Epidermal Growth Factor (EGF) Wound Healing in Fluorocarbon and Chitosan Gels in a Rabbit Model

Abstract

Wound repair follows a general scheme, a sequence of processes taking place in an orderly way: inflammation, repair and closure, remodelling and final healing. Growth factors are produced by the cells aiding the process and are effective during replacement and reconstitution¹. A wound is defined as an interruption of tissue to a greater or lesser extent, which may affect skin, mucosa or organs. The specific sequence of different processes following wounding has one common aim: repair. In every wound type, the healing process runs through three stages, which partly overlap. The first one, the exsudative or inflammatory phase, is followed by the proliferative phase and finally the regenerative phase. Characteristic for the inflammatory phase, lasting approximately 72 h, is the activation of blood coagulation system and the release of various mediators from platelets. This is followed by the coagulation of blood, within 2–4 h inflammatory cell immigration starts and after 32 h fibroblasts are present in the wound site. The second phase of wound repair is characterized by proliferation and lasts from day 1 to a maximum of 14 days. Highly vascularized granulation tissue is formed and angiogenesis and neovascularization in the wound site starts. During the last phase of wound healing the production of new connective tissue is of main importance. If all epidermal layers are effected, re-epithelialization proceeds through the following three stages: migration of basal lamina cells, mitosis of cells migrating across the wound surface and maturation of newly generated cells. The final step in epidermal wound healing is characterized by cell maturation, leading to the regeneration of a defined epidermal layer. Keratinization starts and finally desmosomes promote attachment of cells to one another. The wound is closed and covered by mature epidermis².