In vitro and in vivo 32P-postlabeling analysis of 4-vinyl-1-cyclohexene (butadiene dimer) diepoxide-DNA adducts

4-Vinyl-1-cyclohexene diepoxide (VCD), an industrial chemical, and its parent compound, 4-vinyl-1-cyclohexene (VCH), are potential health hazards, as they destroy oocytes in follicles in rodents. VCD is also a skin carcinogen at the site of application in both female and male mice and rats and after gavage, induces ovarian tumors in mice and forestomach tumors in rats. A 32P-postlabeling assay was developed for the detection and measurement of VCD-DNA adducts. VCD, a direct-acting carcinogen, was reacted with DNA in vitro, as well as through mouse skin painting for 3 days with different doses of VCD. 32P-Labeled adducts were separated by polyethyleneimine (PEI)-cellulose TLC and detected by screen-enhanced autoradiography. Comparable adduct profiles were obtained in vitro and in vivo. At higher doses (36–225 μmol/mouse), adduct levels in vivo showed a linear dose response, while there was no difference between 14 and 36 μmol/mouse. The limit of detection was estimated to be 1–3 adducts in 108 DNA nucleotides. The results show that VCD exposure gives rise to (presumably pre-mutagenic) DNA adducts in vivo and that 32P-postlabeling can be applied to biomonitoring of VCD exposure.