Total DNA from colonic crypts was isolated 24, 48, and 72 hrs after AOM treatment from WT and Apex1+/- mice and analyzed for mtDNA damage, mtDNA abundance, and nDNA damage by QPCR. (A) Frequency of mtDNA lesions in WT mice. (B) Frequency of mtDNA lesions in Apex1+/- mice. C) Relative mtDNA abundance in WT. (D) Relative mtDNA abundance in Apex1+/- mice. (E) Frequency of nDNA lesions in WT mice. (F) Frequency of nDNA lesions in Apex1+/- mice. Results are expressed as mean ± SEM values for 3 QPCRs performed in triplicate. (G) Relative APE1 mRNA levels in WT mice 48 hours after AOM treatment. (H) Relative APE1 mRNA levels in Apex1+/- mice 48 hours after AOM treatment. WT and Apex1+/- mice: N=8 for Saline treated mice; N=9 mice 24 hr AOM treatment; N=9 mice 48 hr AOM treatment; N=8 mice, 72 hr AOM treatment. Asterisks (*) denote statistical significance (One-way ANOVA, *P<0.05, **P<0.01).