Identification of protein patterns in bovine placenta at early‐mid pregnancy – Pilot studies

RATIONALE Placenta is a crucial tissue for an appropriate development of the fetus and the course of pregnancy. Its composition and structure change dynamically along pregnancy but the full pattern of these changes is not fully described in cows yet. The aim of the present study was to detect qualitative and quantitative protein profiles of bovine placenta during early-mid pregnancy at the time of placental formation. METHODS Placental tissues from healthy cows (n = 3) in early pregnancy (3-5 months) were collected at the slaughterhouse. Maternal and fetal parts were manually divided prior to homogenization. Further analysis was done in triplicates on the maternal and fetal parts separately and subjected to one-dimensional (1D) electrophoretic separation, followed by identification of peptide maps by nanospray liquid chromatography/tandem mass spectrometry (nanoLC/MS/MS). Proteins were identified by use of the MASCOT software with the SwissProt database. RESULTS Proteomic analysis showed more than 4000 differentially expressed proteins in maternal and fetal parts of placenta. Each part expressed around 900 proteins, of which ca. 90 were common. The identified proteins were analyzed in accordance to molecular function and their participation in biological processes. CONCLUSIONS The obtained results provide new insight into the knowledge about biochemical characteristics of placenta (new proteins) and serve for further studies on the possible markers of physiological/pathological pregnancy or function of placenta. Moreover, our data can be a good starting point for further studies on the processes underlying the attachment of placenta.