The Effects Of Substance P On Intrinsic Growth Factors And Their Receptors Of Cultured Rat Granulation Tissue Fibroblasts In Vitro

Wound healing is a complex process in which fibroblasts, one of the main components in granulation tissue, have an important effect on it. As known, growth factors, autocrine or paracrine from repairing cells, participate in the regulation of wound healing and Substance P(SP), one neuropeptide released from thinly myelinated Aδ pain fibers and unmyelinated C fibers, actively takes part in the regulation on repairing cells proliferation and scar tissue formation.Our earlier studys in vivo showed that SP could promote wound healing and this effect may be fulfilled through regulating repairing cells intrinsic growth factors and receptors expressions. In order to confirm this suspect, we choosed a cultured rat granulation tissue fibroblasts model in vitro and applied RT-PCR and cell-ELISA technology to detect the changes of firbroblasts intrinsic EGF, bFGF, TGFβ-1 with their receptors gene expressions and protein synthesises after stimulated by SP. Our purpose was to explore the possible effects and patterns imposed by SP on fibroblasts intrinsic growth factors and their receptors expressions, which maybe offer theoretical basis for promoting wound healing via improving nervous functions and regulating neuropeptides secretions.Our results showed: [1] At gene level, the effects imposed by SP on fibroblasts intrinsic EGF, bFGF and TGFβ-1/R-1/R-2 expressions, displayed a two-way distribution. From lower concentration (10-9M), SP up-regulated EGF, bFGF, TGFβ-1/R-1/R-2 gene expressions gradually, after optimal concentrations (10-8M-10-7M), its role diminished less and less at higher concentrations. But SP could promote EGFR, FGFR-1 gene expressions only athigher concentrations (10-6M-10-5M) and no effects were observed at lower concentrations (10-9M-10-7M). More addition, the peak time points (3h-6h) of SP's effects on EGF, bFGF, TGFβ-1/ R-1 gene expressions were prior to that of EGFR, FGFR-1 and TGFR-2 (12h). [2] At protein level, the concentrtion-effect curve and optimal concentrations of SP's effects on fibroblasts intrinsic growth factors protein synthesizes were similar to and its peak time points (16h-36h) were later to that at gene level.Our results indicated that SP could directly affect fibroblasts intrinsic growth factors and their receptors gene expressions and protein synthesizes and its role patterns were correlated with the kinds of growth factors and their receptors and also with SP's acting concentrations and times. Analysising with others researches, we deduced that these effects maybe derived from their signal transduction cross-points between SP and growth factors and also related to arachidonic acid metabolitea and pro-conogenes activations in cells. All of above suggested the effects imposed by SP on fibroblasts intrinsic growth factors and their receptors maybe the cellular biological mechanisms about the roles of SP in promoting fibroblasts proliferation, wound healing and scar tissue formation.