In vivo comparison of regenerative activity and cardiac function after treatment with two sources of ADSCs. Rat pericardial (periADSCs) and inguinal ADSCs (ingADSCs) were intramyocardially injected into the infarcted heart, directly after injury. H&E staining demonstrated a significant increase of the wall thickness at the site where periADSCs were injected in comparison with that of ingADSCs 28 days after transplantation (upper panel, P < 0.01; n = 5 and 4). The site of periADSC injection comprised significantly more cardiomyocytes, suggesting a cardiogenesis induced by periADSCs injection (middle panel, P < 0.01; n = 5 and 4). Echocardiographic analysis revealed a restoration of contractile activity in the infarcted anterior wall and improvement of ejection fraction (EF) in periADSCs-treated heart (P < 0.05, n = 5 and 4). **P < 0.01 and *P < 0.05. Bar = 2 mm in the upper and 200 μm in middle panel.