Contribuições ao Estudo Comparativo do Fibrinóide em Placentas Humanas, de Gestações Normais e com Pré-eclâmpsia

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Human placenta is a temporary organ, but indispensable to the fetal and embryonic development of each individual; its main function consists in the fetal-maternal exchanges. Its principal components are the basal and chorionical plates, with the villous tree and the maternal-bood gap interposed between them. In the villous tree, we find the fibrin, acellular material, wich may be of the fibrinous-type, when derived from a maternal clot and of the matrix-type when derived from extravillous trophoblastic cells. The fibrin is found in placentas of normal gestations, but in great quantity in placentas of pre-eclamptic gestations. The purpose of this experiment has been to study, comparatively, the microscopic anatomy of the fibrin and related structures in placentas of normal gestations and in pre-eclamptic gestations. A comparative histological study has been performed in twenty human placentas of which ten placentas were of normal gestation and ten placentas were of pre-eclamptic gestations. Of these, four fragments have been taken from each of the paracentral region, collected from the basal plate up to the chorionical plate, and fixed by immersion in 1/6 molar Ringer-lactate formalin at 4%. Slides wich have been prepared have been submitted to the following colourations: Eosine-hematoxiline, PAS and Mallory for the analysis of clear field microscopy. After a comparative analysis, it has been observed that placentas of pre-eclamptic gestations showed morphological characteristics different from the normal ones, such as: increase of fibrin fibrinous-type and the matrix-type fibrin in quantity and volume, thickening of the trophoblastic basal membrane, increase of sprouts, increase of sinusoid capillaries, characterizing vascular congestion and increase in the surface area of the epithelial plates. We believe that these results are a consequence of the vascular alterations proper to pre-eclampsia, such as blood flow alteration, adaptation of the spiral arterioles, generalized arteriolar spasm, hyperplasia of the muscular layer of the arterioles in the villous trunks, among others.

ASSUNTO(S)

gravidez placenta ciencias biologicas fibrina fibrinóide pré-eclâmpsia

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