General Medical Information

Fibroplasia Phase

David J. Terris

Tissue restoration occurs during the period of fibroplasia (proliferation and accumulation of fibroblasts and their products), also known as the proliferative phase. Through a variety of mechanisms, including cytokine activity, fibroblasts are attracted to the wound. These fibroblasts are responsible for the synthesis of the collagen from which the wound derives its strength, and therefore these cells are critical to normal wound healing. The fibroblasts migrate into the wound after approximately 48 to 72 hours and are derived from local undifferentiated mesenchymal cells present in the extravascular tissues. At the same time, endothelial budding occurs (angiogenesis), resulting in newly formed capillaries, which deliver nutrients and oxygen to the wound bed. These abundant capillaries provide the wound with a characteristic beefy-red appearance, known as granulation tissue. This name was coined by early physicians who were impressed with the finely granular nature of the healing surface.

The fibroblasts are very active at this point, producing collagen, mucopolysaccharides, and elastin. The mature scar is comprised primarily of collagen fibers embedded in an extracellular matrix.