In the previous decade, exogenous neurotrophic factors such as brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), and glial cell line-derived neurotrophic factor (GDNF) have been investigated in the treatment of peripheral nerve injuries or ED following cavernous nerve injury [7, 8]. The gene discussed is BDNF; the disease is peripheral nerve injury.