Simultaneous blockade of alpha and beta adrenoceptors impairs cutaneous wound healing in rats.

Abstract

BACKGROUND: Recent studies showed that propranolol administration (beta-antagonist), but not phentolamine administration (alpha-antagonist), delays cutaneous wound healing. However, alpha adrenoceptor activation may be participating in propranolol-induced alterations. OBJECTIVE: This study aims to investigate the effects of simultaneous blockade of beta and alpha adrenoceptors on cutaneous wound healing. METHODS: Rats were treated with propranolol plus phentolamine dissolved in water. An excisional lesion was done and measured. Lesions were formalin-fixed and paraffin-embedded 21 days after wounding. Sections were stained with haematoxylin and eosin, toluidine blue and Sirius red, and immunostained for alpha-smooth muscle actin or proliferating cell nuclear antigen. RESULTS: Administration of propranolol plus phentolamine reduced wound contraction and re-epithelialization, but increased cellular proliferation and the number of mast cells. There was no difference in myofibroblast density, collagen fibre organization and polymorphonuclear number between the control and treated groups. CONCLUSION: Simultaneous blockade of beta and alpha adrenoceptors impairs cutaneous wound healing. Furthermore, propranolol-induced impairment on cutaneous wound healing does not occur through alpha adrenoceptor activation.