Figure 10.

Sigmar1^−/− mice showed reduced grip strength and exercise capacity compared with wild-type (Wt) mice. A: Bar graphs represent summary data showing absolute forelimb grip strength (N) and forelimb grip strength normalized to body weight (force/body weight) in Wt and Sigmar1^−/− mice. B: Parameters derived from exercise tolerance tests showing time to exhaustion (minutes), maximum running distance (m), maximum speed attained (m/minute), and average speed (m/minute) in Wt and Sigmar1^−/− mice. C: Bar graphs represent summary data showing voluntary locomotion as total distance covered during a 30-minute trial in an open field chamber. Dots in the bar graphs represent individual values for each Wt and Sigmar1^−/− mice. D: Bar graphs representing acetylcholine receptor α (AchRα) mRNA expression levels in gastrocnemius (Gastro), quadriceps (Quad), tibialis anterior (TA), soleus (Sol), and extensor digitorum longus (EDL) muscles isolated from 9- to 10-month–old Wt and Sigmar1^−/− mice. E: Left panel: Representative Western blot analysis images showing MuRF1 protein level in Gastro, Quad, TA, Sol, and EDL muscles isolated from Wt and Sigmar1^−/− mice. Desmin was used to verify equal protein loading across the lanes. Right panels: Bar graphs showing the quantification for protein levels of MuRF1 in Gastro, Quad, TA, Sol, and EDL muscles isolated from Wt and Sigmar1^−/− mice. Dots in the bar graphs represent individual values quantified for each Wt and Sigmar1^−/− mice. Data are expressed as percentage change to Wt. P values were determined by unpaired t-test. Data are expressed as means ± SEM (A–E). n = 7 to 9 mice per genotype at the age of 9 to 10 months (B); n = 5 to 6 mice per genotype at the age of 9 to 10 months (C); n = 6 mice per genotype at the age of 9 to 10 months (D); n = 3 mice per genotype at the age of 9 to 10 months (E). ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P < 0.001.