Occupational and in vitro exposure to styrene assessed by unscheduled DNA synthesis in resting human lymphocytes.

Lymphocytes from 38 individuals occupationally exposed to styrene concentrations in workroom air of 1 p.p.m. t0 40 p.p.m. were examined for any genotoxic effects using unscheduled DNA synthesis (UDS) as the indicator of DNA damage. The mean level of N-acetoxy-2-acetylaminofluorene (NA-AAF) induced UDS was significantly increases (p less than 0.001) for the styrene exposed group when compared to the mean level for the unexposed controls. There was no significant effect on u.v.-induced UDS from the in vivo styrene exposure. Lymphocyte cultures exposed in in vitro to styrene concentrations up to 100 micro M have confirmed the UDS data collected on individuals occupationally exposed to styrene. In addition, the in vitro study has also shown that the increased NA-AAF induced UDS resulting from styrene exposure was paralleled by a similar increase in NA-AAF binding to DNA. Taken together these results indicate that styrene exposure does not inhibit DNA repair synthesis, but rather it predisposes lymphocytes to an increased risk for DNA damage induction from subsequent genotoxic exposures.