The life cycle of the myofibroblast

Myofibroblasts in pig granulating wounds have an identifiable life cycle that parallels the eight week span of contraction of the wounds. As seen by electron microscopy, fibroblasts with a contractile appearance became prominent within one week after wounding and persisted for 12 weeks, after which time they were not visible. Large tangled filaments, measuring 120 Angstrom units are prominent in fibroblasts in late contracted wounds and may be actin. Such filaments could preserve fibroblasts in a contracted state and allow time for the reorganization of collagen into a fixed rigid scar.