FIG. 2.

Effects of DFP on the oxidative stress response in the MPTP mouse model of PD. (A, B, C) Mean and SEM amounts of oxidative stress markers in the substantia nigra (SN). N=10 per group for all experiments. ⁺Denotes a significant difference versus controls and *denotes a significant difference versus the MPTP condition: (A) For the ratio between reduced glutathione (GSH) and oxidized glutathione (GSSG) (μM/g of protein): ⁺p=0.026; *DFP 300: p=0.002; DFP 200: p=0.04. (B) For malonaldehyde: ⁺p=0.003; DFP 200, DFP 300: *p=0.01. (C) For 8-oxo-deoxyguanosine (8-oxodG): ⁺p=0.02; DFP 200, DFP 300: *p=0.03. DNA: deoxyribonucleic acid. (D) Mitochondrial labile iron pool. Mitochondria isolated from rat brain were loaded with calcein-AM as described in Materials and Methods section and treated with either DFP or DFO at the indicated concentrations for 20 min at 37°C. Fluorescence of calcein (given in arbitrary instrument units) was measured with a spectrofluorimeter (set at zero level with a sample of unlabeled mitochondria) (mean values of n=3 experiments). The size of the arrow denotes the increment in fluorescence intensity attained after addition of either 100 or 300 μM of the permeant chelator DFP over that attained with an equivalent concentration of the impermeant chelator DFO (that reveals iron bound to extramitochondrial calcein) (*p=0.005 and 0.001, respectively). The size of the arrows is a measure of the intramitochondrial labile (=DFP-chelatable) iron pool (in calcein fluorescence units—a.u.—that are 1:1 equivalent 1:1 to labile iron).