Advisor: Mihaela Pavlicev

Master's Defensio - Wednesday, May 22nd 2024, 13:30
SR 5.1, UBB
Djerassiplatz 1, 1030 Vienna

Abstract

Reproductive success is key for the continuity of populations, the persistence of biological systems and their evolution. In eutherians, a functional extra-embryonic tissue and its interaction with maternal tissues contributes significantly to the development of a healthy embryo, and thus the reproductive success. While the placenta and its variability across eutherians is well appreciated, little attention has been paid to extra-placental and maternal tissue involved in the fetal-maternal interface. Deciphering the interaction of these components provides insight into the mechanisms and processes that underpin a healthy pregnancy. While broader comparative work is necessary to gain an understanding of this aspect in pregnancy, the present contribution focuses on the fetal-maternal interface in guinea pig (Cavia porcellus). We investigate the cell composition of the interface at three time points of the long gestation (6.5, 30.5, and 55 days post copulation) and at the non-pregnant stage in diestrus. In doing so, we utilize histological staining methods to generate a gross description on the morphology and cell types present within the reproductive tissue of guinea pigs. Additionally, we compare the findings with newly generated single-cell RNA sequencing data generated by Basanta & Stadtmauer (in prep.). We observed the most significant diversification of the cells at the fetal-maternal interface between the time point of implantation (6.5 dpc) and the mid gestational time point (30.5 dpc). This period comprises crucial processes such as decidualization of the endometrium and the formation of placental structures, shaping the guinea pig utero-placental interface. These include the accessory subplacenta, a structure resembling the villi of the human chorio-allantoic placenta. In the second portion of pregnancy, after the luteo-placental shift in progesterone production, the processes of degeneration set in. These include the eventual loss of the subplacenta and the accumulation of amorphous dead cell masses in the broad junctional zone. This junctional zone separates placental tissue from maternal decidua and exhibits a chaotic appearance characteristic of this species. These findings shed light on the complexity of the process leading to the establishment of the utero-placental interface and its transformation throughout the guinea pig’s pregnancy.