COX-2 activity and expression pattern during regenerative wound healing of tail in lizard Hemidactylus flaviviridis

Cyclooxygenase-2 (COX-2) is an important mediator of the immune response. It is found upregulated after pathogen invasion or tissue injury and also in many cancers. Of the lesser known functions of this enzyme is its role in effecting epimorphic regeneration. We have previously shown that COX-2 activity is essential for proper regeneration of tail in lizard Hemidactylus flaviviridis; however, the pattern of its activity and expression during the early stages of regeneration was unknown. The present work provides the first report of the trend in COX-2 activity and expression during the wound healing in epimorphic regeneration. It was found in H. flaviviridis that COX-2 gene was induced on the first day after amputation of the tail and expression and activity remained high through the course of wound healing. Further it was revealed that the COX-2 signal was mediated through the PKA/cAMP pathway via binding with the prostaglandin E₂ receptor 2 (EP2). In order to delineate the mechanism of epimorphic regeneration, we must understand the regulation of the major regulatory molecules therein. Therefore, the current study on the role of COX-2 during the regenerative wound healing is of paramount significance. Optimistically, such a mechanistic insight will help us achieve large scale tissue regeneration in humans in the future.