Membranas embrionárias e fetais de equinos sob análise de microscopia eletrônica de transmissão

Abstract

To develop this research, 16 pregnant uteri were used, of which 16 placentas were obtained divided into groups of different stages of development. The material was collected from adult, mixed breed mares up to 100 days of gestation. The membranes were intended for ultra-structural analysis and the results obtained under transmission electron microscopy (MET) were similar to those found by ASSIS-NETO (2005), in bovine membranes, and ITURRIZAGA (2005), in llamas. The fetal membranes did not show relevant structural differences in the different periods studied. The chorion showed columnar epithelium; mesenchymal tissue rich in collagen fibers, the trophoblastic cells being uni, binucleated and rarely trinucleated. A large number of mitochondria were present mainly at the apex of cells. The allantoic presented a simple columnar epithelium with globular nuclei and a large concentration of mitochondria at the cell apex, in the cell base there was a large amount of rough endoplasmic reticulum. The amnion showed a simple, squamous epithelium and at the cellular apex there was a large amount of electrondense granules covered by a rounded halo. The yolk sac epithelium varied from globose to columnar, with uni or binucleate cells in a single layer, with a large amount of rough endoplasmic reticulum, uniformly distributed. Between the endodermal cells, intercellular spaces were found. So far, it is concluded that the mare's placenta is choroidal alloid, epithelial, diffuse, non-deciduous and villous, with corium cells and a yolk sac with characteristics of protein secretion, while amnion presented secretion vesicles, but with less amount of rough endoplasmic reticulum.