Figure 5. Oxidative stress contributes to proteasomal inactivation, accumulation of damaged proteins and cell death in cultured neonatal cardiomyocytes.

Proteasomal activity (A), oxidized protein levels and representative blots (B) and cell death (C) in cultured neonatal cardiomyocytes. Concordance between proteasomal activity, oxidized protein levels and cell death in cultured neonatal cardiomyocytes (D). Cells were stimulated with antimycin A (100 µM, Ant A, gray bars) or H₂O₂ (100 µM, gray bars) or Epoxomicin (1 µM, EPO, gray bars) for 2 hours. Measurements were performed 24 hrs after treatments. Experiments were repeated at least 5 times. Protein expression was normalized by GAPDH. Error bars indicate SEM. Proteasomal activity [F (3, 20) = 30.85, p<0.0001]; oxidized protein levels [F (2, 9) = 21.84, p = 0.0003] and cell death [F (3, 14) = 27.53, p<0.0001]. #, p<0.05 vs. non-treated cells (control). $, p<0.05 vs. antimycin A- and Epoxomicin-treated cells.