Endogenous production of heparin-binding EGF-like growth factor during murine partial-thickness burn wound healing

Heparin-binding EGF-like growth factor (HB-EGF), a potent epithelial cell mitogen, has been identified in human burn blister fluid and excised human burn wounds. Topical application of HB-EGF to murine partial-thickness scald burns accelerated reepithelialization, increased keratinocyte proliferation, and enhanced production of endogenous transforming growth factor-α in the healing wounds. The goal of the present study was to examine the production of endogenous HB-EGF and transforming growth factor-alpha (TGF-α) in a murine partial-thickness scald burn model. Keratinocyte proliferation was assessed by 5-bromo-deoxyuridine incorporation, and tissue sections were examined by in situ hybridization for HB-EGF mRNA expression and by immunohistochemistry for HB-EGF and TGF-α production. HB-EGF mRNA expression and production of HB-EGF and TGF-α proteins by both marginal surface keratinocytes and hair follicle epithelial cells reached a maximum by postburn day five and decreased thereafter. This corresponded to the peak period of keratinocyte proliferation. We conclude that HB-EGF and TGF-α act in conjunction to stimulate wound healing following thermal injury.