Figure 2. PPARδ activation increases mitochondrial activity and myostatin inhibition increases muscle fiber size in ob/ob mice.

Male mice were treated for 6 weeks with either vehicle (veh, open bars), PPARδ agonist GW501516 (grey bars), myostatin antibody PF-879 (hatched bars), or GW501516 in combination with PF-879 (black bars). Representative cross-sectional images, the mean fiber area and size distribution of muscle fibers in the quadriceps muscle are presented in A, B and C, respectively (n = 5/group). Fold changes in quadriceps MHC mRNA expression levels relative to vehicle-treated mice are summarized (n = 5/group)(D). Citrate synthase activity was measured in soleus and tibialis anterior muscles (E). Data are represented as mean +/− SEM *, # and § indicate p<0.05, 0.01 and 0.001, respectively.