title: Effect of substance P released from peripheral nerve ending on endogenous expression of epidermal growth factor and its receptor in wound healing.
abstract: OBJECTIVE
  To explore the relationship between substance P (SP) released from peripheral nerve endings and the expression of epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) during wound healing.
  
  
  METHODS
  Fifty Wistar rats were randomly divided into 2 groups, injury group and capsaicin group. In the injury group, a full-thickness skin wound on the back of the rat was taken. The wound edge and granulation tissues were taken on the 1st, 3rd, 6th, 9th, 12th days after injury, respectively. In the capsaicin group, capsaicin was injected subcutaneously on the back of the rats to destroy the sensory nerve to prevent the secretion of SP, then a wound and sample was made in the same way. Immunohistochemistry and in situ hybridization were employed to detect the expression of SP, EGF/EGFR, and EGF mRNA/EGFR mRNA in the granulation tissues.
  
  
  RESULTS
  In the injury group, immunohistochemical stain of SP and EGF/EGFR was located on the hair follicles and sebaceous glands at the 1st day. And the stain of SP was obvious at the 3rd day in the granulation tissues, then decreased gradually. EGF/EGFR was at low level at the 3rd day, then increased gradually and reached the peak at the 9th day, then declined. In the capsaicin group, the immunohistochemical stain of SP and EGF/EGFR was faint and without obvious change during the wound healing process. The tendency of the EGF mRNA/EGFR mRNA expression was similar to that of EGF/EGFR.
  
  
  CONCLUSIONS
  During wound healing, SP may promote the healing process by affecting the expression of EGF/EGFR in the granulation tissues.
authors.affiliation: Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China. laixinan@263.net
authors.forename: Xinan
authors.initials: X
authors.lastname: Lai
authors.forename: Zhengguo
authors.initials: Z
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Wei
authors.forename: Lili
authors.initials: L
authors.lastname: Wang
mesh_terms: D000818:Animals; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D006097:Granulation Tissue / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013373:Substance P / Q000502:physiology*; D014945:Wound Healing / Q000502:physiology*
chemical_list: D013373:Substance P; D004815:Epidermal Growth Factor; D066246:ErbB Receptors