Background: Improving the survival of transplanted cells is a critical is- sue in the use of stem cell transplantation therapy for cardiovascular disease. Many transplanted cells are lost through apoptosis or necrosis triggered by hypoxia or superoxide. Methods and Results: Tongue muscle-derived Sca-1(+) cells were isolated from the mouse and cultured for 2 weeks and then exposed to hydrogen peroxide (H_2O_2