间充质干细胞分化为心肌样细胞与P120连环蛋白mRNA表达

目的：研究5-氮杂胞苷（5-azacytidine，5-aza）诱导体外骨髓间充质干细胞（marrow measenchymal stem cells，MSCs）向心肌细胞发展的作用及其机制。方法：从Wistar大鼠骨髓中获得MSCs，培养传代后用不同浓度的5-aza诱导，倒置光显微镜和透射电镜观察诱导前后细胞形态变化；流式细胞术检测细胞周期改变；MTT法检测5-aza对MSCs生长的影响；免疫细胞化学法检测肌红蛋白、结蛋白和肌动蛋白的表达；RT-PCR检测P120连环蛋白1A mRNA的表达。结果：5-aza对MSCs有抑制增殖的作用（P〈0．05）；在光镜和透射电镜下可见有心肌样细胞的形态变化；免疫细胞化学检测结果表明，MSCs的经5-aza诱导14d，肌红蛋白、结蛋白和肌动蛋白的表达均较对照组显著增高（P〈0．01）；PT—PCR结果表明P120连环蛋白mRNA表达明显，而对照组未见表达。结论：MSCs可在体外被5-aza诱导分化成心肌样细胞，这可能与P120连环蛋白1A mRNA表达有关。

P120 catenin expression and transdifferentiation of mesenchymal stem cells into myocardium-like cells in vitro

Objective： To investigate P120 catenin expression and its roles in differentiation of marrow mesenchymal stem cells （MSCs） induced by 5-azacytldine （5-aza） into myocardium-like cells. Methods： MSCs derived from rat bone marrow were cultured in IMDM medium. The cultured cells were exposed to different concentrations of 5-aza for 14 days. The morphologic exchanges of MSCs were detected by inverted phase contrast microscope and transmission electron microscope. Cell cycle was analyzed by flowcytometry. The cell growth was examined by MTT assay. The markers of transdifferentiation such as actin, desmin and myoglobin were detected by immunocytochemistry. The expression of P120 Catenin 1A mRNA was detected by PT-PCR. Results： 5-aza at a 10μmol/L concentration inhibited the growth of MSCs. Morphologic changes of myocardium-like cells were seen by light microscope and transmission electron microscope. After MSCs were incubated in 5-aza medium for 14 d, the percentages of actin, desmin and myoglobin-positive cells increased significantly by immunocytochemistry （P〈 0.01 ）. The expression of P120Catenin 1A mRNA was found obviously in transdifferentiated cells, but no found in control group. Conclusion： The MSCs can transdifferentiate into myocardium-like cells in vitro by exposure to 5--aza, which may be related to the ex pression of P120 Catenin 1A.