Fig. 5. Ornithine decarboxylase (ODC) siRNA exacerbates DNA oxidative/nitrative stresses, poly(ADP-ribose) polymerase 1 (PARP1) activation and ATP depletion during cisplatin nephrotoxicity. The kidneys in C57BL/6 male mice were harvested 1, 2, or 3 days after cisplatin injection or non-injection (control). The mice were orally supplemented with either spermidine (10 mg/kg body weight) or vehicle twice daily from 24 hours before cisplatin injection up to the time that they were sacrificed. ODC siRNA (siODC) or control siRNA (siControl) was injected at 48 and 24 hours before cisplatin injection (n=5 mice in each group). (A) The expression of ODC protein (left) was confirmed using a western blot analysis with anti-ODC antibody in kidneys after cisplatin injection. Antibodies to β-actin were used as a loading control. The intensities of these protein bands (right) were quantified using the AzureSpot software (Azure Biosystems, Dublin, CA, USA). (B) ODC expression in kidneys of control mice transfected with siODC or siControl, as represented by western blot. Antibodies to β-actin were used as loading control. (C) 8-OHdG concentration in kidneys. (D) 8-Nitroguanine concentration in kidneys. (E) PARP1 activity in kidneys. (F) ATP concentration in kidneys. ^*P<0.05 vs. control, ^#P<0.05 vs. vehicle, ^†P<0.05 vs. siControl.