Tissue substance P levels in acute experimental burns

Purpose of study To determine the tissue concentrations of substance P (SP) in burns of different depths and to see whether the concentrations of SP relate to the previously reported late increase in tissue histamine concentrations. Materials and methods Experimental animal study with pigs. Superficial, partial thickness and full thickness burns were created and the microdialysis method used to collect samples for substance P analysis from burned and non-burned control tissue during a 24-h follow-up. Results Substance P concentrations increase after 4 h in the partial and full thickness burns reaching the peak at 18 and 12 h, respectively. The increase was later and more modest in the superficial and control sites. At 24 h the SP median concentrations in the superficial, partial and full thickness burns were 28%, 85% and 140% higher than in the control site, respectively. There was a peak in the SP concentration in serum at 4 h followed by a decrease and stabilization at a level about 15 pg/ml. Conclusions The release of substance P in tissue is a possible cause of the late increase in tissue histamine in burns. Medical inhibition of SP is of clinical interest in preventing late histamine liberation in burns.