BDNF and peripheral nerve injury: Previous studies on Slit focusing on SCs suggested that peripheral nerve injury could lead to the expression of various neurotrophic factors in SCs, including NGF, BDNF, neurotrophin 4/5, insulin growth factor 1 and 2 (Scheib and Hoke, 2013), and Slit2 and Slit3 (Carr et al., 2017).