Modulação da expressão gênica caruncular pelo embrião bovino durante a placentação: Influência sobre fatores angiogênicos e vasoativos

Abstract

In cattle, reproductive loss occurs mainly embryonic period (0-42 days), and one of the major cause of this issue are failures in synchronization of maternal and embryonic communication. The conceptus (embryo and extraembryonic membranes) plays a key role in controlling intrauterine environment, leading to the release of paracrine factors for gestational signaling and modulating the expression of genes in maternal endometrium, leading up to implantation and subsequent early placental development. Despite of in vitro production of embryos proves to be a useful tool in increasing productivity of cattle, this method still has gaps in successful of reproductive efficiency. This study aimed to analyze the expression of genes involved with placental vascular function in gravid and non-gravid uterine horns of primiparous cows submitted to artificial insemination (AI) and in vitro fertilization (IVF), in order to identify the regulatory role of embryo on endometrial gene expression and the influence of in vitro embryonic manipulation on this mechanism. In this study, caruncular samples of the gravid horn were collected after the separation of fetal cotyledons, occurring on days 30 (n = 3), 35 (n = 8) and 40 (n = 3) AI and 35 (n = 3) and 40 (n = 3) days IVF. Caruncles of contralateral uterine horns were collected concomitantly. All tissues were frozen in liquid nitrogen and stored at - 80°C until RNA extraction. Four genes (eNOS, GUCY1B3, EDNRB, ANGPT2) involved with placental vascular function were chosen for this study. All samples were processed by Quantitative Real Time PCR (qPCR), at where the analysis of results showed a significant increase (p<0.05) in AI gravid horns between 30 to 35 days for both EDNRB and ANGPT2 genes, while GUCY1B3 was upregulated on gravid horns only at 30 days AI. Expression levels of eNOS did not changed in AI uterine tissues. Late transcription response occurred at 40 days IVF on gravid horns for eNOS, EDNRB and ANGPT2, and no significant alterations (p <0.05) was observed for GUCY1B3. Considering the observed aspects, we conclude that the differential expression of genes on gravid horns has a direct relation with the presence of embryo, being these genes themselves liable to modifications in transcriptional pattern due to adversities imposed by manipulation and culture of in vitro embryos.