Impact of 5-Azacytidine on placental weight, glycoprotein pattern and proliferating cell nuclear antigen expression in rat placenta

During the placentation process, the expression of various glycoproteins plays an important role in embryonal development. Alterations in DNA methylation caused by 5-azacytidine (5azaC) can disturb normal glycoprotein expression as well as the proliferative ability of trophoblast cells. In order to assess this, a single dose of 5azaC was injected intraperitoneally into pregnant rats during days 1-19 of gestation. Animals were euthanised on day 20 and placental weight, as well as glycoprotein composition, was analysed together with immunohistological assessment of the degree of proliferation of the trophoblast cells. The placental weight was found to be significantly smaller in animals treated by 5azaC during days 4 to 14 of gestation (p<0.01, Student's t-test). The treatment on days 4, 5, and 6 resulted in a lack of labyrinth with the strong proliferative activity of the cells in the basal layer. Expression of glycoproteins with molecular mass smaller than 60kDa was reduced with treatment on day 6. The 5azaC administered from days 7 to 10 completely disturbed the placental structure and the proliferation of trophoblast cells was poor. During these days GP70 exhibited stronger expression in treated animals, contrary to GP40, which was stronger in controls. A natural border between the labyrinth and the basal layer was established on days 11 and 12. The basal layer was dominant with a lower proliferation of trophoblast cells compared with the controls. With the establishment of the labyrinth on day 13, the expression of GP40 was restored. Proliferation of the trophoblast cells from days 13 to 15 was higher compared with the controls. The changes in placental mass and the proliferative ability of trophoblast cells in rat placenta exposed to 5azaC represent more proof of the importance of epigenetics in the regulation of placental development

Novi eksperimentalni dizajn arterijalizovanog venskog režnja na modelu uha kunića

The aim of this study was to test a new experimental design of venous system arterialization on the rabbit ear arterialized venous flap (AVF) model. Total number of 10 'Big Chinchila' rabbits were divided in two experimental groups. On both ears of the five rabbits (Group 1) we have performed our original method of venous system arterialization with microsurgical arterialization of the central artery and vein with the preservation of central and peripheral vascular perfusion; at both ears of five rabbits (Group 2) we have performed AVF according to Byan et al., (1995). Vital AVF surface and necrosis percentage were determined in both experimental groups at day 1 and day 14 and results were compared using Student t-test. The results of our experiment indicate that our new experimental design of the AVF on rabbit ear model has better hemodynamic conditions, improves AVF survival and gives significantly bigger vital flap surface at 14 days after venous system arterialization.U radu je prikazan novi eksperimentalni dizajn arterijalizovanog venskog režnja (AVR) na modelu uha kunića. Ispitivanje je izvršeno na ukupno 10 kunića rase 'velika činčila', koji su podeljeni u dve ogledne grupe. Kod 5 kunića je na oba uha sproveden originalni postupak mikrohirurške arterijalizacije centralne arterije i vene uz očuvanje centralne i ivične vaskularne perfuzije. Na 5 oglednih životinja druge grupe je na oba uha izvršena arterijalizacija venskog sistema uha kunića prema modelu Byan-a i sar. (1995). Vitalna površina AVR određivana je prvog i 14- og dana nakon arterijalizacije venskog režnja. Izračunate su srednje vrednosti vitalne površine AVR-a i procenat nekrotične površine. Poređenje rezultata sprovedenih eksperimentalnih procedura je izvršeno Studentovim t-testom. Analizom različitih eksperimentalnih modela AVR na uhu kunića, kako neodloženih tako i onih kod kojih je radi povećanja vitalne površine primenjena metoda odlaganja režnja, utvrđeno je da su dosadašnji modeli neodloženih AVR, potencijalno hemodinamski nepovoljni. Rezultati našeg istraživanja su ukazali da se novim ekperimentalnim dizajnom postiže statistički veoma značajno smanjenje procenta nekrotične površine AVR i povećanje vitalne površine režnja