Restrição protéica in utero : desenvolvimento sexual e histofisiologia do sistema reprodutivo de ratos machos / In utero protein restrition : sexual development and histophysiology of the rat male reproductive tract

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

26/02/2010

RESUMO

In the past few years the worldwide recognition of the relevance of nutrition as a basis for social and economic development has been growing. In developing countries such as Brazil undernutrition is a socioeconomic problem caused by poor nutrition and low income. The birth of children with low birth weight is considered an important public health problem, with devastating effects on human development, survival and health. Although millions of children have their growth retarded due to poor nutrition, few works relate maternal proteic undernutrition to the development of the reproductive system. Thus, the objective of the present work was to evaluate the impact of in utero proteic undernutrition on morphofunctional endpoints in the male reproductive tract during the following phases of sexual development: prepubertal, peripubertal and adult, as well as on the installation of puberty in the female pups, utilizing the rat as the experimental model. For this, pregnant female rats were obtained and divided into two experimental groups: one treated with standard chow (SC, n=12, 17% protein) and the other treated with hypoproteic chow (HC, n=16, 6% protein) throughout gestation. During the lactation period the two groups received standard chow. On the 20th gestational day 10 rats (SC n=4, HC n=6) were sacrificed and laparotomy was performed to evaluate maternal reproductive performance. The remaining pregnant rats (SC n=8, HC n=10) were left to deliver and nurse the offspring. The proteic restriction provoked reduction in the placental weight, increase in the maternal chow consumption at the beginning of pregnancy and reduction at the end of pregnancy and beginning of lactation. However, this variation in the chow consumption was not sufficient to compensate for the hypoproteic effect on the maternal and fetal organisms, since the maternal weight gain over gestation and the weight of the pups in the different phases of the development were significantly reduced. The anogenital distance increased in the female pups of the HC group suggesting a process of masculinization of the female phenotype. In both sexes the in utero proteic restriction delayed pubertal installation. In the male offspring the proteic restriction caused reduction in the testicular weight at prepuberty and, at adulthood, damage to some of the morphofunctional endpoints of the reproductive system by reducing: the vas deferens weight, number of Sertoli cells, sperm motility, daily sperm production and sperm reserves in the epididymal cauda. Serum testosterone levels were lowered by 27% compared to the SC group. On the other hand, the incidence of sperm cells with morphological abnormalities and retention of the cytoplasmatic droplet increased. It was concluded that the proteic restriction in utero, in these experimental conditions, restricted growth, compromised the sexual development by delaying the beginning of puberty and leaded to damage in adulthood.

ASSUNTO(S)

dieta com restrição de proteinas rato reprodução animal puberdade espermatozóides protein-restricted diet rats animal reproduction puberty spermatozoa

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