Cyclooxygenase-1-Coupled Prostaglandin Biosynthesis Constitutes an Essential Prerequisite for Skin Repair

This investigation demonstrated a functional coupling between cyclooxygenase-1 (cox) and prostaglandin E₂/D₂ biosynthesis in murine skin repair. Cyclooxygenase-1 expression decreased transiently after excisional wounding, and this was followed by a marked fall in the rate of prostaglandin E₂/D₂ biosynthesis at the wound site. Expression of cyclooxygenase-1, prostaglandin synthases, and prostaglandin E₂/D₂ production were colocalized in new tissue at the margin of the wound. Although cyclooxygenase-2 expression was strongly induced in granulation tissue on injury, this isoform did not contribute to high prostaglandin E₂/D₂ concentrations in wounds. Accordingly, wound tissue from SC-560-treated mice (selective cyclooxygenase-1 inhibitor) and diclofenac-treated mice (nonselective cyclooxygenase inhibitor), but not celecoxib-treated mice (selective cyclooxygenase-2 inhibitor), and wound tissue from cyclooxygenase-1-deficient animals exhibited a severe loss of prostaglandin E₂/D₂ at the wound site, and this change was associated with an impairment in the normal wound morphology. Topically administered prostaglandin E₂ (dinoprostone) was able to restore normal wound repair to diclofenac-treated mice. In contrast to the presence of an injury-induced cyclooxygenase-2, these data constitute strong evidence that cyclooxygenase-1-coupled prostaglandin E₂/D₂ biosynthesis has a central role in skin repair.