Fig. 4

Alterations in the mitochondrial ultrastructure of the SV and quantification of the ATP level and MMP in the cochlea. (A) The mitochondria in the control group were normal (arrows), and those in the D-gal-L and D-gal-H groups had a swollen shape and reduced electron density in their matrix (arrowheads). Severely degenerated mitochondria are indicated with double arrows. In the control group, the microvilli in mitochondria of marginal cells were normal (circle); in the D-gal-L group, the microvilli were reduced or shortened and in the D-gal-H group, most microvilli were missing. Moreover, cytolysosomes containing mitochondrial remnants were found (asterisk) in the D-gal-H group. N, nucleus; n = 4 mice per group. Scale bar = 0.5 μm. (B) The ATP level in the cochleae of the mice in the D-gal-L group was significantly lower than that of the control group but significantly higher than that of the D-gal-L group. (C) The MMP in the cochleae of the mice in the D-gal-L group was significantly lower than that of the control group but significantly higher than that of the D-gal-L group. Data are expressed as the mean ± SD of 6 mice per group. **, P < 0.01 vs. the control group; ^, P < 0.05 vs. the D-gal-L group; ^^, P < 0.05 vs. the D-gal-L group