Abstract: Objective To investigate the viability of tissue-engineered heart valve leaflets prepared with cell-polymer constructs in nude mice.Methods Sheep endothelial cells and smooth muscle cells/fibroblasts were seeded on patches of PHA and implanted subcutaneously in athymic mice(BALB/C).The cell-polymer constructs were harvested 12,14,21 and 28 days after implantation.Results Fourteen days after implantation,the cell-polymer constructs exhibited similar color with the autologous tissues,and HE staining showed more numerous cells in the implant.At 28 days following implantation,muscular fibers were formed in the cell-polymer constructs.V-G staining showed positive collagen staining in the implant at 12 days after implantation,while the control implants retrieved 28 days after implantation did not show extensive tissue formation or muscular fiber formation.Conclusion The cell-polymer constructs can survive in vivo and has the potential to grow into autologous valve leaflets in the nude mice.