摘要
目的研究骨形态发生蛋白-2(BMP-2)对骨髓源性心肌干细胞(MCSC)向心肌分化的作用,探讨MCSC向心肌分化中的BMP-2信号转导机制.方法从SD大鼠骨髓中筛选MCSC,用BMP-2诱导向心肌定向分化.RT-PCR检测诱导前后BMP-2受体BMPRIA和BMPRII、心肌早期转录因子Nkx2.5和GATA-4以及cTnT mRNA的表达.免疫细胞化学标记诱导后细胞cTnT和Cx-43的表达.结果用BMP-2诱导后,MCSC的形态和排列发生变化.RT-PCR检测结果显示,诱导前BMPRIA和BMPRII以及Nkx2.5和GATA-4呈低表达,诱导后1周表达增加,3～4周表达明显.cTnT mRNA在诱导前不表达,诱导后1周开始表达,3～4周表达明显.免疫细胞化学染色显示,cTnT和Cx-43从诱导后2周开始表达.3～4周cTnT表达增强,呈现密集的横纹样结构.Cx-43在2周位于细胞膜下,3周分布于相邻细胞连接处,4周呈颗粒状密集分布于肌管的相邻细胞连接处. 结论BMP-2通过BMPRIA和BMPRII的介导作用诱导MCSC分化为心肌细胞.
Objective To investigate the effects of BMP-2 on differentiation of the marrow-derived cardiac stem cells （MCSCs） towards cardiomyocytes and to explore mechanism of signal transduction of BMP-2 in differentiation of MCSCs towards cardiomyocytes. Methods MCSCs were selected from the marrow of SD rats and were induced with BMP-2 to differentiate towards cardiomyocytes. Expression of receptors （BMPRIA and BMPRII） of BMP-2, cardiac transcription factors （Nkx2.5 and GATA-4）, and cTnT mRNA were examined with RT-PCR before and after induction. Expression of cTnT and Cx-43 of the cells after induction were ladetected with immunocytochemistry. Results Shape and arrangement of the cells changed after induction with BMP-2. In RT-PCR analysis, expression of BMPRIA and BMPRII, Nkx2.5 and GATA-4 were low before induction. The expressions increased one week after induction. High expressions was observed three to four weeks after induction. Expression of cTnT mRNA was not observed before induction. It expressed one week after induction, its expression was high three to four weeks after induction. In immunocytochemical staining, cTnT and Cx-43 was expressed two week after induction. Expression of cTnT was strong three to four weeks after induction. The structure was dense and striation-like. Cx-43 was located beneath the membrane two weeks after induction. In three weeks after induction, the protein was observed at cell conjunctions. It was granular and dense, and located at conjunctions between cells of myotube-like structure four weeks after induction. Conclusion BMP-2 induces differentiation of MCSCs into cardiomyocytes via mediation of BMPRIA and BMPRII.
出处
《解剖学报》
CAS
CSCD
北大核心
2005年第5期498-502,共5页
Acta Anatomica Sinica
基金
国家自然科学基金资助项目(30470883)
