engleski

5-azacytidine changes placental glycoprotein expression in pre and post gastrulating stages of rat development

5-azacytidine (5azaC), a demethylating agent, precludes methylation causing a change in gene expression resulting in congenital malformations. During placentation, formation of ectoplacental cone at day 8 of gestation, and onset of early placental function at day 11, are considered to be crucial for normal fetal development We investigated the influence of 5azaC on the expression of different placental glycoproteins in pre and post gastrulating stages of rat development. Single dose of 5-azacytidine was injected i.p. to pregnant rats on days 8 and 11 of gestation. Animals were sacrificed on the day 20. Placentas were analyzed for glycoprotein composition by Western blotting using lectins PHA-E and UEA-I. Histological analysis and detection of PCNA expression was done. The 5azaC treatment at day 8 completely upset the placental structure and clearly visible border between labyrinth and basal layer was lost. PCNA signal was detected only in few trophoblastic cells. Lectins UEA-I and PHA-E detected glycoprotein GP70 only in the experimental sample. Treatment at day 11 resulted in reestablishment of natural border between those two layers although labyrinth was significantly reduced. More trophoblastic cells were positive for intranuclear PCNA signal but fewer than in controls. GP70 exhibited higher expression in the treated animals, to the contrary of GP40 with higher expression in controls. The observed deviations from normal glycosylation pattern undoubtedly indicate the crucial role of DNA methylation in expression of glycoproteins prerequisite for normal placentation.

placenta; 5-azacytidine; DNA methylation; rat; glycoproteins; PCNA

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