Die Subplacenta hystricognather Nager als In-vivo-Modell für die Trophoblastinvasion beim Menschen
The aim of this pilot study is to test caviomorph placentation for its suitability as in-vivo-model for trophoblast invasion. The placentas of caviomorph rodents are characterized by the presence of a special organ,the subplacenta. The subplacenta is interposed between chorioallantoic placenta and uterine wall. Because of histological reasons, we assumed that the subplacenta is the source of throphoblast invasion and therefore an analogue to the cell columns in the human placenta. To test this assumption, we have applied the in-vivo proliferation marker BrdU (bromo-desoxy-uridine), as a thymidine analogue in guinea pig and degu pregnancy. 1-15 days later the placentas were studied immunohistochemically. We found out that following intraperitoneal injection into the mother we detected plenty BrdU-immunoreactivities in maternal cells in the uterine wall, but only little reactivitiy in trophoblast cells. The subplacenta was completely negative. By contrast strong Mib1 immunoreactivities suggested intense proliferation of cytothrophoblast in the subplacenta. The most logical explanation for this discrepancy was, that BrdU did not sufficiently pass the placental barrier. We therefore changed the procedure and injected Brdu fetally in the amnionic cavity. With this method, the subplacental cytotrophoblast was heavily stained, as expected and maternal cells were only rarely positive. As it is very difficult to aim the amnionic cavity, we finally came to the conclusion, that both ways the intraperitoneal and the intraamnial injection lead to better ways of positive immunreaction. Still the application is not easy and therefore it is not always possible to mark the throphoblast cells in the subplacenta. BrdU is stably incorporated into the nuclear DNA. Because of that, it persists in the cells after they have left the cell cycle. And it remains detectable when the cells invade maternal tissues. Accordingly, the days after application, we found marked trophoblast cells deep in the invasive pathway. Our data are as follows: 1 day after application of Brdu the marked trophoblast cells had invaded at least 150 micrometers up to 350 micrometers from the subplacenta. 6 days after application of Brdu, the cells had invaded as far as 2000 micrometers from the subplacenta into the myometrium.The data suggest that the subplacenta in fact is an analogue to the cell columns in human. Caviomorph placentas seem to be suitable in-vivo-models for study of throphoblast invasion.
info:eu-repo/classification/ddc/610, trophoblast, BrdU, Trächtigkeit, Medizin, Trophoblastinvasion, Caviomorphe Nagetiere, in- vivo, Invasionsweg, Geschwindigkeit der Zellmigration, caviomorph rodents, in vivo, invasive pathway, speed of cellmigration
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