骨髓间充质干细胞分化能力及Notch通路活性的增龄性变化

目的： 在体外实验中初步探索骨髓间充质干细胞（bone marrow mesenchymal stem cells,BMSCs）成骨、成脂分化能力及细胞活性的增龄性变化,以及在增龄过程中Notch信号通路活性的改变。方法： BMSCs取自年轻、成年及老年C57BL/6小鼠全骨髓,以流式细胞术鉴定细胞表面抗原,成骨、成脂诱导评价各组细胞的分化能力,细胞增殖、迁移实验检测各组细胞活性,实时荧光定量PCR（qPCR）检测Notch相关基因的表达。采用SPSS 19.0软件包对数据进行统计学分析。结果： 茜素红和油红O染色结果表明,BMSCs的成骨分化能力随着年龄增长而下降（P<0.05）,成脂分化能力随着年龄增长而提高（P<0.05）。细胞活性实验表明,细胞增殖能力和迁移能力未随着年龄增长而下降（P>0.05）。qPCR结果表明,老龄组BMSCs的Notch信号通路表达水平显著高于年轻组（P<0.05）。结论： 随着个体年龄增长,BMSCs呈现出成骨分化能力下降而成脂分化能力提高的现象,Notch信号通路活性呈现出增龄性升高,为恢复老龄BMSCs受损成骨分化能力提供了新的思路。

Age-related changes in differentiation of bone marrow mesenchymal stem cells and the activity of Notch signaling pathway

PURPOSE: To explore the age-related changes in differentiation and proliferation of murine bone marrow mesenchymal stem cells (BMSCs) and the activity of Notch signaling pathway in vitro. METHODS: BMSCs were harvested from the whole bone marrow of young, adult and aged C57BL/6 mice and were evaluated for cell-surface protein expression using flow cytometry. After osteogenic and adipogenic induction, osteogenic and adipogenic differentiation ability of BMSCs was evaluated. Cell viability was analyzed by proliferation and migration assays. The expressions of Notch-related genes were analyzed by real-time PCR. The experimental data were analyzed with SPSS 19.0 software package. RESULTS: Alizarin red S and Oil red O staining results indicated that the osteogenic ability of BMSCs gradually decreased with aging, while the adipogenic ability increased. Cell activity assays showed that the proliferative and migrated capacity did not decline with aging significantly, which suggested that the changes of osteogenic and adipogenic differentiation observed in aged BMSCs were not attributed to cell activity but to differentiation potential. Real-time PCR showed the aged cells exhibited significantly higher Notch signaling expression level than the younger ones (P<0.05). CONCLUSIONS: Decreased bone formation capacity and increased adipogenic differentiation ability were noted in aged BMSCs. At the same time, the activity of Notch signaling pathway shows an aging increase which would propose a new idea to restore the damaged osteogenic differentiation ability of aged BMSCs.