AIM: To evaluate the method of inducing mouse embryonic stem (ES) cells in vitro to differentiate into cardiomyocytes without using any chemical reagents.METHODS: BRL conditioned medium was used to promote the growth of ES cells and maintain them in an undifferentiated state before the experiment of differentiation. Then a three-step method including ES cell culture in hanging drops and in suspending was used to induce the differentiation of ES cells. RESULTS: Rhythmically contracting cells were observed among differentiated cells, which were proved to be cardiomyocytes with electron microscope and immunocytochemistry. CONCLUSION: A simple and economical method was established to induce mouse ES cells cultured in vitro to differentiate into cardiomyocytes without using any chemical reagents. [

AIM: To investigate the effect of human iNOS gene transfection on blood pressure in SD rats. METHODS: Human iNOS cDNA was transfected using gene transfection technique via enterocolia. The iNOS gene expression in rat celiac macrophages was also observed. RESULTS: The significant lowering of blood pressure in rats transfected with iNOS gene was observed from second day to sixth day after transfection, compaered to the control group ( P

AIM: To study the electrophysiological characteristics of ion channels of stem cell derived cardiomyocytes (SCDC) of mouse. METHODS: Embryonic stem cells of D 3 line (ES-D 3) were cultured on the MEF feeder layer with BRL conditioned medium, and fetal mouse heart cells(FMHC)were cultured in vitro. Then ES-D 3 cells were induced to differentiate into many kinds of cells. SCDC were harvested on day 12 after differentiation initiating and identified by electro-microscope and immunocytochemistry. SCDC and FMHC were prepared for the patch-clamp research. Sodium and calcium currents together were elicited and compared between SCDC and FMHC. RESULTS: The current characteristics of sodium and calcium channels of SCDC were very similar to FMHC. CONCLUSION: The functional expression of ion channels occurred during ES-D 3 cells differentiation and the electrophysiological characteristics of sodium and calcium channels of SCDC are very similar to FMHC.