Rapid Accumulation of Polymorphonuclear Neutrophils in the Corpus luteum during Prostaglandin F2α-Induced Luteolysis in the Cow

Abstract

Prostaglandin F2α (PGF2α) induces luteolysis within a few days in cows, and immune cells increase in number in the regressing corpus luteum (CL), implying that luteolysis is an inflammatory-like immune response. We investigated the rapid change in polymorphonuclear neutrophil (PMN) numbers in response to PGF2α administration as the first cells recruited to inflammatory sites, together with mRNA of interleukin-8 (IL-8: neutrophil chemoattractant) and P-selectin (leukocyte adhesion molecule) in the bovine CL. CLs were collected by ovariectomy at various times after PGF2α injection. The number of PMNs was increased at 5 min after PGF2α administration, whereas IL-8 and P-selectin mRNA increased at 30 min and 2 h, respectively. PGF2α directly stimulated P-selectin protein expression at 5–30 min in luteal endothelial cells (LECs). Moreover, PGF2α enhanced PMN adhesion to LECs, and this enhancement by PGF2α was inhibited by anti-P-selectin antibody, suggesting that P-selectin expression by PGF2α is crucial in PMN migration. In conclusion, PGF2α rapidly induces the accumulation of PMNs into the bovine CL at 5 min and enhances PMN adhesion via P-selectin expression in LECs. It is suggested that luteolytic cascade by PGF2α may involve an acute inflammatory-like response due to rapidly infiltrated PMNs.

Toll-like receptor 2 and 4 expression in the bovine corpus luteum during the different stages of the estrous cycle

“…Both pathways stimulate the secretion of pro-inflammatory cytokines. Similarly, proinflammatory gene expression increases during regression of the CL (Atli et al, 2012;Shirasuna et al, 2012). Therefore, an increase in both TLR2 and TLR4 mRNA and protein levels in rCL in the present study may indicate roles of TLR signaling in the proinflammatory cytokine-mediated regressing mechanism in bovine CL.…”

“…For example, despite the fact that the PGF 2α receptor was only detected in large luteal cells where the first luteolytic signal was expected to start (Mamluk et al, 1998), our previous studies have shown that luteolytic induction occurs in endothelial cells earlier than in luteal cells (Atli et al, 2011;Atli et al, 2012). Although the role of immune cells in the CL was previously thought to be in phagocytosis following luteolysis (reviewed by Pate and Landis Keyes, 2001), the immune cell population and chemokines in the CL are affected during functional luteolysis in the early response to PGF 2α (Shirasuna et al, 2012). Moreover, immune system roles were demonstrated in the dCL in a previous study (Poole and Pate 2012).…”

Dynamics of Circulating Progesterone Concentrations Before and During Luteolysis: A Comparison Between Cattle and Horses1

“…During the past decade, treatment with a PGF analog has become a model for study of the control of progesterone concentration and luteal blood flow during luteolysis in cattle [63,[66][67][68]. For example, the model has been used to demonstrate that polymorphonuclear neutrophils accumulate in the corpus luteum within 5 min after treatment [66] and that nitric oxide is produced in the corpus luteum as a function of PGF [68].…”

“…For example, the model has been used to demonstrate that polymorphonuclear neutrophils accumulate in the corpus luteum within 5 min after treatment [66] and that nitric oxide is produced in the corpus luteum as a function of PGF [68]. However, examination of the published progesterone profiles [66,68] indicates to us that the model was associated with a nonphysiological increase in progesterone. Hypotheses were tested during the nonphysiological progesterone increase and related by interpretation to spontaneous physiological mechanisms.…”

Bovine P-selectin mediates leukocyte adhesion and is highly polymorphic in dairy breeds

“…Both SELP and SELL are significantly upregulated in endometrial cells stimulated with the bacterial product lipopolysaccharide (LPS) (Oguejiofor et al, 2015). SELP is also crucial for the migration of PMN into the bovine corpus luteum during luteolysis (Shirasuna et al, 2012). Persistent corpora lutea are commonly present in cows with uterine infection (Opsomer et al, 2000).…”