Electron and Scanning Microscopic Observations on the Syncytiotrophoblast Microvillous Membrane Contribution to Preeclampsia in Early Placental Rats

Manar E Selim

doi:10.4172/2155-9864.1000137

Abstract

Pre-eclampsia is a pregnancy-specific syndrome characterized by new-onset hypertension and proteinuria, occurring usually after 20 weeks’ gestation. The current study was carried out on 60 female Wistar rats. Group I: included virgin non-pregnant rats. Group II: included pregnant rats that were received saline solution (0.5 ml/100 g body weight) subcutaneously daily starting from day 7 to day 14 of gestation and served as control group. Group III: included pregnant rats that were treated with bestatin dissolved in saline in a dose of (40.0 μg/ml)/100 g body weight subcutaneously and daily starting from the same day of gestation and for the same duration as mentioned for group II, to make an animal model of preeclampsia. Hence several possible mechanisms of the activation in pre-eclampsia can be considered, all dependent on the syncytiotrophoblast microvillous surface membrane which is the placental surface in contact with maternal blood. Electron microscopic study revealed regions of syncytiotrophoblast in process of degenerative change were found. These regions were more abundant in pre-eclamptic specimens. Increase irregular deeply indented nuclei of the syncytiotrophoblast layer. Regions of syncytiotrophoblast revealed dilated cisterns of rough endoplasmic reticulum. The objectives of this study were to develop an approach to definitively identify and distinguish the syncytiotrophoblast ultrastructural changes to unambiguously determine the relative susceptibility to constitutive and placental oxidative stressinduced preeclampsia.

Highlights

The placenta undergoes growth as well as morphological and functional changes with advancing primate pregnancy to promote fetal development
The syncytiotrophoblast secretes progesterone in addition to human chorionic gonadotropin and human placental lactogen (HPL); hCG prevents degeneration of the corpus luteum
Progesterone serves to maintain the integrity of the uterine lining and, until the syncytiotrophoblast is mature enough to secrete enough progesterone to support pregnancy, it is aided by the corpus luteum graviditatis [2]

Summary

Introduction

The placenta undergoes growth as well as morphological and functional changes with advancing primate pregnancy to promote fetal development. It is a unique tissue in that it is a multi-nucleated, terminally differentiated syncytium that lacks proliferative capacity and instead is maintained by fusion of underlying cytotrophoblast cells [2] It is the outer syncytial layer of the trophoblasts and actively invades the uterine wall, rupturing maternal capillaries and establishing an interface between maternal blood and embryonic extracellular fluid, facilitating passive exchange of material between the mother and the embryo [3]. Preeclampsia is a disease of human pregnancy characterized by a systemic maternal inflammatory response associated with endothelial dysfunction, hypertension, and proteinuria. It has been postulated that the abnormally decreased and intermittent perfusion of the intervillous space of the placenta results in oxidative damage and the release of apoptotic and aponecrotic placental tissue into the maternal circulation [6]. Using an in vitro model of hypoxia/reoxygenation (H/R) that replicates the oxidative stress in placental tissues undergo during preeclampsia, Received January 24, 2013; Accepted March 27, 2013; Published March 31, 2013

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