烫伤大鼠创面皮肤中神经肽P物质的变化

目的　观察皮肤创面神经肽P物质 (SP)的变化规律并探讨其来源。　 方法　运用免疫组化检测烫伤大鼠皮肤创面、创周和远处未损伤皮肤内含SP的神经分布密度的改变及其神经肽的分布 ,运用原位杂交技术观察其mRNA表达情况。　结果　烫伤后 15min在皮肤创面、创周和远处未损伤皮肤含SP的神经分布密度明显下降 (P <0.0 5 ),烫伤后 6～ 12h达到最低值 ,以后逐渐恢复。相比之下 ,在创周恢复过程中SP出现较早 ;在创面和创周的真皮层 ,SP免疫反应阳性的的巨噬细胞样大细胞从局部血管中游出 ,烫伤后 12h该细胞与局部含SP的神经关系密切 ,伤后 2 4h该细胞染色增强、破碎并释放大量SP免疫反应阳性的颗粒状物质 ,而后这些细胞在烫伤后 4 8h消失。原位杂交结果显示 ,伤后 6h相同大小细胞内表达编码合成P物质前体的前速激肽A(PPTA)mRNA。　 结论　皮肤烧伤后 ,SP不仅从皮肤内神经末梢释放 ,也可能从局部炎性细胞合成释放

An experimental study on the change in neuropeptide substance P in the burn wound skin in scalded rats

Objective To investigate the change in neuropeptide substance P (SP) in the burn wound skin in scalded rats. Methods The SP distribution density in the rat skin samples from the burn wound, peri-wound area and remote area of scalded rats were determined by immunohistochemistry technique. The mRNA expression of SP was observed by in situ hybridization. Results The distribution density of SP in the skin samples from the above three areas decreased obviously since 15 mins postburn , dropped to the lowest level during 6-12 postburn hou (PBH), and then recovered thereafter. Comparatively, the recovery in peri-wound area occurred earlier. In addition, there was emigration of macrophage-like large cells with positive SP immunoreactivity from local blood vessels in the dermal layer of the burn wound and peri-wound areas. The large cells were closely related to the local SP-containing nerve fibres at 12 PBHs. Intensified staining of the cells was identified at 24 PBHs with the disintegration of the cells into pieces with release of large amounts of positive SP immunoreactive granules, followed by disappearance of the cells at 48 PBHs. It was indicated by in situ hybridization that the preprotachykinin A (PPTA) mRNA encoding and synthesizing SP was expressed in various cells at 6 PBHs. Conclusion SP might be synthesized and released from cutaneous nerve ending or from local inflammatory cells after skin burn injury.