In order to identify wound contraction and scar formation during palatal mu
coperiosteal wound healing in growing rats, the temporal and spatial distri
bution of myofibroblasts and matrix components were determined immunohistoc
hemically. Myofibroblasts were found in the mucosal part of the palatal wou
nd tissue between 4 and 22 days, with the highest density at 8 days post-wo
unding. The number of collagen type I and type III fibers gradually increas
ed until about 8 days post-wounding, and thereafter the staining intensity
of collagen type III decreased. At 60 days post-wounding there were more tr
ansversely oriented collagen type I fibers and less type III fibers and ela
stin present in the submucosa than in normal tissue. The results suggest th
at in this model wound contraction mainly takes place: in the mucosa betwee
n 4 and 22 days post-wounding. Furthermore, palatal wounds made in young ra
ts heal with distinct scar tissue formation. Therefore, this model is usefu
l to test the effects of therapies that aim to reduce wound contraction and
scarring after cleft palate surgery.