外源性碱性成纤维细胞生长因子对放射诱导神经干细胞凋亡的抑制效应

Inhibitory effect of exogenous basic fibroblast growth factor on radiation-induced apoptosis in C17.2 neural stem cells

背景：已证实放射性神经干细胞损伤是放射性脑损伤的可能途径之一，而碱性成纤维细胞生长因子对放射性损伤具有保护作用，但其机制尚不清楚。目的：观察外源性碱性成纤维细胞生长因子对放射诱导C17．2神经干细胞凋亡的抑制作用。设计、时间及地点：随机分组设计，对比观察，于2006-11／2008—06在中山大学附属第二医院林百欣实验中心完成。材料：C17．2神经干细胞系为小鼠小脑祖细胞永生化后构建的神经干细胞系。方法：以直线加速器进行总量为8Gy外照射C17．2神经干细胞建立离体放射性损伤模型，以1×10^7L^-1的细胞浓度接种C17．2神经干细胞悬液至96孔板，每孔加细胞悬液200uL，按0，25，50，100μg／L（0μg／L作对照）分别加入碱性成纤维细胞生长因子干预。主要观察指标：四甲基偶氮唑盐法检测细胞活性并拟合生存曲线，流式细胞仪检测细胞凋亡率。结果：随碱性成纤维细胞生长因子浓度升高，C17．2神经干细胞增殖比明显增加（P〈0．01），呈现明显剂量效应关系。碱性成纤维细胞生长因子浓度为100ug／L时活性最强，未显示细胞毒性。流式细胞仪检测结果显示：对照组细胞凋亡率高于25，50ug／L碱性成纤维细胞生长因子组（P〈0．01），25，50，100μg／L碱性成纤维细胞生长因子组组间相比，差异具有显著性意义（P〈0．05～0．01）。结论：外源性碱性成纤维细胞生长因子对放射诱导的C17．2神经干细胞凋亡具有明显抑制作用。

BACKGROUND： It had been verified that injuries of neural stem cells after radiation were a possible mechanism of radiation-induced injuries of the brain （RIB）. Basic fibroblast growth factor had been confirmed to have protective effect on RIB, but the mechanism was not clear, OBJECTIVE： To explore the inhibitory effect of basic fibroblast growth factor on radiation-induced apoptosis in C17.2 neural stem cells. DESIGN, TIME AND SETTING： The randomized controlled study was performed at the Lin Binxin Research Center of Second Affiliated Hospital of Sun Yat-sen University from November 2006 to June 2008. MATERIALS： C17.2 neural stem cell was constructed from the cerebellum progenitor cell of mouse after been immortalized. METHODS： C17.2 neural stem cell was radiated by accelerator linear （8 Gy） to establish the radiation model in vitro, and then incubated in a 96-well plate at 1 × 10^7/L. Different amounts of basic fibreblast growth factor （0, 25, 50, 100 μ g/L） （0 μ g/L served as control） were used in C17.2 neural stem cells （200 μ L per well）. MAIN OUTCOME MEASURES： Cell activity and survive curve were determined by MTT assay. Apoptotic rate was detected by flow cytometry. RESULTS： With the increase in basic fibreblast growth factor concentration, proliferation ratio of C17.2 neural stem cells was significantly increased （P 〈 0.01 ）, in a dose-effect relationship. The effect was the most significant when the concentration of basicfibreblastgrewth factorwas 100μg/L, withoutcytotoxicity. Results of flow cytometry demonstrated that apoptotic rate of C17.2 neural stem cells in the control group was higher than in the 25, 50μg/L basic fibroblast growth factor group （P 〈 0.01）. There had significant differences in apoptotic ratio among 25, 50 and 100μ g/L basic fibreblast growth factor groups （P 〈 0.05 0.01）. CONCLUSION： Exogenous basic fibreblast growth factor has obvious inhibitory effect on radiation-induced apoptosis in C17.2 neural stem cells.