OBJECTIVETo further explore the effects of substance P on the proliferation and apoptosis of fibroblasts obtained from pathological scars in vitro.

METHODSFibroblasts from keloid (KSF) , hypertrophic scar (HSF) and normal dermis (NDF) of 12 burn patients were cultured in vitro and divided into control, SP (with 1 x 10 (-6) mol/L SP added to the culture medium) , and SP + spantide( with 1 x 10 (-6) mol/L SP and 3 x 10 (-5) mol/L spantide added to the culture medium) groups. MTT method or flow cytometry assay was used for the determination of the proliferative activities or apoptotic rate of fibroblasts obtained from KSF, HSF and NDF with SP or Spantide. And then the fibroblasts in SP group were subdivided into 1 x 10( -9) -1 x 10 (-5) mol/L groups to examine the time-or dose-effect of SP to fibroblasts from different sources.

RESULTSIn control group, different types of fibroblasts exhibited similar proliferative activities and apoptotic rates. But there was significant difference in these indices between control and SP group (the proliferative activity of KSF, HSF, NDF was 0. 656+/-0. 071, 0. 525 +/-0. 064, 0. 404+/-0. 063, respectively; and the apoptotic rate of KSF, HSF, NDF was [( 1.5+/-0.3) % , (4.0+/-0.5) % , (5.5+/-0.7) % , respectively],( P < 0. 05). SP had stronger effect on KSF than it did to HSF, as well as it had stronger effect on HSF than it did to NDF. In SP + spantide group, the effect of SP on KSF was partially inhibited, while it was completely inhibited in cultures of HSF and NDF. KSF was more sensitive to SP and the effect was longer when compared with HSF.

CONCLUSIONSP may play an important role in the process of pathological scar formation due to its diverse effects on fibroblasts from different sources.