Figure 2.
Antioxidants and NOS inhibition reestablished mitochondrial respiration and decreased protein 3-nitrotyrosine levels in mitochondrial proteins from SOD1G93A astrocytes. A, Representative oxygen consumption curves by mitochondria isolated from cultured cerebral cortex astrocytes prepared from non-Tg or transgenic SOD1WT or SOD1G93A rat neonates treated as indicated. Mitochondrial respiration was evaluated as indicated in Figure 1. DMPO (75 mm, 48 h), Mito-Q (10 nm, 24 h), or l-NAME (5 mm, 24 h) were added to the culture medium of SOD1G93A before mitochondrial isolation. Numbers under the traces indicate the absolute values of state-3 and -4 respiration in micromolar O2 per minute. B, Calculated respiratory control ratio for complex I and II of astrocyte mitochondria from the indicated groups. Data are mean ± SEM from four independent experiments. *p < 0.05, significantly different from non-Tg control. C, Protein 3-nitrotyrosine immunoblotting of mitochondrial proteins from the same samples used to measure oxygen consumption in A. Thirty micrograms of mitochondrial protein were seeded per lane in 13% acrylamide gel. Numbers on the left indicate molecular weights, and numbers on the bottom indicate the mean optical density for each lane. This is a representative blot from three independent experiments.