Fig. 5.
Increased sensitivity of cortical mitochondria to oxidative stress in PINK1−/− mice. (A) The reduction of state 3 respiration by complex I after 15 min of exposure to 100 μM H2O2 was more dramatic in mitochondria isolated from the PINK1−/− cortex at 3–4 months than from the control (*, P < 0.05, n = 5). Data are expressed as a percentage of the activity of the same sample measured previously in standard conditions. (B) Effect of 15 min of exposure to 500 μM H2O2 on complex II respiratory capacity of cortical mitochondrial preparation at 3–4 months. (*, P < 0.05, n = 9). Data are expressed as a percentage of the activity of the same sample measured previously in standard conditions. (C) Effect of exposure to a mild heat shock (10 min at 43°C before assay) on complex II respiratory capacity of cortical mitochondria preparation at 3–4 months. Data are normalized to WT activity under standard conditions (*, P < 0.05, n = 6). (D) Measure of the transmembrane potential of isolated mitochondria at 3–4 months after 15 min of exposure to 100 μM H2O2 by the JC-1 assay. (E) Mitochondria swelling assay. Data are fitted as the sum of exponentials. τ1 is given as the time constant of the first and main exponential. No difference between genotype was seen under basal conditions or after 15 min of exposure to 200 μM H2O2 (N.S.: not significant, n = 4).