Role of vasoactive intestinal polypeptide in burn-induced oedema formation

Vasoactive intestinal polypeptide has been demonstrated to lack inherent ef fects on capillary permeability, but also to potentiate the oedema promotin g actions of other inflammatory mediators or even to strongly reduce organ damage and subsequent oedema in ischemic models of the lung and heart. This study investigated the role of VIP on oedema in partial- and full-thicknes s skin burns of anaesthetised rats in vivo by spectrophotometrical quantifi cation of Evans blue albumin. Results show that systemic VIP elicited a sig nificant drop in mean arterial blood pressure versus saline (p < 0.001) and VIP antiserum (p < 0.001) both in burned and non-burned animals. VIP also decreased heart rate versus saline (p < 0.05) and anti-VIP (p;< 0.01) in no n-burned and burned animals. EB-albumin in normal skin was significantly in hibited by VIP as compared to saline (p < 0.05), but did not differ signifi cantly from VIP-antiserum. A significant inhibition of EB-albumin extravasa tion versus saline was also seen following administration of VIP-antiserum (p < 0.01). Similarly, VIP significantly reduced EB-albumin extravasation v ersus saline treatment in partial-thickness (p < 0.01) and full-thickness b urns (p < 0.001), while VIP-antiserum had no significant effect on skin per fusion in any of the burned groups as compared to saline treatment. The pre sent results show that systemic VIP is a potent inhibitor of burn oedema. T his effect could be secondary to constriction of skin vessels as a result o f VIP-induced systemic hypotension or be mediated by the interaction of VIP with other oedema promoting mediators released following a thermal trauma to the skin. (C) 2000 Elsevier Science Ltd and ISBI. All rights reserved.