Neurotrophins are well known for their beneficial effects on neurite outgrowth and neuroprotection. Neurotrophin-3(NT-3) is one of important factors in regenerative milieu and exerts variety of physiological effects on nervous system development. Many studies are focused on the usage of NT-3 stimulating nerve regeneration, but the safe and efficient delivery of NT-3 to the site of injury is still problematic because of its short half-life and the barrier between brain and vessel. Gene transfer technique provides a new strategy for application of NT-3 and allows insertion of NT-3 gene into OEG, which would then produce NT-3 continuously and exert the physiological action.