Physiological parturition is characterized by sterile, inflammatory-like processes. During parturition, the placenta expresses various proinflammatory mediators, such as chemokines and IL-17. Nevertheless, inflammatory processes present in the parturient mare are poorly characterized. The aim of this study was to investigate the expression of selected chemokines and IL-17 in the allantochorion and the endometrium of mares that retained fetal membranes (RFM) and expelled them physiologically. We hypothesized that the expression of these mediators may be altered in the placenta of mares with RFM and result in RFM occurrence. Differences in mRNA expression in the placenta of investigated groups of mares were detected for CCL2, CCL3, CCL4, CCL8, CXCL1, CXCL8, CXCL10, CX3CL1 and IL-17. There were no differences in mRNA expression of CCL5 and CXCL6. Gene ontology network analysis showed enrichment in genes related to leukocyte migration, cell chemotaxis and response to chemokine in tissues of RFM mares. Analysis of association network suggested denotations between CXCL6, CXCL8, CXCL1, CCL5, CCL4, CX3CL1 and CXCL10. Moreover, possible inhibition of CXCL10 by IL-17A and prostaglandin peroxide synthase 2 (PTGS2) by CXCL1 was detected. Our results suggest that, based on differences in chemokines and IL-17 expression, recruited subsets of leukocytes might differ between the analyzed groups of mares, which in turn may impair the separation of fetal membranes in the group of RFM mares. In addition, the results of the expression analysis suggest that macrophages might be one of the most abundant cells infiltrating the equine placenta during the expulsion of fetal membranes. Furthermore, we suspect that the synthesis of PTGS2 might be inhibited in mares with RFM.

中文翻译：

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母马胎盘生理性脱离和胎膜保留过程中促炎介质的表达谱

生理性分娩的特点是无菌的、炎症样的过程。在分娩过程中，胎盘表达各种促炎介质，如趋化因子和 IL-17。然而，分娩母马中存在的炎症过程的特征很差。本研究的目的是研究选定的趋化因子和 IL-17 在保留胎膜 (RFM) 并在生理上将其排出的母马的尿囊绒毛膜和子宫内膜中的表达。我们假设这些介质的表达可能在患有 RFM 的母马的胎盘中发生改变并导致 RFM 的发生。在所研究的母马组的胎盘中检测到 CCL2、CCL3、CCL4、CCL8、CXCL1、CXCL8、CXCL10、CX3CL1 和 IL-17 的 mRNA 表达差异。CCL5和CXCL6的mRNA表达没有差异。基因本体网络分析显示 RFM 母马组织中与白细胞迁移、细胞趋化性和趋化因子反应相关的基因富集。CXCL6、CXCL8、CXCL1、CCL5、CCL4、CX3CL1 和 CXCL10 之间的关联网络分析表明。此外，检测到 IL-17A 可能抑制 CXCL10 和 CXCL1 对前列腺素过氧化物合酶 2 (PTGS2) 的抑制。我们的结果表明，基于趋化因子和 IL-17 表达的差异，所分析的母马组之间募集的白细胞亚群可能不同，这反过来可能会损害 RFM 母马组中胎膜的分离。此外，表达分析的结果表明，巨噬细胞可能是在胎膜排出过程中渗入马胎盘的最丰富的细胞之一。此外，