Fibroplasia typically begins a few days after an injury. It is initiated by the migration and proliferation of fibroblasts, which are stimulated by various growth factors such as platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-β), and fibroblast growth factor (FGF). These growth factors are released by platelets, macrophages, and other cells involved in the inflammatory phase of wound healing.
