Morphological aspects of placenta of the Bradypus variegatus Shinz, 1825

Abstract

The morphological aspects of the placenta and fetal membranes were investigated in 03 sloth originated from the forestal zone in the state of Pernambuco, Brazil. These structures were obtained in 03 pregnant females from Universidade Federal de Pernambuco, two of them were frozen and the third placenta was collected by caesarian, and mother and fetus were preserved. After defrost the placenta were fixed in formaldehyde 10,00% water solution. The small fragments were collected in the placenta and umbilical cord from caesarian. These fragments were fixed in 4,00% paraformoldehyde and processed, as usual, for light microscopy; the specimens were embedded in paraplast. HE and Masson stained 5 mm thick sections. The sloth placenta is chorioamniotic, with villous chorion composing the placental lobes, localized in the fundic uterus region. The smooth chorion has relationship with intern face of the uterus. In late gestation the lobes of placenta fused and increase the size in a unique discoid mass, characterizing the placenta discoid. The umbilical cord connect the fetus with placenta, two arteries and one umbilical vein compose it. The histological result suggests a labirinthic and endotheliochorial placenta in these animals. Therefore, the sloth placenta may be classified as labyrinth, endotheliochorial, multiple, discoid (at term) and chorioamniotic.