(A) The representative images of live and dead cell staining. C17.2 cells were cultured with indicated concentrations of GDF11. Images were obtained at 200× magnification by inverted fluorescence microscope. The live cells were stained with calcein AM in green, and the dead cells were stained with EthD-1 in red. (B) GDF11 induced apoptosis in C17.2 neural stem cells. C17.2 cells were treated with vehicle or GDF11 (12.5, 25, 50 and 100 ng/mL) for 48 h and cell distribution was analysed using Annexin V-FITC and PI dual staining. The FITC and PI fluorescence was measured by flow cytometer with FL-1 and FL-2 filters, respectively. Lower left quadrant–live cells (Annexin V−/PI−), lower right quadrant–early/primary apoptotic cells (Annexin V+/PI−), upper right quadrant–late/secondary apoptotic cells (Annexin V+/PI +) and upper left quadrant–necrotic cells (Annexin V−/PI+). (C) The viability of C17.2 cells after 24 h or 72 h of cultivation with various concentrations of GDF11 or vehicle was measured using CCK-8 method. N = 3, p < 0.05. (D) Cumulative population doubling levels of C17.2 cells supplemented with different GDF11 concentrations for a total period of 6 passages. N = 4, *p < 0.05 compared with control. (E) Quantitative analyses of the GDF11 effect on apoptosis. N = 3, *p < 0.05 versus with vehicle control and **p < 0.01 versus with vehicle control.