Figure 3. Endothelial progenitor cell expansion (CD34+ cells) in human skeletal muscle 24 h after squat exercise. The CD34+ cells and p16INK4a+ cells (B) are indicated by brown precipitates surrounding myofibers in immunohistochemical stains of muscle cross-section. (A) CD34+ cells were nearly doubled post exercise (C). Approximately 65% of CD34+ cells were colocalized with p16INK4a+ cells. This ratio was not much affected after exercise (60%) in the trained men. *denotes significant difference against Pre, p < 0.05; **denotes significant difference against Pre, p < 0.01. Abbreviations: Pre: before exercise; Post: 24 h after exercise. PLA: Placebo; Rg1: Ginsenoside Rg1.