OBJECTIVE To investigate whether aldo-keto reductases(AKRs)can act as a nitrore-ductase(NR)and bioactivate aristolochic acid Ⅰ(AA-Ⅰ)to produce AA-Ⅰ-DNA adducts.METHODS① Human-induced hepatocytes(hiHeps)and human bladder RT4 cells were used as tool cells and treated with AA-Ⅰ0,0.5,1.0 and 2 μmol·L-1 for 24 h.Cell viability was detected using the CCK-8 method,and the half maximal inhibition concentration(IC50)was calculated using the CCK-8 method and the level of DNA adduct production was calculated.②hiHeps and RT4 cells were treated with AKR inhibitor luteotin(0,5,10 and 25 μmol·L-1)+AA-Ⅰ 0.2 and 1.0 μmol·L-1 for 24 h,respectively,and the levels of DNA adducts were detected by a liquid chromatography-tandem mass spectrometer(LC-MS/MS).③hiHeps cells were incubated with 80 nmol·L-1 small interfering RNAs(si-AKRs)for 48 h and treated with AA-Ⅰ1.0 μmol·L-1 for 24 h.Real-time qualitative PCR(RT-qPCR)method was used to detect the mRNA expression of AKRs gene and LC-MS/MS technology was used to investigate the effect of specific AKR gene knockdown on DNA adduct levels.④500 nmol·L-1 human AKR recombinant proteins AKR1A1 and AA-Ⅰwere incubated in vitro under anaerobic conditions and the formation of AA-Ⅰ-DNA adducts was detected.RESULTS ①The IC50 of AA-Ⅰto hiHeps and RT4 cells was 1.9 and 0.42 μmol·L-1,respec-tively.The level of DNA adduct production of the two cell lines was significantly different(P<0.01).② Luteolin≥5 μmol·L-1 significantly inhibited the production of AA-Ⅰ-DNA adducts in both cells(P<0.05),and there was a concentration-dependent effect in hiHeps cells(P<0.01,R=0.84).③In the AKR family,the knockdown of AKR1A1 gene up to 80%inhibited the generation of AA-Ⅰ-DNA adducts by 30%-40%.④The AA-Ⅰ-DNA adducts were detected in the incubation of recombinant protein AKR1A1 and AA-Ⅰ under anaerobic conditions in vitro,approximately 1 adduct per 107 nucleotides.CONCLU-SION AKR1A1 is involved in AA-Ⅰ bioactivation,providing a reference for elucidation of the carcino-genic mechanism of AA-Ⅰ.