Free-radical production in TH neurons of the SNc in UCP2 WT/KO mice. A, B, Representative photomicrographs of in situ ROS production assessed by the oxidation of DHE to ethidium by . Left photomicrographs show a representation of double exposure (A) for ethidium (red) and Hoechst nuclear staining (blue) or triple exposure (B) for ethidium, Hoechst nuclear staining, and TH immunofluorescence (green) in UCP2 WT mice. C, D, In UCP2 KO mice (right photomicrographs), representative findings for ethidium and Hoechst nuclear staining (C) with TH immunofluorescence (D). Scale bar: (in C) A-D, 10 μm. E, Quantification of the number of red fluorescent mitochondria within TH cells revealed a significant increase in UCP2 KO mice compared with their WT controls (n = 6, n = 5, respectively). *Significant with respect to WT controls (p < 0.05). Error bars represent SEM.