Effects of hexachlorobenzene on embryonic mammalian cells.

Hexachlorobenzene (HCB) is a persistent organic pollutant that has been found to be bioaccumulating in several Arctic regions of the world. The response of embryonic cells to HCB exposure has been evaluated for several different cytotoxic responses, including genotoxic effects. NIH 3T3 (mouse) and WS1 (human) embryonic cells were exposed to HCB at 1 and 10 times the average newborn cord blood concentrations of Alaska Arctic natives. Assays were then performed to determine the subsequent effects of HCB on overall cell number, viability, cell growth fraction and long-term survival, as well as specific biochemical and molecular responses. Exposure of both cell types to HCB results in cell membrane damage, a short-term decrease in cell number, increased DNA strand breaks, and a long-term decrease in colony survival. WS1 cells also undergo cell-cycle arrest and modulations in glutathione concentration after exposure to HCB. In addition, NIH 3T3 cells exhibit an increased number of transformed foci after repeated exposure to HCB. This study demonstrates that relevant environmental concentrations of HCB have significant effects on mammalian embryonic cells in culture.