Intramuscular substrate depletion and fatigability of soleus grafts in rats

Abstract

We investigated the relationship between oxidative capacity, substrate depletion, and fatigability of muscle grafts in situ. Isometric contractile properties and fatigability were measured in stabilized grafts and control muscles from age-matched rats. Intramuscular glycogen and triglyceride concentrations were measured before and after the fatigue protocol. Even though stabilized soleus grafts have a reduced oxidative capacity compared with control soleus muscles, no difference was observed between groups in terms of resistance to fatigue. Glycogen concentrations did not decrease significantly during the fatigue protocol in either group. Compared with control muscles, the triglyceride concentration in the grafts was significantly higher before the fatigue protocol and it decreased significantly more following the fatigue protocol.