ABSTRACT
Inflammatory response phase (Figure 8.1) Wound healing starts with clot formation. Platelets adhere to the wound edges and release several important cytokines including platelet-derived growth factor (PDGF) and endothelial growth factor (EGF). These attract macrophages and neutrophils, which release further cytokines, amplifying the process. Serotonin (released from platelets) and histamine (released from mast cells) increase vascular permeability and allow neutrophils and macrophages into the wound. Within a few hours, the wound is occupied by an amorphous collection of white and red blood cells, plasma, coagulation proteins, fibrin and fibronectin. This mass supports the wound until collagen can be laid down. Macrophages play an essential role in wound healing by phagocytosis of bacteria and dead tissues and by secreting growth factors.
