Influence of hypoxic stimulation on angiogenesis and satellite cells in mouse skeletal muscle - Fig 4

mRNA expression in both hypoxic groups compared with each N group in the soleus (A, B) and superficial portion of the gastrocnemius (C, D) muscles from young and old mice. Gray and black bars represent continuous hypoxia (H) and intermittent hypoxia (IH) groups, respectively. Values are the mean ± SE. †: Significant difference from the N groups for each gene (P P P P = 0.013 in H vs. N), BDNF (P = 0.002 in H vs. N), MHCe (P = 0.035 in H vs. N), Atrogin1 (P = 0.011 in H vs. IH), and myostatin (P = 0.020 in IH vs. N) mRNA expression. On the other hand, a significant decrease was observed in the VEGF-A (P = 0.044 in H vs. N) mRNA and PGC1α (P = 0.005 in H vs. N, P = 0.035 in IH vs. N) mRNA expression. (B) In the old soleus muscle, VEGF-A (P = 0.009) and nNOS (P = 0.035) mRNA expression was significantly increased. In the IH groups, myostatin mRNA expression was significantly higher than that in the N groups (P = 0.011). The mRNA expression in old mice was higher in VEGF-A (H: P = 0.001, IH: P = 0.001), nNOS (H: P = 0.001, IH: P = 0.001) and PGC1α (H: P = 0.001) than in the young mice, and was lower in BDNF (H: P = 0.039) and FGF2 (IH: P = 0.031) than in the young mice. (C) In the young gastrocnemius muscle, VEGF-A mRNA was significantly increased (P = 0.016 in H vs. N). FGF-2 mRNA expression was significantly higher than that in the N groups only in the gastrocnemius muscle of the IH groups (P = 0.028). In the IH groups, the expression of MyoD (P = 0.049), VEGF-A (P = 0.001), FGF-2 (P = 0.005), and PGC-1α (P = 0.014) mRNA was significantly higher than that in H groups. (D) The expression of myogenin (P = 0.024) and ATG5 (P = 0.028) mRNA was higher in the H groups than in the IH groups. The expression of pax7 (P = 0.022) and myogenin (P = 0.048) in the old IH groups was lower than that in the young IH groups.