Similarly, in a rat model of ischemia EGF alone induced proliferation and some NSPC migration but did not promote regeneration unless combined with a later administration of erythropoietin (Epo) (Kolb et al., 2007), with similar results obtained for infusion of TGFα in a PD model (Cooper and Isacson, 2004). This evidence concerns the gene EPO and Parkinson disease.