The in vitro induction of sister chromatid exchanges and chromosome aberrations in human lymphocytes by styrene derivatives

Three structural analogues of styrene, vinyltoluene (40% para-,60% meta -isomers), 4-methoxy-trans-ß-chlorostyreneand trans-ß-nitrostyrene, were tested for their potentialto induce chromosome aberrations and sister chromatid exchange(SCE) in phytohaemag-glutinin-stimulated human lymphocytes culturedfor 48 h (aberration analysis) or 72 h (SCE analysis). The treatmentswere carried out 24 h (aberrations) or 48 h (SCEs) before harvest.The toxicity of vinyltoluene to cultured lymphocytes was similarto that of styrene while 4-methoxy-ß-chlorostyrenewas about 10 times and ß-nitrostyrene about 100 timesmore toxic than styrene. A dose-dependent increase of SCEs andchromosome aberrations was observed in cells treated with vinyltoluene(0.33–4.00 mM) or with 4-methoxy-ß-chlorostyrene(0.5–1.00 mM). No effect could be seen in cultures treatedwith ß-nitrostyrene (0.004–0.044 mM). The resultssuggest that, like styrene, vinyltoluene and 4-methoxy-ß-chlorostyrenealso are converted in vitro to reactive metabolites, presumablyepoxides.