Traditional ideas are that central nerve system (CNS) is difficult to regenerate due to deficiency of NTFs.

• 以往认为CNS损伤后难以再生是由于缺乏再生的NTFs，但是大量的实验研究表明，中枢神经损伤后，单纯给予NTFs并不能取得明显的再生效果。