EDs) during critical windows of development can causes epigenetic alterations, which can appear immediately or long after exposure, even in subsequent generations. Benzo(a)pyrene (BaP) is a persistent organic pollutant, widely distributed in the environment. Studies have shown that BaP accumulates in vital and reproductive organs, including the testis; and may interfere with the steroidogenesis process through interaction with the StAR protein. Our laboratory have demonstrated that the BaP exposure provoked significant changes in spermatogenesis in male rats exposed from juvenile period to peripuberty, and that this compound can act as an ED, presenting a non-monotonic response patterns. However, additional data on the cellular and molecular causes of these changes and their persistence on a transgenerational scale are insufficient. The aim of this study is to evaluate the consequences of paternal exposure to BaP, from juvenile period to peripuberty, on F1 (multigenerational) and F2 (transgenerational) generations, in addition to investigating the mechanisms by which BaP caused reproductive change in parental generation (F0). Wistar male rats (Postnatal Day (PND) 23) will be distributed in two groups: a control group (corn oil + DMSO) and one group exposed to 0.1 µg/kg/day of BaP. The animals will be treated for 31 consecutive days, by oral route. In a first step, the F0 generation will be evaluated on PND 54 for investigate immediate toxicity and PND 120: stress oxidative analysis, gene expression, intratesticular testosterone dosage, DNA methylation, TUNEL and comet assay. In a second step, the possible impacts provoked by parental exposure to BaP on F1 and F2 generation will be investigated, through the following evaluations: sexual development, reproductive parameters, TUNEL assay, comet assay, stress oxidative analysis, intratesticular testosterone dosage, gene expression and DNA methylation. (AU)