Figure 5.

Autophagy inhibition leads to accumulation of dysfunctional mitochondria and increase of oxidative stress during eccentric contraction. (A and B) Mitochondrial membrane potential as measured by TMRM fluorescence in isolated FDB muscle fibers from atg7^f/f (top) and atg7^−/− (bottom) female mice, (A) pre-exercise and (B) postexercise. Oligomycin (Olm) and the protonophore FCCP were added at the indicated time points. The percentage of depolarized fibers is shown on the bottom of the graphs. Fibers were considered depolarized if TMRM fluorescence decreased by 10% or more of the initial value following the addition of Olm. Each trace represents the TMRM fluorescence of a single fiber. (C) Overall protein carbonylation in exercised atg7^f/f and atg7^−/− muscles. Left panel: A representative immunoblot for carbonylated proteins. Right panel: Densitometric quantification of the carbonylated proteins. Postexercised atg7^−/− mice show higher protein carbonylation than atg7^f/f (n = 5 each genotype, *P < 0.05). (D) Mitochondrial ROS production. Mt-roGFP1 fluorescence was measured in single fibers of atg7^f/f and atg7^−/− (n = 3 each condition, P < 0.05).