Expression of C–C motif chemokines and their receptors in bovine placentomes at spontaneous and induced parturition

摘要

In bovine placentomes, the inflammatory response is considered important for the detachment of the fetal membrane from the caruncle after parturition. Glucocorticoids, a trigger of theonset of parturition, facilitate functional maturation of placentomes via prostaglandin (PG) and estrogen production in cattle. This study investigated how exogeneous glucocorticoids, whichexert immunosuppressive effects, affect placental inflammation at parturition. Placentomes were collected immediately after spontaneous or induced parturition. Parturition was conventionallyinduced using PGF2α or dexamethasone or with a combination of triamcinolone acetonide and high-dose betamethasone (TABET treatment). Polymerase chain reaction (PCR) array analysis indicatedthat 9/13 C–C motif chemokine ligands ( ) were upregulated > two-fold in spontaneous parturition, with and being highlyexpressed. The expressions of , C–C motif chemokine receptor 1 ( ), and in caruncles were significantlyhigher in spontaneous parturition than in induced parturition. Although the clinical dose of dexamethasone did not influence the expression of these s and s, TABET treatment increased expression. CCL8, CCR1, CCR2, and CCR5 were localized in the caruncular epithelial cells. CCR2 was also localized inthe epithelial cells of the cotyledonary villi. This study is the first report to reveal the disruption in and expression in bovine placentomes atinduced parturition. Enhanced glucocorticoid exposure for the induction of parturition may upregulate expression in placentomes, but the treatment does not adequatelypromote expression. Additionally, immunohistochemistry suggested that the CCL–CCR system is involved in the functional regulation of maternal and fetal epithelial cellsin placentomes at parturition.