Rat Mesenchymal Stem Cells Can Be Induced Into Cardiomyocytes In Vitro

Regeneration of cardiac myocytes in vivo is a problem in medical science which should be solved as soon as possible. Because there is often damaged myocardium in heart disease patients which can cause a progressive impairment of cardiac funtion. Bone mesenchymal stem cells(MSCs) have multipotentiality, so they give us a new field and a new method in regeneration of cardiac myocytes in vivo.In our study, we separated rat meseachymal stem cells(rMSCs) and cultured in vitro. Then we induced them into cardiomyocytes by means of adding 5-azacytidine(5-Aza) into medium and identified them. We have got some useful results in this study.METHODS rMSCs were isolated by percoll separating medium and cultured in vitro, observing rMSCs biologic characteristics. Then rMSCs were induced by 5-Aza with different concentration for 24h. After cultured for additional 4 weeks, we identified that some of the induced rMSCs had diffrentiated into cardiomyocytes by the means of transmission electron microscopy technique? immunocytochemistry technique and western blot technique. And we attempted to detect rest potential(RP) and action potential(AP) of induced rMSCs by the means of patch clamp technique to study their electrophysiological characteristics preliminary.RESULTS rMSCs isolated by percoll separating medium had higerpurity and better uniform in the process of culture in vitro. 5-10 # mol/L 5-Aza is a optimal concentration for rMSCs to differentiate into cardiomyo-cytes. Some of the induced rMSCs were positive expression of a -actin, cardiac troponin I(cTnl). Electron microscopy revealed myofilament-like structure, rich glycogen granules and a number of mitochondria. Western blot showed cardiac specific structure protein cTnl had been expressed. Some of induced rMSCs had approximal RP compared with normal rat cardiac myocytes, but AP could not be provocated.CONCLUSION 1) Percoll separating medium is a well-referenced medium for density gradient centrifugation of MSCs; 2) The optimal conditions for rMSCs to differentiate into cardiomyocytes are 5-10 # mol/L 5-Aza; 3) MSCs are mutipotential stem cells and they can be induced into cardiomyocytes by 5-Aza in vitro which have the characterestics of cardiac myocytes in structure.