Histomorphometric and hormonal parameters of rats after gestational, lactational and juvenil exposure to diet with zinc deficiency or supplementation: early and late evaluation

Abstract

The present study aims to investigate whether the exposure to diets with zinc deficiency or supplementation during gestation, lactation and juvenile period alter the histomorphometric parameters of reproductive organs and thyroid and the hormone levels of male offspring evaluated at peripuberdade (early evaluation) and at adulthood (late evaluation). Pregnant Sprague-Dawley rats (n = 10/experimental group) will be exposed to a standard diet (AIN 93G) with normal levels (0.012 mg / g), deficiency (0.005 mg / g) or supplementation (0.18 mg / g) of zinc. Pregnant rats will receive the experimental diets ad libitum from gestational day 10 until postnatal day 21 (PND 21, the end of the lactation period). After weaning, male offspring will be distributed in three groups (20 animals/group) that will receive the same diets received during intrauterine life and lactation until PND 53 (G1: standard diet; G2: diet with zinc deficiency; G3: diet with zinc supplementation). On PND 53, 10 animals/group will be euthanized for an immediate evaluation of histomorphometric parameters of the testes, epididymis, and thyroid and dosage of serum hormones levels. The other animals (10 animals/group) will be kept receiving a standard diet until PND 115 when they will be euthanized for late evaluation of these same parameters. The results obtained in this study will clarify whether the intake of a diet with zinc deficiency or supplementation during important periods of rat development impairs the morphology of reproductive organs and thyroid, as well as alters the hormone levels. Furthermore, this study will investigate whether the possible effects on these parameters are permanent during the adult life of the animal, even after returning from ingestion of diet with standard concentrations of zinc. (AU)