DAF reduces neuronal cell death induced by ischemia. Primary rat cortical neurons were exposed to glucose free medium containing 1.5 mM NaCN for 1 hr, then recovered in normal medium with and without DAF for 24 hours. (a) The effects of DAF on the apoptosis of primary cultured neuronal cells as measured by TUNEL assay. DAPI localizes the nucleus (blue), TUNEL shows DNA fragmentation (green), and NF200 shows neurons (red). Positive cells were counted and considered as apoptotic cells (n = 5). Scale bar = 20 μm. (b) The apoptotic cells were counted as described in the methods and the cumulative data from five independent experiments was shown here. (c) The neuronal viability determined by MTT assay (n = 5). (one-way ANOVA followed by Newman-Keuls test. * p < 0.05 and **p < 0.01).