体外“心肌样”环境诱导骨髓基质细胞向心肌细胞分化

A “Cardiac-like” Milieu in vitro Is Necessary for the Cardiomyogenic Differentiation of Marrow Stromal Cell

目的 :探讨体外“心肌样”环境对骨髓基质细胞 (marrowstromalcells ,MSCs)分化的诱导作用。方法 :体外将MSCs与心肌细胞共培养至 16d ,用数码显微摄像及免疫荧光技术分别记录和检测被标记MSCs的生长行为和心肌特异性肌节肌球蛋白重链 (cardiacmyosinheavychainα/ β ,MHCα/ β)、肌钙蛋白I(troponinI,TnI)的表达 ;并在同等条件下 ,与用心肌条件培养基及正常培养基培养的MSCs进行比较。结果 :正常培养基组与条件培养基组均未发现MSCs分化为心肌细胞的可靠证据。但在共培养组 ,观察到了搏动的MSCs;MHCα/ β与ThI蛋白分别于第 1,4d开始表达 ,随时间延长 ,表达阳性MSCs增多。结论 :体外MSCs与心肌细胞接触生长可向心肌细胞分化。

Objective: To investigate the cardiomyogenic differentiation of marrow stromal cells(MSCs)in a “cardiac-like”milieu in vitro. Methods: The MSCs were cocultured with neonatal rat cardiomyocytes for 16 days. The morphologic changes of MSCs and the expression of cardiac myosin heavy chain(MHCα/β)and troponinI(TnI)was recorded respectively with digital microscope camera system and immunofluorescence technique. And at the same condition,the MSCs cultured with cardiomyocyte conditioned medium and normal medium respectively were used as comparison. Results: All MSCs cultured as comparison did not show any myogenic phenotypes. In contrast,in cocultured group,spontaneously contracting MSCs were observed; and the MHC and TnI proteins-positive MSCs were recognized firstly on day 1 and day 4 respectively,and the positive cell number of MSCs increased with time. Conclusion: A direct cell-cell interaction with cardiomyocyte in vitro can trigger the cardiomyogenic differentiation of MSCs.