The effect of polychlorinated biphenyls (PCBs) on bovine oviductal contractions and LIF synthesis during estrous cycle, in vitro studies.

Polychlorinated biphenyls (PCBs) are a group of synthetic xenobiotics that have been used in many industrial applications. Currently, PCBs are among the most prominent environmental contaminants. Previously we showed that PCBs impair secretion of prostaglandins (PGs) at the oviduct. PGs are involved in the regulation of oviductal contractions and the synthesis of leukemia inhibitory factors LIF. Since oviductal contractions are crucial for gamete and embryo transport, and LIF is essential for embryo implantation, the direct effect of PCBs on oviductal motor activity and LIF mRNA expression were investigated. Oviductal strips and cells were taken from cows during the estrous cycle and were treated with PCBs at concentrations close to their environmental ranges. All the studied PCBs decreased the force of the contractions of the longitudinal and circular muscles of the isthmus. Additionally, these PCBs decreased the amplitude of the longitudinal muscle of the oviduct. Moreover, PCB-30-OH and PCB-153 increased the mRNA expression of LIF. Since PCBs inhibit the motor function of the oviduct and stimulate the synthesis of LIF, it is possible that PCBs can slow gamete or embryo transport and increase the potential for pathological embryo implantation in the oviduct.