Histological and histochemical evaluation of normotensive and preeclamptic placentas

Aim: In this study, we aimed to investigate the histopathology of normotensive and preeclamptic placentas and the localization of alkaline phosphatase activity. Material and methods:In our study, 10 normotensive and 10 preeclamptic, totally 20 placentas were obtained. 1x1x1 cm3 tissues were dissected and fixed in 10% neutral formalin.4 µm paraffin sections were stained with Hematoxylin-Eosin, Masson trichrome and PAS for histopathological examination. Remaining sections were taken to positive-charged slides and incubated at room temperature for 1 hour. Sections were then stained via Gomori's method and micro-graphed under light microscope. Results: Placenta sections of the control group were histologically regular in structure and their trophoblast basement membranes were normal in thickness. In terms of enzymatic activity of alkaline phosphatase: syncytiotrophoblasts showed strong positive reaction in their inner and outer membranes, but no enzymatic activity was observed in cytotrophoblasts, villous stroma and maternal decidua. In capillaries of terminal villi of preeclampsia group placentas; in addition to dilatation and proliferation, there were an increase in number of syncytial bridges and nodes. Vasculosyncytial and trophoblast basement membranes were significantly thickened. Alkaline phosphatase activity was decreased in inner and outer membranes of syncytiotrophoblasts but wasn't observed in villous stroma and maternal decidua. Conclusion:In placentas of preeclampsia group; a significant increase was observed in syncytial nodes and bridges, perivillous fibrin accumulation and trophoblast basement membrane thickness. Although positive enzymatic activity of alkaline phosphatase was seen very strong in normotensive group placentas, it remained weak in the preeclamptic group. Keywords: Placenta, Preeclampsia, Alkaline phosphatase, Light microscope.