心肌细胞对骨髓间充质干细胞分化为心肌细胞的影响

目的：观察大鼠成体心肌细胞对骨髓间充质干细胞（mesenchymal stem cells，MSCs）定向分化的诱导作用。方法：应用Percoll’s密度梯度离心法分离培养大鼠MSCs，传2代后用流式细胞术检测其表面CD34,CD71和CD90的表达，然后用Lipofectamine2000介导pEGFP-N3转染标记MSCs。将GFP标记的MSCs与新鲜分离的成体大鼠心肌细胞分别按接触、非接触（MILLICELLTM-HA半透膜分层培养）及心肌细胞条件培养液培养。1周后应用免疫荧光检测MSCs α-actin，desmin和cTnT的表达。结果：接触培养组中可见表达GFP的MSCs细胞同时表达α-actin,desmin和cTnT，而分层培养组及条件培养组中均未见α-actin，desmin和cTnT的表达。结论：大鼠成体心肌细胞与MSCs接触培养，可能诱导MSCs分化为心肌细胞。

Differentiation of mesenchymal stem cells into cardiomyocytes induced by cardiomyocytes

OBJECTIVE: To investigate the role of adult cardiomyocytes in the differentiation of mesenchymal stem cells (MSCs) into cardiomyocytes. METHODS: Rat MSCs were isolated by a Percoll's gradient solution and cultured in low-glucose Dulbecco' s modified Eagle' s medium (DMEM). After 2 passages, cell-surface antigen CD34, CD71 and CD90 for rat MSCs were determined by flow cytometry, and these MSCs were transfected with pEGFP-N3 by Lipofectamine2000. Then those MSCs labeled with GFP, were cultured in contacted, nocontacted and conditioned with adult rat myocardiocytes. Immunofluorescence staining against alpha-actin, desmin, and troponin-T were performed after 1 week. RESULTS: Immunofluorescence staining was positive against alpha-actin, desmin, and troponin-T on MSCs in contacted culture group. In contrast, no alpha-actin, desmin, and troponin-T expression on MSCs were observed in the noncontacted culture group and the conditioned culture group. CONCLUSION: Direct cell-to-cell contact between MSCs and adult cardiomyocytes may induce differentiation of MSCs into cardiomyocytes.