Abstract:

Objective To investigate the expression of endothelin-1 (ET-1), angiogenesis and collagen fiber distributions in scars of different stages after burn. Methods Scar samples of different stages after wound healing of burn (early stage, proliferative stage, regressive stage and mature stage, n=8 for each stage) and normal skin tissue samples (normal controls, n=8) were collected. Fibroblasts were isolated and cultured in vitro, and semi-quantitative RT-PCR was employed to detect the expression of ET-1 mRNA in fibroblasts. Angiogenesis in scars was detected by immunohistochemical staining with angiogenesis marker CD34 (percentage of area with CD34 positive cells), and collagen fiber distributions in scars were observed by Masson staining. Results The expression of ET-1 mRNA in fibroblasts increased gradually in the scars of early stage, reached the peak in the proliferative stage, gradually decreased in the regressive stage and recovered to the level of normal controls in the mature stage. The percentages of area with CD34 positive cells of scars of early stage, proliferative stage, regressive stage, mature stage and normal controls were (1.961±0.159)%, (3.432±0.237)%, (0.412±0.026)%, (0.354±0.025)% and (0.1917±0.018)%, respectively, and there were significant differences among scars of different stages and normal controls (P<0.05). It was revealed by Masson staining that the collagen fibers significantly increased in number and densely lined in the proliferative stage of scars. Conclusion In the development and progression of scars after burn, the expression of ET-1 in fibroblasts gradually increases in the early stage, reaches the peak in the proliferative stage, and decreases in the regressive stage, which is well correlated with the changes of angiogenesis and collagen fiber distributions in scars of different stages.

Key words: fibroblast, endothelin-1, angiogenesis, collagen fiber, burn, scar