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

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 1x10 super(7)/L. Different amounts of basic fibroblast growth factor (0, 25, 50, 100 mu g/L) (0 mu g/L served as control) were used in C17.2 neural stem cells (200 mu 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 fibroblast 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 basic fibroblast growth factor was 100 mu g/L, without cytotoxicity. Results of flow cytometry demonstrated that apoptotic rate of C17.2 neural stem cells in the control group was higher than in the 25, 50 mu g/L basic fibroblast growth factor group (P < 0.01). There had significant differences in apoptotic ratio among 25, 50 and 100 mu g/L basic fibroblast growth factor groups (P < 0.05-0.01). CONCLUSION: Exogenous basic fibroblast growth factor has obvious inhibitory effect on radiation-induced apoptosis in C17.2 neural stem cells.