Wound contraction decreases with intravenously injected substance P in rabbits

Substance P is an injury-inducible endogenous factor for the mobilization of CD29+ stromal-like cells into circulation and that are major effectors of accelerated healing. In this study, we evaluated the effect of intravenously injected substance P on full-thickness skin wound healing as a secondary intention wound model. We made circular full-thickness skin wounds on the ears of 28 New Zealand white rabbits. They were treated with phosphate-buffered saline, or intravenous 5, 50, or 250 n mole/kg substance P at days 0 and 1. All substance P-treated groups showed a 2.6-5.4-fold higher CD29 expression and resulted in greatly decreased wound contraction and early maturation of the stroma. However, a significant decrease in wound contraction was measured only in the 5 n mole/kg treatment group. We conclude that intravenously injected substance P at 5 n mole/kg decreases wound contraction and promotes wound maturation in full-thickness skin wounds in a rabbit ear model.