Involvement of prostaglandin F2α in the adverse effect of PCB 77 on the force of contractions of bovine myometrium

Polychlorinated biphenyls (PCBs) stimulate in vitro both the force of myometrial contractions and endometrial secretion of PGF2 alpha in cattle. Therefore, the goal of this study was to investigate the participation of PGF2 alpha in the effect of PCBs on uterine contractility. For this aim, the myometrial strips were incubated (48 h) with PCB 77 at the dose of 1, 10 and 100 ng/ml (i.e., 0.0034, 0.034 and 0.34 nmol/ml) separately or jointly with indomethacin (INDO, 10(-4) M), which blocks the PGF2 alpha synthesis. Next, the force of myrometrial strips contractions was measured. Further, the influence of PCB 77 (0.1, 1 and 10 ng/ml) on the PGF2 alpha secretion from myometrial cells after 6,24, and 48 h and PCB 77 (1 and 10 ng/ml) on the mRNA expression of cyclooxygenase 2 (COX-2) and PGF2 alpha synthase (PGFS) in myometrial cells after 6 and 24 h, was investigated. The increase (P < 0.05-0.001) of the contractions force of myometrial strips evoked by each dose of PCB 77, was markedly reduced (P < 0.05-001) by INDO. There was an increase (P < 0.05-0.001) of both PGF2 alpha secretion after all studied periods of cell incubation and mRNA expression for COX-2 and PGFS after 6 h treatment of myometrial cells with PCB 77. It can be concluded that myometrial synthesis of PGF2 alpha and its further secretion is a part of the mechanism by means of which PCB 77 may affect the force of myometrial contractions in cattle. (C) 2009 Elsevier Ireland Ltd. All rights reserved.