Adhesion process ensures the formation of the appropriate connection between mother and foetus during placentation and further placental development, which determines physiological pregnancy course. Extracellular matrix of foetal membranes are a rich source of biologically active proteins, the synthesis of which is regulated by hormones. Depending on the stage of pregnancy, the protein profile of the placenta changes, thanks to which its remodelling is possible. The aim of the study was to evaluate the effect of decorin, as well as selected glycosylation inhibitors on the adhesion of caruncular epithelial cells derived from cows during pregnancy. Placental cells were isolated from healthy, pregnant (2nd and 4th month) cows after slaughter, which allowed for the establishment of 4 primary cell cultures without visible cells of fibroblast morphology. The presence of decorin in cell monolayer and cell lysates was determined by the use of immunocytochemistry and Western blotting, respectively. The viability of cells was evaluated by MTT assay. The adhesion of cells to fibronectin was measured spectrophotometrically. Protein N‐glycosylation and O‐glycosylation have a modulating effect on the adhesion and viability of placental cells during early–mid pregnancy. Decorin and tunicamycin were shown to have anti‐adhesive properties with respect to caruncular cells of the pregnant bovine uterus.

Progesterone (P 4 ) is an endogenous steroid and key hormone during pregnancy in cattle. It is mainly synthesized by corpus luteum, affecting the concentration of this hormone in the peripheral blood, but also by placenta, in particular on days 180-240 of pregnancy (Schuler et al., 2018).The physiological effects of P 4 include, among others, endometrial differentiation, implantation and maturation of mammary epithelium (Spencer et al., 2004).The local production of P 4 may be important in controlling the growth, differentiation and function of cells in the caruncle. However, little is known about how to integrate the synthesis of steroids with their metabolism, reaching an appropriate local and

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The activity of glycosidases is crucial for the function and biological activity of proteins conjugated with sugar moieties, which play an important role in adhesion of cells during attachment and detachment of the foetal membranes. The aim of study was to describe the ability of bovine placental tissues to break down O‐glycosidic bonds in different glycoproteins by the determination of activity of β‐galactosidase, α‐l‐fucosidase, β‐N‐acetyl‐hexosaminidase and sialidase in early–mid‐pregnancy as well as at parturition with released and retained foetal membranes. Moreover, the availability of substrates for these glycosidases in placental homogenates was evaluated. Placental samples were collected from pregnant (2–4 months) cows in slaughterhouse (n = 8) as well as during Caesarean section and divided into released foetal membranes (n = 8) and retained foetal membranes (n = 8). Tissue homogenates were subjected to spectrofluorimetric and spectrophotometric determinations of enzyme activities as well as electrophoretic separations. Enzyme activities expressed changes within examined time with significant (p < .05) differences between pregnancy and physiological parturition in β‐N‐acetyl‐hexosaminidase and α‐l‐fucosidase in foetal part of placenta while in maternal part only in the latter one. Decreasing tendency in enzyme activity was noticed in foetal part of retained samples in comparison with released ones with significant (p < .05) differences in α‐l‐fucosidase activity. The analysis of staining of sugar moieties attached to selected proteins depicted availability of sugar molecules in examined tissues, but their patterns differed between samples. In conclusion, sugar moieties in conjugated proteins express changes in the course of pregnancy which is reflected by the alterations in activities of placental glycosidases.

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