Figure 2. Massive increases of senescent endothelial progenitor cells in human skeletal muscle 3 h after aerobic exercise (70% V̇O2max). Approximately 21-fold increases in senescent endothelial progenitor cells occurred 3 h after 1-h cycling exercise (70% V̇O2max), while Rg1 supplementation advances the increase immediately after exercise (~3-fold) and decline to baseline 3 h after exercise (A, C). Total endothelial progenitor cells (CD34+) surrounding myofibers were unaltered after exercise for both trials (B, D). Approximately 60% of elevated senescent endothelial progenitor cells was contributed by endothelial progenitor cells (p16INK4a+ / CD34+) (E, G), while the rest of 40% was contributed by infiltrated nucleated cells (p16INK4a+ / CD34-) (F, H). Scale bar = 30 μm. Data are expressed as mean and SEM. * Significant difference against Pre (Baseline), P < 0.01; † Significant difference against Placebo, P < 0.01. Abbreviation: PLA, Placebo.