The Thai Journal of Veterinary Medicine


A red-shanked douc langur (Pygathrix nemaeus nemaeus) is currently enlisted as an endangered primatespecies. This study was undertaken to describe the gross anatomy, histology and ultrastructural morphology of thedouc langur term placenta by light, scanning, and transmission electron microscopy. The primary disc of bidiscoidalplacenta was separated to 4-6 small cotyledonary subdivisions and was attached by an umbilical cord. The chorionfrondosum of placenta was classified as villous, haemomonochorial and deciduate type. The interhaemal area wascomposed of a layer of syncytiotrophoblast that occasionally clustered as the syncytial knot, fetal capillaryendothelium and its basement membrane. The intervillous mineralized fibrinoid mass and syncytial knot wereprominent features in term placenta of the douc langur. The chorion laeve consisted of an avascular layer of amnioticcells, the extravillous cytotrophoblast layer and the endometrial decidual cells layer. The allantoic duct was presentedbetween the umbilical vessels in the umbilical cord. Ultrastructurally, the surfaces of placental chorionic villi werecovered by numerous microvilli. The prominent indentations and entrapped maternal red blood cells were observedat the tip of the terminal villi. The syncytiotrophoblasts contained densely clumps of chromatin within the nucleusand dark-staining vesicles in their cytoplasm whereas the cytotrophoblast had clumps of chromatin distributed at theperiphery of the nucleus. The result of this study is the biological data for further conservation studies of this species.

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