Fig. 8.
Soleus muscle of aging MGsKO mice had compensated mass but slower contraction and lower developed force. A: 3-mo-old and aging control and MGsKO mice showed similar tibial length that was used to normalize the weight of soleus muscle to show an aging-related decrease in soleus muscle mass. While 3-mo-old MGsKO soleus muscle showed significantly lower mass compared with young controls, no further decrease was found in MGsKO soleus muscle during aging. B: twitch contractile time parameters (TPT, T1/2) were elongated in aging control and MGsKO soleus muscles. Twitch (C) and tetanic (D) forces normalized to muscle weight were lower in aging control and MGsKO soleus muscles. Although the aging MGsKO soleus muscles did not show aging-related decrease in mass, their normalized force was lower than that of age-matched control. CSA, cross-sectional area. Values are means ± SE; n = 5 mice each for young control and young MGsKO groups, n = 6 mice for aging control groups, and n = 7 mice for aging MGsKO group. *P < 0.05, **P < 0.01, ***P < 0.001 vs. young controls. #P < 0.05 vs. aging controls in Student's t-test. &P < 0.05, &&&P < 0.001 vs. young MGsKO mice in one-way ANOVA Fisher test.