ABSTRACT
The basement membrane, as a specialized form of extracellular matrix, is known to influence the development and differentiation of several kinds of organs and tissues. The development of palatal rugae involves morphological changes of oral epithelium, basement membrane (BM), and mesenchymal tissue and, thus, is thought to be one of the model systems of embryonic development. The BM is thought to influence also the rugae development and defferentiation. If so, the components of the BM would change during rugae development. This study was performed to observe the changes of laminin, fibronectin, and collagen type IV in the oral BM during the fetal ages 16~21 by immunohisto-chemistry. The stainability to laminin began to disappear at the anterior portion of the palate on day 17, and at the end of the gestation showed hardly the immunoreactivity to laminin. Along with the decrease of the stainability through the oral apithlium, the BM of rugae area revealed more decreased reactivity to laminin compared to inter-rugal area and such a phenomina could be observed with anterior rugae first and with the middle and posterior rugae thereafter. The stainin pattern of fibronectin was also similar to that of laminin. In case of collagen IV, it maintained the immunoreac-tivity tro collagen IV with a little decrease at the anterior rugae on day 21 of gestation. As was observed, the components of BM, especially the laminin and fibronectin, changed in its immunoreactivity in parallel to the development of the rugae, which enables us to suggest their relationship to the development and differentiation of the rugae.