Effects of biomimetic electrical stimulation on inducing differentiation of rat bone marrow mesenchymal stem cells into cardiomyocyte-like cells in isolated myocardium

Objective To explore the effects of biomimetic electrical stimulation on inducing differentiation of rat bone marrow mesenchymal stem cells(MSCs) into cardiomyocyte-like cells in isolated myocardium.Methods MSCs and cardiac myocytes from SD rats were isolated and cultured by modified method.MSCs were then co-cultured with cardiac myocytes(MSCs/ cardiomyocyte co-culture system).The co-culture system was divided into stimulated group and non-stimulated group.MSCs cells in stimulated group were given supra-threshold square biphasic pulses stimulation(5ms duration,0.5Hz,10V) lasting for 2h each day,while in non-stimulated group were routinely cultured.Each group was divided into three subgroups according to the incubation time of 3,5 and 7 days.The characteristic morphology of MSCs in every subgroup was observed under light microscope.The expression of cTnT in MSCs was detected by immunofluorescence.The rate of cTnT positive expression was also compared between two groups.Results The growth and frequency of myocardial wave of MSCs cells in stimulated group were better or higher than those in non-stimulated group.No expression of cTnT was detected in non-stimulated group at the 5th day of the experiment,while a few MSCs cells in the stimulated group expressed cTnT at the same time point.The cTnT expression was detected in the MSCs cells in the both groups on the 7th day.The rate of cTnT positive expression in stimulated group(20.98%±5.55%) was significantly higher than that in non-stimulated group(13.20%±3.98%,P0.05) at this time point.Conclusion Biomimetic electrical stimulation could promote the differentiation of rat bone marrow MSCs to cardiomyocyte induced by microenvironmental factors of cardiomyocyte in vitro,which with earlier exhibition of cardiomyocyte-like cells,and higher efficiency of differentiation rate.