Figure 6

Assessment of NADPH redox state and IDH2 and antioxidant activities in the inner ear of young WT and Idh2^−/− male mice. (a–f) IDH2 activities (a), levels of NADPH (b), NADP⁺ (c), and NADPH/total NADP ratios (d), GSR activities (e), and TXNRD2 activities (f) were measured in the mitochondria of inner ear tissues from 5-month-old WT and Idh2^−/− male mice (n = 4). The activities of GSR (g) and TXNRD2 (h) were measured in the cytosol of inner ear tissues from 5-month-old WT and Idh2^−/− male mice (n = 4). (i) The levels of GSH (left), GSSG (middle), and GSH/GSSG ratios (right) were measured in the whole cell lysates of the inner ear tissues from 5-month-old WT and Idh2^−/− male mice (n = 4). (j,k) The activities of mitochondrial (left) and cytosolic (right) SOD (j) and cytosolic catalase (k) were measured in the inner ear tissues from 5-month-old WT and Idh2^−/− male mice (n = 4). Data are shown as means ± SEM. *p < 0.05 vs. WT. Mito = mitochondrial fraction, Cyto = cytosolic fraction, NADPT = total NADP, GSH = reduced glutathione, GSSG = oxidized glutathione, SOD = superoxide dismutase.