A indicates group mean data ±1 SE for diaphragm calpain activity in sham controls (black) and cecal ligation puncture (CLP) sepsis (red), sham+SS31 (green), and CLP+SS31 (blue) groups. Calpain activity significantly increased with CLP sepsis compared with controls (P < 0.02), and administration of SS31 to septic animals reduced calpain activity to control levels [P < 0.02 for comparison of CLP and CLP+SS31 groups and not significant (NS) for comparison of CLP+SS31 and sham controls]. Calpain activity for sham+SS31 animals was similar to controls (NS). B displays group mean data ±1 SE for diaphragm 20S proteasome activity for sham controls (black) and CLP sepsis (red), sham+SS31 (green), and CLP+SS31 (blue) groups. Proteasome activity was increased in CLP sepsis compared with sham controls (P = 0.013 for this comparison), and SS31 administration to CLP sepsis animals prevented increases in proteasome activity (NS for comparison of CLP+SS31 and sham controls). *Statistical significance; n = 5 mice per group. AMC, amino-4-methylcoumarin.