Patterns of protein glycosylation in bovine placentomes as a function of gestational age and in retained versus non-retained placenta

The formation of placenta at the beginning of pregnancy and its separation at parturition require not only deep remodelling of extracellular matrix, which mainly consists of proteins conjugated with sugar moieties, but also the cooperation with cells from both maternal and foetal parts of placenta. The aim of the study was to compare the patterns of selected conjugated proteins with sugar moieties between pregnant and term placenta as well as between released and retained placenta in cows. Placental samples from healthy pregnant cows (3-5 months of pregnancy) were collected at a slaughterhouse (n = 6), and parturient samples were collected during caesarean section at term and retrospectively divided into retained (n = 6) and released (n = 6). The pattern of selected sugar moieties conjugated with proteins was detected by use of lectin blotting with Phaseolus Vulgaris leucoagglutinin, Maackia Amurensis and Sambucus Nigra (Elderberry). The comparison and analysis of obtained band patterns showed differences between their number, molecular weight and abundance related to the intensity of staining. Samples from 3 to 4 months showed similarities, while at the 5th month, clear differences were visible in all 3 lectins, which were used in this study. Samples from retained/released placenta expressed significant differences in PHA-L and SNA pattern in the foetal part. Obtained results indicate that the development of placenta related to extracellular matrix and accompanying cells from both sides of placenta shows dynamic changes during pregnancy. Moreover, in the case of animals with the retention of foetal membranes the patterns of proteins conjugated with sugar moieties are altered, suggesting that the changes in extracellular matrix metabolism can be involved in the attachment and detachment of the placenta in cows.