Superfund Research Program
PCB Effects on Uterine Muscle
Project Leader: Rita Loch-Caruso (University of Michigan)
Grant Number: P42ES004911
Funding Period: 1995 - 2006
The culminating event of a successful pregnancy is the safe delivery of a viable infant. Without a healthy uterus, this process would not be possible. During pregnancy, the uterus provides a nurturing environment for the developing infant. The uterus is also a muscular organ, and the development of strong, repetitive, oscillating contractions of the uterus characterizes normal labor leading to birth of the infant. Precise regulation of uterine contractions is needed to prevent premature labor and to ensure the development of effective labor at the end of gestation. The aim of this research is to understand whether environmental contaminants commonly found in Superfund sites pose a risk to pregnant women and their offspring by altering uterine muscular functions involved in labor. The research currently focuses on polychlorinated biphenyls (PCBs), a family of chlorinated organic chemicals related by their chemical structure. Although now banned from use, these chemicals are prevalent environmental contaminants due to their previous wide-spread use, limited environmental degradation, and bioaccumulation.
Studies with laboratory animals, wildlife, and human populations suggest that PCBs alter the length of gestation and modify labor. This laboratory has found that PCBs exert a myriad of effects on uterine contraction in rats. When PCBs are applied to isolated segments of rat uterus, uterine contractions may be stimulated, inhibited, or unaffected, depending on the structure of the particular PCB present in the organ bath. Because humans are typically exposed to mixtures of PCBs, studies were performed to examine whether PCB mixtures modify uterine contraction. In organ bath experiments, PCB mixtures stimulated rat uterine contractions. These findings may have implications for remediation strategies, providing insight into possible risks to pregnancy from PCB exposure. Additional experiments are examining responses to PCBs in appropriate cellular models. In preliminary experiments, it has been found that PCB mixtures modify cell functions that would be expected to improve muscular contraction, suggesting possible mechanisms for the previously observed PCB stimulation of uterine contraction.