An Experimental Study Of Biological Effect Of Substance P On Human Hypertrophic Scar-derived Fibroblasts

Hypertrophic scar is very common sequel of human dermal injures especially after burn-wound healing. Though the pathogenesis of hypertrophic scar is still unclear, more and more research show that immunologic and inflammatory reaction may play an important role in the development of HS. Substance P, the first neuropeptide ever found, has been given increasing attention in recent years. Evidences indicate that there are plenty of SP positive nerve fibers in HS, SP is a chemotactic factor for immuno-inflammatory cell and can promote the proliferation and releasing of cytokines of the later. Being the most important functional cell in the wound healing process and the main cell in the HS tissue, fibroblasts play a dominating role in the formation and development of HS. But there is no report about the relationship between SP and HS till now.The objectives of this study are to detect the expression of SP in cultured fibroblasts from HS tissue and explore the effects of SP on the proliferation, collagen metabolism and morphology of fibroblast, then to provider evidences for the accelerating effects of SP in the HS development. Our study is composed of four parts: 1. Immunohistochemistry method was used to detect SP in cultured fibroblasts from HS and normal skin; 2 Cell counting and MTT method were used to study the effects of SP on the proliferation and activity of cultured fibroblasts; 3.Labeled with 3H-proline and SDS-Polyacrylamide Gel Electrophoresis were used to study the effects of SP on the collagenmetabolism of cultured fibroblasts; 4. Light and electron-microscopes were used to study the morphology changes of cultured fibroblasts. The results show that 1. the SP expression in fibroblasts from HS is significantly higher than that from normal skin; 2. the proliferation of fibroblasts is evidently promoted after treated with SP; 3. the CPM of 3H-proline treated with SP is significantly higher than that of control group, and the activity of collagenase is decreased; 4. Morphology changes show that organells activity and cell proliferation were enchanced.Conclusions: 1. the expression of SP in cultured HS fibroblasts is significantly increased and SP may play a role in the formation of HS. 2. the proliferation and activity of fibroblasts is evidently promoted after treated with SP.3. SP can act directly on the collagen metabolism of fibroblasts. Its effects were carried out by two ways: increasing collagen synthesis and decreasing collagen degradation. 4. SP can change the ultrastructure of HS fibroblasts directly and then cause changes on cellular function.