Combined effects of exposure to di-n-butyl phthalate and the obesogenic environment on the testicular struture and function of gerbil adult

Abstract

The male reproduction involves complex processes and deregulation in the steroid hormones can alter testicular development and reproductive capacity. Endocrine disruptors (ED) are known to act as xenoestrogens and impair the normal function of hormones. A class of ED are phthalates, plasticizers compounds widely used by industry today. These are responsible for a series of changes in testicular structure and function, but its effects are focused on high dose exposure during pregnancy and lactation in rats. Recent studies on the association between obesity and ED have shown that exposure to ED contribute to the increased metabolic dysfunction and reproductive disorders. Thus, this study aims to assess the combined effects obesogenic environment and exposure to low doses of endocrine disruptor di-n-butyl phthalate (DBP) (5 mg / kg body weight / day) from gestation until sexual maturity, on the testicular structure and function of adult gerbils. For this, we analyzed four experimental groups: 1) control group (C), 2) group treated with di-n-butyl phthalate (F), 3) group subject to the obesogenic environment during pregnancy, lactation until sexual maturity (Ob ) and 4) group subject to the obesogenic environment during pregnancy, lactation until sexual maturity and the concomitant exposure to DBP (ObF). The DBP will be administered in the drinking water of animals. The testicles will be subjected to histopathological evaluations to verify the degree of maturation and tissue damage, based on the Johnsen score. Analysis of the expression of steroid hormone receptors (AR and Er±) and functional marker of Leydig cell, (enzyme 17²-HSD) by "Western Blotting" will be used to examine, indirectly, sensitivity to steroids and steroidogenic capacity of the testis. The latter will also be assessed from plasma levels of testosterone and estrogen. Damage to sperm function will be examined by analysis of sperm motility, testicular daily production and transit time in the epididymis. Such analysis will certainly bring new insights for the interpretation of testicular changes caused by exposure to phthalates and associated with this obesogenic environment.