COMPARATIVE-ASSESSMENT OF DNA ADDUCT FORMATION, SALMONELLA MUTAGENICITY, AND CHROMOSOME ABERRATION ASSAYS AS SHORT-TERM TESTS FOR DNA-DAMAGE

DNA adduct formation assay (DAFA) was carried out to compare dose resp onses with the Ames test and chromosomal aberration test using aflatox in B-1 (AFB(1)) and benzo[a]pyrene (BaP). In the bacterial mutation te st, AFB(1) and BaP (0-1 mu g/plate) were all positive in TA97a and TA1 00 with dose-related revertants. However, the slopes of the dose-respo nse curves were gradual (slope 0.55-3.73, r =.84-.98). in the chromoso me aberration test, a significant increase in the percentage of chromo somal aberrations was obtained from male ICR mouse spleen cells treate d with AFB(1) and BaP, but a dose-related increase was insensitive (sl ope 0.09-0.23, r.75-.78). The incidence of chromosomally aberrant sple en cells treated with BaP was significantly increased compared with AF B(1). DAFA was performed in vitro with [H-3]-AFB(1) and [(PH)-P-3]BaP. These two carcinogens were able to induce genotoxicity and showed goo d dose-related increases in terms of DNA adduct formation (slope 0.78- 1.28, r = 1.00). Coefficients of variation (CV) for the slope of each dose-response curve were much lower in DAFA in vitro (CV 15.09-18.34%) than those in any other test (CV 19.69-99.33%, Ames test; 18.89-44.58 %, chromosome aberration test). Furthermore, DAFA in vivo was performe d to investigate organotropic DNA adduct formation and persistence in Sprague-Dawley rats ip or orally treated with AFB, and BaP. DNA adduct s were monitored for 48-96 h by enzyme-linked immunosorbent assay (ELI SA) using corresponding monoclonal antibodies, 6A10 and 8E11. DAFA in vivo demonstrated that the liver and kidney might be the probable targ et organs for AFB, with the highest formation and persistence of DNA a dducts and the lung and liver for BaP regardless of the route of admin istration. The results suggest that DAFA in vitro could be useful for detecting genotoxic compounds, and DAFA in vivo should also be conside red as a good alternative method for the screening of organ-specific c hemical carcinogens.