Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: March 4, 2012
Publication Date: July 1, 2012
Citation: McNeel, A.K., Cushman, R.A., Vallet, J.L. 2012. Expression of PRSS, the plasminogen activator system and its activity in the ovine placentome during stage 2 of parturition [abstract]. Journal of Animal Science. 90 (Supplement 3):471 (Abstract #517). Technical Abstract: The molecular mechanisms responsible for placenta separation are not completely understood. We know placentomes from cases of retained placenta possess limited matrix-metalloprotease (MMP) activity and retained placenta occurs at a greater incidence during induced parturition. The plasminogen activator (PA) system is a family of serine endoproteases capable of activating MMP. Two new serine proteases (PRSS) have been recently documented in multiple species, and in mice appear to be involved in follicular development and ovulation. We hypothesized that 1) the expression of PRSS and PA systems and PA activity increase as parturition approaches with maximal expression and activity during parturition, and 2) that both are reduced during induced parturition. To test these hypotheses, placentomes were collected at 17 and 10 d prior to projected parturition and during spontaneous and dexamethasone-induced parturition in ewes. Placentomes were separated into fetal and maternal tissues manually, snap frozen in liquid nitrogen, and stored at -80° C until protein and RNA extraction. Tissue replicates were homogenized and RNA and protein were extracted. Relative quantification for genes of interest was performed via RT-qPCR on purified RNA using the delta-delta-Ct method with GAPDH serving as the reference gene. Expression data were analyzed with the MIXED procedure of SAS with treatment as a fixed effect. Plasminogen-casein zymography was performed on protein isolates. There were no differences in expression of urokinase-type plasminogen activator (PLAU), SERPINB2, SERPINE1, or PRSS23 (P > 0.05). We were unable to detect expression of plasminogen, tissue-type plasminogen activator, or PRSS35. Plasminogen activator activity in placentomes was not detected using zymography. These data demonstrate that in the ewe, neither the PA nor PRSS systems change during Stage 2 of parturition compared to late gestation or induced parturition.