血管生成素1增强骨髓间充质干细胞缺血环境下生存能力的研究

目的 研究血管生成素1（Ang1）对骨髓间充质干细胞（MSCs）在缺血清状态下的保护作用,探索一种改善MSCs生存能力的方法.方法 建立体外缺血清的凋亡模型,应用四甲基偶氮唑盐检测MSCs的生存能力,双苯并咪唑染色评估MSCs的凋亡,蛋白质印迹分析（Western-blot）检测丝氨酸/苏氨酸蛋白激酶（Akt）细胞生存通路的表达.结果 MSCs在缺血清处理24h后.生存能力降至（72.7±5.8）%,Ang1能够明显改善MSCs的生存能力,并呈剂量依赖性,在50μg/L时达到了高峰,生存能力提高至（92.3±1.5）%（P〈0.01）;Ang1能够降低MSCs的凋亡率,从（24.9±3.9）%降至（11.0±2.4）%（P〈0.01）;缺血清明显降低了MSCs的Akt磷酸化水平,但Ang1能够明显增加MSCs的Akt活化;应用P13K,Akt通路阻滞剂Wortman-nin后,Ang1的保护作用消失,MSCs的生存能力从（92.3±1.5）%降至（73.9±4.7）%（P〈0.01）,凋亡率从（11.0±2.4）%回升至（26.5±2.6）%（P〈0.01）. 结论 Ang1能够改善MSCs的生存能力.作用机制可能与激活P13K/Akt生存通路有关.

Angiopoietin-1 Enhances Mesenchymal Stem Cell Survival Under Serum Deprivation and Its Mechanism

Objective To investigate whether angiopoietin-1 （Ang1） can protect mesenchymal stem cells （MSCs） against serum deprivation and explore a new method to enhance MSCs survival. Methods Serum deprivation was used in vitro to induce MSCs apoptosis, A 3-（4,5-dimethylthiazol-2-yl ）-2,5-diphenyl-tetrazolium bromide assay was applied to evaluate MSCs survival and Hoechst staining to detect apoptosis. The expression of serine-threonine kinase Akt signal transduction pathway was detected by western-blot. Results The survival rate of MSCs decreased to （72.7 ±5.8 ）% after 24 hours of serum deprivation. Angl improved MSCs survival in a dose-dependent manner with the highest survival rate of （92.3 ± 1.5 ）% at the concentration of 50ug / L and reduced MSCs apoptosis from （ 24.9 ±3.9 ）% to （ 11.0 ± 2.4 ）% （ P 〈0.01 ）. Serum deprivation significantly reduced, while Angl increased, phosphorylated Akt of MSC s. A PI3K / Akt inhibitor wortmannin blocked the effect of Angl, manifested as a reduction of survival [（ 73.9± 4.7 }% ] and an increase of apoptosis [（26.5 ± 2.6）%] of MSCs. Conclusion Angl can improve MSCs survival and the activation of PI3K / Akt pathway may be the possible mechanism.