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目的探讨力学刺激与成骨化学诱导剂对大鼠骨髓间充质干细胞(rat bone mesenchymal stem cellsr,BMSCs)碱性磷酸酶(alkaline phosphatase,ALP)I、型胶原(collagen type I,COL I)和骨钙素(osteocalcin,OCN)基因表达与钙化结节形成的影响。方法体外分离培养rBMSCs,分别在成骨诱导和非成骨诱导条件下应用双轴力学应变加载系统对rBMSCs施加周期性的机械张应变(应变2%,频率1 Hz,每次2 h,间隔2 h,每天加载3次)。力学刺激作用3 d和6 d,采用实时荧光定量RT-PCR检测ALP、COL I和OCN的mRNA表达,同时采用茜素红染色法观察钙化结节的形成情况。结果力学刺激作用后,成骨诱导6 d组出现明显的钙化结节,其余各组均无明显钙化结节形成。与相应非诱导组比较,成骨诱导3 d组ALP、COL I和OCN的mRNA表达量分别增加0.63、和11.8倍;成骨诱导6 d组ALP、COL I和OCN的mRNA表达量分别增加2.73、.2和10倍。结论成骨化学诱导剂和力学刺激均能促进rBMSCs的骨向分化,且二者之间具有协同作用。
Objective To investigate the effects of mechanical stimuli and osteoinductive agents on the expressions of alkaline phosphatase (ALP) I, collagen type I (COL I) and Bcl-2 in rat bone marrow mesenchymal stem cells Effect of osteocalcin (OCN) gene expression on the formation of calcified nodules. Methods The rBMSCs were isolated and cultured in vitro. The mechanical strain (strain 2%, frequency 1 Hz, 2 h each, interval 2) was applied to rBMSCs under biaxial mechanical strain loading system under osteogenic and non-osteoinductive conditions h, loaded 3 times a day). Mechanical stimuli were performed on day 3 and day 6, and mRNA expressions of ALP, COL I and OCN were detected by real-time fluorescence quantitative RT-PCR. Alizarin red staining was used to observe the formation of calcified nodules. Results After mechanical stimulation, obvious calcified nodules were observed on the 6th day after osteogenic induction, and no obvious calcified nodules were found in the other groups. Compared with the corresponding non-induced group, mRNA expression of ALP, COL I and OCN increased by 0.63 and 11.8 times respectively in the 3rd day after osteogenic induction; mRNA expression of ALP, COL I and OCN increased by 2.73 , .2 and 10 times. Conclusion Both osteogenic chemotactic agents and mechanical stimulation can promote the osteogenic differentiation of rBMSCs with synergistic effect.