Mobilization of bone marrow-derived cells. A–D: Blood samples were collected from the vehicle- or M-CSF-treated mice at baseline, 24 hours, and 72 hours after the MI. The percentage of Mac-1+/Gr-1−, CD34+/Flk-1+, and CXCR4+ cells was assessed by flow cytometric analysis. Results are expressed as mean ± SEM (n = 3). *P < 0.05, and **P < 0.01 versus vehicle.