OBJECTIVETo investigate the influence of substance P (SP) on the release of histamine in the human hypertrophic scar tissue, and to explore the prerequisite of their interaction.

METHODSTissue specimens of normal skin and hypertrophic scar from eight hospitalized patients were excised and cut into 0.5 to 1.0 mm3 pieces, and the histamine release by mast cell (MC) under the stimulation of different concentration of SP and calcium, as well as the different affect time of SP, were determined with fluorescence spectrometer. Then the histamine release rate was calculated.

RESULTSThere was obvious release of histamine when SP concentration was 1 x 10(-6) mol/L , and the release rate was (50.0 +/- 3.6) %, which was significantly higher than that by SP in the concentration of 0 mol/L [(44.0 +/- 3.2) %, P < 0.01]. Therefore it seemed to be dose-dependent. About 90% of histamine was released within 15 minutes of 5 x 10(-1) mol/L Substance P stimulation, and it was also time-dependent. The histamine release reached the peak when calcium concentration was 5 x 10(-3) mol/L, which seemed to be dose-dependent, but it decreased transiently when calcium concentration was 1 x 10(-3) mol/L. In all occasions, the influence of SP on the histamine release by MC in hypertrophic scar (HS) was markedly higher than that in normal skin (NS) (P < 0.01). Conclusion The influence of SP on the histamine release by MC in HS was markedly higher than that in NS, and it might be closely related to itching sensation and the formation of hypertrophic scar.