It should be noted that the apoptosis caused by ProTα is prevented by the addition of growth factors, such as brain-derived neurotrophic factor (BDNF), as shown in an in vitro culture study using cortical neurons [26] and an in vivo study in a rat middle cerebral artery occlusion (MCAO) model [28] and a mouse retinal ischemia–reperfusion model, respectively [29]. Here, BDNF is linked to retinal ischemia.