Reproductive toxicology of adult rats exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in utero and during lactation

Abstract

Dioxin are polychlorinated organic byproducts from various industrial processes and is the most toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) persisting in the environment due to its cumulative nature. The man and other animals are prone to exposure to TCDD, mainly due to the ingestion of contaminated food and critical periods of development especially during intrauterine life and postnatal. It is known that exposure to TCDD promotes male reproductive system disorders, such as reduction of the weights of reproductive organs, delayed onset of sexual maturation, feminization in male offspring, reduced number of spermatids in the testis and fall in serum testosterone. In addition, exposure in utero and during lactation causes oxidative stress in the epididymis, decrease sperm concentration and motility and transit time of spermatozoa. Although many studies on the effects of TCDD on reproductive health, many are controversial and need to be confirmed and elucidated in both experimental animals and humans, especially their effects on reproductive function and fertility in male offspring. This is intended to evaluate the effect of in utero and lactational exposure to TCDD in the male reproductive system of offspring as an adult, with emphasis on epididymal function and sperm quality. For this, pregnant rats are exposed to different doses of TCDD, being made, later, sperm analysis, epididymal histology, immunohistochemistry, quantification of sperm membrane protein SP22 and investigation of fertility after artificial insemination in utero, the male offspring in adulthood. There will also be carried out measurements of the hormones testosterone, FSH and LH, as well as the determination of membrane protein profiles of epididymal sperm and tissue. It is intended that, besides the formation of qualified human resources in Biology and Toxicology of Reproduction, new knowledge is acquired about the toxic effects of TCDD on the male reproductive tract, disseminating the results through publications in international journals and indexed impact, as well as in communications as scientific meetings in the area. (AU)