[Observation and analysis of postburn changes in substance P (SP) and SP peptidergic nerve fibers in the intestine of rat].

Substance P (SP) was measured by radioimmunoassay (RIA) and SP peptidergic nerve fibers were identified by Immunohistochemistry (IHC) in the intestinal wall of rats (TBSA 30% and with full-thickness burn) during 72 hours after burn. The results were as follows: (1) SP increased significantly at 1 hr and 4 hr postburn, then decreased markedly 8 hr later, and the low was maintained up to 72 hr. (2) The significant changes in SP peptidergic nerve fibers in the villi after burn were found with immunohistochemical studies including the morphology, distributive densities and SP contents of the SP peptidergic nerve fibers. The results from image analysis showed that the distributive densities of the nerve fibers elevated distinctly in 1 hr group, then dropped at 8 hr and 12 hr and finally elevated again. The results indicated that, the SP release might occur leading to SP consumption in the intestinal wall of rats after burn. It is possible that SP contributes to the postburn intestinal lesion in rats. The SP peptidergic nerve fibers in villus have a direct effect on the damage of intestinal mucosal barrier.