地塞米松对大鼠骨髓间充质干细胞凋亡的影响

Effect of dexamethasone on bone marrow mesenchymal stem cells apoptosis in rats

背景：研究发现地塞米松能有选择性地促进骨髓间充质干细胞凋亡。目的：了解地塞米松对骨髓间充质干细胞凋亡的影响以及作用机制。方法：体外培养 SD 大鼠骨髓间充质干细胞,传至第 2 代后分两组培养,对照组不加地塞米松,实验组分别加入 10-9,10-8,10-7 mol/L 地塞米松,作用 3,6,12,24 h 后通过流式细胞仪检测凋亡率。MTT 法检测地塞米松对骨髓间充质干细胞增殖率的影响。取 10-7 mol/L 地塞米松作用骨髓间充质干细胞 24 h,反转录后检测 Caspase-3 和 bcl-2 的表达。结果与结论：与对照组比较,10-8,10-7 mol/L 地塞米松作用 12~24 h 对骨髓间充质干细胞的凋亡有明显促进作用,且与作用浓度和时间存在相关性,随着作用浓度的增大和时间的延长骨髓间充质干细胞的凋亡率有增高的趋势。MTT 结果表明10-8,10-7 mol/L 地塞米松作用 24 h 对骨髓间充质干细胞增殖率影响显著,这与上述流式细胞仪的检测结果相符。RT-PCR提示地塞米松作用组 Caspase-3 显著增高,bcl-2 降低。结果证实地塞米松可能是通过细胞外通路和（或）线粒体通路促进骨髓间充质干细胞凋亡。

BACKGROUND：Several studies have shown that dexamethasone can selectively promote bone marrow mesenchymal stem cells（BMSCs） apoptosis.OBJECTIVE：To observe the effect of dexamethasone on BMSCs apoptosis and mechanism of action.METHODS：BMSCs（the first generation） were cultured in vitro;BMSCs of passage 2 cultured were divided into 2 groups：control group and experimental group.Dexamethasone was not added into control group,10-9,10-8,and 10-7 mol/L concentration of dexamethasone was added into experimental group,respectively.Apoptosis rate was detected by flow cytometer after 3,6,12,24 hours.MTT assay was used to detect the effect of dexamethasone on proliferation rate of BMSCs.Effects of BMSCs which were deal with by 10-7 mol/L concentration of dexamethasone after 24 hours on Caspase-3 and bcl-2 were measured through RT-PCR.RESULTS AND CONCLUSION：Compared with the control group,10-8,10-7 mol/L concentration of dexamethasone had significant promotion on the apoptosis of BMSCs after 12-24 hours,which was relative to concentration of dexamethasone and time.With the effect of increasing concentration and prolonged time,the apoptosis rate of BMSCs had an increasing trend.The results of MTT showed that 10-8,10-7 mol/L concentration of dexamethasone had significant effect on the proliferation rate of BMSCs after 24 hours,which was consistent with the above-mentioned detection results of flow cytometer.RT-PCR indicated that the activity of Caspase-3 was increased significantly and activity of bcl-2 was decreased mildly.The results confirmed that dexamethasone promoted apoptosis of BMSCs through extracellular pathway and（or） mitochondria pathway.