Figure 5.

Mdm2 is indispensable for exercise-induced angiogenesis in skeletal muscle. A) Representative immunoblots and densitometry analysis of the ratio of Mdm2 to β-actin in plantaris muscles from sedentary (Sed.) and endurance-trained (Tr.) female Sprague-Dawley rats (n=8/group). B) Detection of capillaries after alkaline phosphatase staining on plantaris muscle cross sections from rats described in A and determination of the capillary/fiber ratio. Scale bar = 50 μm. C) Representative immunoblots for CD31 (endothelial marker) and β-actin and ratio of CD31 to β-actin in plantaris muscles from rats described in A, B. β-Actin was used as a loading control. Data are means ± se (n=8 rats/group). *P ≤ 0.05; **P ≤ 0.01. D) Staining of capillaries with isolectin B4 on plantaris muscle cross sections from sedentary (Sed.) and trained (Tr.) wild-type and Mdm2-deficient (Puro/Δ7-9) mice, and determination of the capillary/fiber ratio. Data are means ± se (n=5 mice/group). NS, nonspecific. Two-way ANOVA shows an overall effect of the genotype. ***P ≤ 0.001 vs. sedentary wild-type mice; 2-way ANOVA and post hoc comparison.