Distribution of nerve growth factor (NGF) in incised skin. (A) Skin samples were collected from area A (1 mm surround the incision) or area B (1 mm outside area A). (B) Western blot of NGF from areas A and B on postoperative day (POD) 2. (C) NGF levels from areas A and B on POD 2 compared with sham-operated skin. *P< 0.05versussham. n = 3 per group.