The reinnervation pattern of wounds and scars may explain their sensory symptoms

Anaesthesia, pruritis and pain are common in cutaneous scars. The reinnervation pattern of heating wounds and scars might help to explain these symptoms, as sensory neurotransmitters are known to be mediators of inflammation and heating. We quantified the regeneration patterns of blood vessels and nerves in excisional. skin wounds as they matured into scars. Mice underwent 1 cm(2) full thickness skin excisions. Wounds were harvested between five and 84 days. Sections underwent immunohistochemical staining for protein gene product 9.5 (Pi a pan-neuronal marker, and the sensory neuropeptides calcitonin gene related peptide (CGRP) and substance P (SP). The endothetial marker von Willebrand factor (VWF) was used to allow co-localisation and quantification of blood vessels. Nerve fibre density was quantified at multiple sites within wounds. There was no difference in the reinnervation / revascularisation pattern between peripheral and central sites. The density of PGP9.5, CGRP, SP and VWF peaked between 14 and 42 days, and levels of PGP9.5, CGRP and VWF all decreased to approximately those found in unwounded skin by 84 days (mature scar). SP levels, however, remained elevated at approximately twice the density found in unwounded skin. Increased densities of SP and CGRP in heating wounds could explain the unpleasant sensory symptoms of heating wounds. (C) 2006 The British Association of Plastic Surgeons. Published by Elsevier Ltd. All rights reserved.