2 weeks after the insult, the RGC densities in the central and mid-peripheral retinas in ON-crushed, G-CSF-treated rats were significantly higher than that of the corresponding ON-crushed, PBS-treated rats (survival rate was 60% vs. 19.6% in the central retina, 46.5% vs. 23.9% in mid-peripheral retina, respectively, p<0.001). FVEP measurements showed a significantly better preserved latency of the p1 wave in the ON-crushed, G-CSF-treated rats than the ON-crushed, PBS-treated rats (78+/-9 ms in the sham operation group, 98+/-16 ms in the G-CSF-treated group, and 174+/-16 ms in the PBS-treated group, p<0.001).;In mice subjected to controlled cortical impact (CCI) we show that treatment with granulocyte macrophage colony stimulating factor (GM-CSF) affects regulatory T cell numbers coincident with decreased lesion volumes and increased cortical tissue sparing. This paralleled increases in neurofilament and diminished reactive microglial staining.