Induction of mRNA for chemokines and chemokine receptors by prostaglandin F_2α is dependent upon stage of the porcine corpus luteum and intraluteal progesterone

This study tested the hypotheses that prostaglandin (PG) F _2α increases expression of genes related to recruitment of leukocytes in mature but not early corpus luteum (CL) and that insensitivity to PGF_2α action in early CL is dependent on high intraluteal progesterone (P4) concentrations. Experiment 1 examined early (0.5 h) and late (10 h) in vivo effects of PGF_2α on mature (d 17 of pseudopregnancy) and early (d 9) porcine CL. Real-time PCR was used to measure mRNA for chemokines (IL8, CXCL2, CCL2, CCL8, CCL4, CCL11) and chemokine receptors (CCR1, CCR2, CXCR2, CCR5). Western blotting was used to measure protein expression and phosphorylation of nuclear factor-κB proteins. Treatment with PGF_2α for 10 h increased mRNA for almost all of these genes (all expect CXCL2 and CCL11) in d 17 CL but not d 9 CL. Treatment with PGF_2α also led to greater phosphorylation of nuclear factor-κB-1A protein in d 17 than d 9 CL. Experiment 2 had a 2 X 2 factorial design with d 9 gilts treated or not treated with epostane (3β-hydroxysteroid dehydrogenase inhibitor to suppress intraluteal P4) and treated or not treated with PGF_2α. Treatment with PGF _2α (10 h) or epostane alone did not induce expression of any of these genes in d 9 CL. However, PGF_2α + epostane increased expression of all of these genes except CCL11. In conclusion, PGF _2α increases mRNA for chemokines and chemokine receptors in mature CL with similar PGF_2α effects induced in early CL if intraluteal P4 is suppressed prior to PGF_2α treatment.