Experimental study on the induction of bone marrow stromal cells differentiating into cardiomyocyte-like cells with cardiomyocytes in vitro

Objective: To investigate the feasibility of bone marrow stromal cells (BMSCs) differentiating into cardiomyocyte-like cells in heterogeneous cardiomyocytes microenvironment in vitro. Methods: Mouse GFP-BMSCs were isolated by centrifugation through a Ficoll step gradient and purified by plating culture and depletion of the non-adherent cells. Neonatal rat cardiomyocytes (CMs) were isolated by enzymatic dissociation from hearts of 1-to 2-day-old Sprague-Dawley (SD) rats and differentially plated to remove fibroblasts. Mouse GFP-BMSCs were cocultured with neonatal rat CMs through direct and indirect contact, respectively. Cardiomyogenic differentiation of BMSCs was evaluated by immunostaining with anti -α-actin monoclonal antibody and observing synchronous contraction with adjacent CMs by phase contrast microphotography. Results: On day 7 of coculture, GFP-BMSCs (CMs : BMSCs = 4 : 1)attached to nonfluorescent contracting cells (rat-derived CMs) showed myotube-like formation and started to contract synchronously with adjacent cardiomyocytes. About 10% of the fluorescent GFP-BMSCs were cardiomy-ocyte-like cells as determined by cell morphology and positive actin staining. Conclusion:Direct cell-to-cell interaction with CMs is crucial for cardiomyogenic differentiation of BMSCs in heterogeneous CMs microenvironment in vitro. This provides a novel inducing pathway for directional differentiation of cardiovascular tissue engineering seed cells.

Objective：To investigate the feasibility of bone marrow stromal cells （BMSCs） differenti ating into cardiomyocyte like cells in heterogeneous cardiomyocytes microenvironment in vitro. Methods： Mouse GFP-BMSCs were isolated by centrifugation through a Ficoll step gradient and purified by plating culture and depletion of the non-adherent cells. Neonatal rat cardiomyocytes （CMs） were isolated by enzymatic dissociation from hearts of 1-to 2-day old Sprague-Dawley （SD） rats and differentially plated to remove fibroblasts. Mouse GFP-BMSCs were cocuhured with neonatal rat CMs through direct and indirect contact, respectively. Cardiomyogenic differentiation of BMSCs was evaluated by immunostaining with an- ti-a-actin monoclonal antibody and observing synchronous contraction with adjacent CMs by phase contrast microphotography. Results： On day 7 of cocuhure, GFP-BMSCs （CMs ： BMSCs：4 ： 1）attached to nonfluorescent contracting cells （rat-derived CMs） showed myotube-like formation and started to contract synchronously with adjacent cardiomyocytes. About 10% of the fluorescent GFP-BMSCs were cardiomyocyte-like cells as determined by cell morphology and positive actin staining. Conclusion;Direct cell to-cell interaction with CMs is crucial for cardiomyogenic differentiation of BMSCs in heterogeneous CMs microenvironment in vitro. This provides a novel inducing pathway for directional differentiation of cardiovascular tissue engineering seed cells.