Fig. (1) Lac-Z labeled MSCs (blue) prior to implantation in culture dish. B: (Group NB) Cross-section of myocardium 3 weeks after implantation showed no labeled MSCs in a normal growing heart. Stained with X-gal and counterstained with hematoxylin and eosin. C: (Group AL) Cross-section of myocardium 1 week after implantation showed Lac-Z positive cells in the infarcted area. Stained with X-gal and counterstained with hematoxylin and eosin. Black arrows show X-gal positively stained cells. D: (Group BL) Cross-section of myocardium 1 week after implantation showed Lac-Z positive cells in the infarcted area. Stained with X-gal and counterstained with hematoxylin and eosin. Black arrows show X-gall positively stained cells. E: (Group AL) Cross-section of myocardial scar 6 weeks after coronary ligation showed Troponin I-c positive cells. Brown color in the cytoplasm indicates positive stain. Counterstained with hematoxylin. Black arrow showed Lac-Z positive cell. F: (Group BL) Cross-section of myocardial scar 6 weeks after coronary ligation showed Connexin-43 positive cells in the peri-infarcted area. Counterstained with hematoxylin. The red arrows show Connexin-43 positive staining. Black arrow shows Lac-Z positive stained cells.