Desenvolvimento embrionário/fetal, placentação e glicosaminoglicanos no aparelho reprodutor feminino e na placenta / Embryonic/fetal development, placentation and glycosaminoglycans in the female reproductive tract and placenta

ABSTRACT

Background: Fetal attachments, placentation and embryonic development have been widely discussed in rodents such as agoutisand cavies, as well as research on glycosaminoglycans (GAGs) in rats and rabbits. Moreover, studies on buffalo, cattle and sheep aredescribed in ruminants, and work has also been reported in sheep with GAGs in placentoma. However, further studies are needed inthis regard, since there are reports of economic losses associated with reproductive failures described for cattle such as changes in thechorion and allantois, and in sheep in which changes between the transition from vitelline to allantois circulation have been discussed.Review In relation to embryonic development, detailed studies have been described in rodents such as rats (12 days old), desertmouse (15 days old) and agoutis at 30 days. Macroscopic structures such as the cephalic region, nose, optic vesicle, cervical curvature, thoracic and pelvic limbs were observed, as well as microscopic structures such as the pituitary, lung, heart, brain cavity, liver,retina, and ossification regions. There are reports of buffalo and cattle studies in ruminants describing early embryonic development.However, the research in the case of sheep is limited, meaning there is only the ultrasound examination, such as gestational diagnosisand morphometric measurement of the embryonic vesicle. Still, studies with umbilical funicular and placental development of sheepwith different gestational ages can be highlighted. Regarding extraembryonic annexes, four important structures which contributeto embryonic maintenance have been reported. These are called the chorion, amnion, allantois and yolk sac, respectively, and areresponsible for originating the placenta, embryonic protection, collecting metabolic waste and early embryonic nutrition. In...