Engraftment and survival of green fluorescent protein-positive (GFP+) cardiac mesenchymal stem cells (CMSCs) immediately and 1 week after cell transplantation in chagasic mice. (A) The tracking of GFP+ CMSCs in chagasic mice was performed immediately in cell transplantation by using an in vivo image system. Arrow indicates a GFP+ fluorescent dot in the heart of a chagasic mouse after intramyocardial injection in the left ventricle wall. (B, C) Heart sections of CMSC-treated mice 1 week after intramyocardial injection show the engraftment and survival of GFP+ cells (green) in chagasic heart by confocal microscopy analysis. GFP+ cells in the tissue did not co-express the cardiomyocyte markers (red) troponin T (B) or connexin 43 (C). Sections were co-stained with 4,6-diamidino-2-phenylindole (DAPI) (blue) for nuclei visualization. Bars represent 20 μm.