Myofibroblasts in healing palatal wounds of the beagle dog.

Excisional wounds were inflicted on the palatal mucoperiosteum of beagle pups at intervals from 3 to 31 days before the animals were killed, when the animals were perfused and the tissue examined by electron, microscopy. Fibroblasts with the morphological characteristics of myofibroblasts, including bundles of intracellular filaments, intercellular junctions and an initmate association with adjacent connective tissue fibrils, were observed in wounds at all intervals after 3 days. These cells were most numerous 10-15 days after wounding especially in the periosteal region. This distribution closely resembles that obtained after immunochemical staining for actin and suggests that the cells observed by electron microscopy may have contractile properties and be responsible for the contraction that is evident in the healing palatal wound.