Cultured porcine endothelial cells were used to determine the effects of several congeners of
polychlorinated biphenyls (
PCBs) on cell viability and changes induced by these congeners on levels of intracellular
calcium and
reactive oxygen species (ROS). Cultured endothelial cells were prepared as a single
suspension and run on flow cytometry. Cell viability, intracellular
calcium, and ROS concentrations were simultaneously determined by using
propidium iodide,
Fluo-3, and dihydrorodamine, respectively. The congeners tested included two coplanar tetrachlorinated congeners that have no ortho chlorines,
PCBs 77 and 80, a tri-chloro congener which does not have any ortho
chlorine, PCB 39, a di-ortho, tetrachlorinated congener,
PCB 52, and a mono-ortho congener, PCB 9. PCB 9 was cytotoxic at 5 μM within 5 min of exposure, and the toxicity increased with time and concentration. None of the other congeners showed consistent cytotoxicity. The cytotoxicity was roughly correlated with elevations in cellular ROS levels, but not with changes in intracellular
calcium. To the best of our knowledge, toxicity of lower chlorinated, more volatile congeners such as PCB 9 has not been previously studied. These observations may be taken to explain the elevated risk of
cardiovascular disease previously reported among residents living near to hazardous waste sites containing
PCBs.