U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska


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Published in Molecular Reproduction & Development (2013) 80: 466–473. DOI: 10.1002/mrd.22183


The process of placental separation is not completely understood. In domestic animals, especially cattle, it is important that expulsion of the fetal membranes takes place in a timely manner in order to achieve maximal reproductive efficiency. The activity of the matrix-metalloprotease (MMP) family of proteases is known to be reduced in placentomes fromcases of retained placenta. Members of theMMPfamily are known to be activated by the plasminogen activator (PA) family of proteases.We hypothesized that the expression and activity of the PA family increase in the cotyledon and/or caruncle as parturition approaches, with maximal expression and activity at parturition. To test this hypothesis,weperformed reverse-transcriptase quantitative PCR and plasminogen-casein zymography to detect the presence and activity of PA familymembers in the placentome leading up to and during parturition in spontaneous and dexamethasone-induced parturient ewes. The results from our experiments indicated that serine proteases inhibitor E1 (SERPINE1) mRNA abundance in the cotyledon was different between treatment groups (P = 0.0002). In the caruncle, gene expression for plasminogen activator urokinase-type (PLAU) was different (P = 0.0154), and there was a strong trend for differences in SERPINE1 expression (P = 0.0565). These results demonstrate that expression of the PA system in the placentome changes from late pregnancy to parturition, and the presence or activity of these enzymes may occur after fetal expulsion.