Abstract: BACKGROUND AND AIM: To explore the combined toxic effects of benzene and formaldehyde on mouse embryos in vitro. MATERIALS AND METHODS： Whole embryo culture system was adopted. According to 3×4 factorial design, 12 groups were set up. The 8.5-day isolated mouse embryos were cocultured for 48 hours in freshly centrifuged serum with different concentrations of benzene and formaldehyde. The growth, development and morphodifferentiation of tissues and organs of mouse embryos were studied. The type of combined toxic effects of benzene and formaldehyde was analyzed by ANOVA and direct-viewing analysis. RESULTS:There were no statistically significant differences in embryonic growth and development among control groups in vitro and in vivo group (P>0.05). Benzene and formaldehyde had obvious toxic effect on growth and development in embryos in a dose-dependent manner every index of growth and development, morphodifferentiantion of tissues and organs demonstrated significant differences compared with the solvent control (P<0.05). With the increasing concentrations of benzene and formaldehyde,the incidence of malformation and death of embryo increased. Structure, arrangement and cell polarity of VYS endodermis cells were influenced. When benzene was combined with formaldehyde, the severity of the toxic effects on the embryo was stronger than the addition of the two agents alone. CONCLUSION:Benzene and formaldehyde could cause synergistic developmental toxicity and teratogenicity to embryo in vitro.

Key words: benzene, formaldehyde, whole embryo culture, embryonic toxicity, combined effects