IN-VITRO ASSESSMENT OF INDIVIDUAL AND INTERACTIVE EFFECTS OF AROMATIC-HYDROCARBONS ON EMBRYONIC-DEVELOPMENT OF THE RAT

There have been reports of disruption of embryonic development followi ng exposure of pregnant women to aromatic hydrocarbons, In the present study, the embryotoxicity of toluene, xylene, benzene, styrene, and i ts metabolite, styrene oxide, was evaluated using the in vitro culture of postimplantation rat embryos. Possible interactions between toluen e, xylene, and benzene were also studied using mixtures of these solve nts. The results of the study showed that toluene, xylene, benzene, an d styrene all have a concentration-dependent embryotoxic effect on the developing rat embryo in vitro. Styrene was embryotoxic at a lower co ncentration (1.00 mu mol/mL) than benzene (1.56 mu mol/mL), toluene (2 .25 mu mol/mL), or xylene (1.89 mu mol/mL). The metabolite of styrene, styrene oxide, was embryotoxic at a concentration (0.038 mu mol/mL). more than 20 times less than the parent compound. There was no evidenc e of a synergistic interaction between toluene, xylene, and benzene in causing embryotoxicity; the solvents interacted in an additive manner . The embryos were exposed to the solvents for 40 h of the organogenic period. When the levels of solvents found to be embryotoxic in the pr esent study are compared to blood levels in the human following indust rial exposure or solvent abuse, it appears unlikely that the threshold blood levels for embryotoxicity would be exceeded in the workplace. H owever, the possibility that exposure to solvents earlier or later or throughout the entire organogenic period might result in a different c onclusion cannot be excluded.