Efeito do fotoperíodo no disco placentário e o impacto sobre o fígado da prole

Abstract

The present study aimed to evaluate the possible effects of the interference photoperiodic on the morphology of the rat placenta and fetal liver histogenesis. Used 40 albino rats, which were divided into four groups. Group I - rats maintained in light / dark cycle of 12/12 hours for 60 days (control) and then mated, Group II - rats maintained in the dark for 60 days and then mated, Group III - rats maintained in light constant for 60 days and then mated, and Group IV - rats maintained in constant illumination for 60 days and then mated and treated with melatonin. The absence of light was obtained using a room of approximately 3m ², totally fenced to not allow light to enter. The light stimulus was around 400 lux. Melatonin was administered in water at a dose of 400 mg of melatonin in 1 ml of absolute ethanol. The results showed vacuolization of trofospongio in Group II, most layer of the vascular labyrinth trophoblast giant cells and well developed, with large nuclei assuming a character in the hypertrophic group III. The morphological characteristic of the group IV was similar to group I. The histochemical analysis revealed no alterations in the collagen and elastic fibers, reticular and acidic glycosaminoglycans (GAGs). Statistical analysis of the placentas of animals in group III differed significantly from the other groups in the area of the hard placental syncytial trophoblast and in maternal and fetal vasculature in the labyrinth and the number of trophoblast giant cells. In trofospongio layer, the trophoblast cells and syncytial trophoblast did not differ between groups. There were histological and histochemical changes in the livers of newborns, but the number of Kupffer cells was higher in group II compared with group I and group III. In conclusion, The Absence illumination mimics a close to birth as a result of degeneration of trofospongio while the constant light promotes morphological and morphometric changes in the placenta of rats that did not affect the hepatic histogenesis in newborns.