Incubation of human oral mucosa in physiological solutions containing proteolytic enzymes permits separation of the preparation into its epithelial and connective tissue components. Trypsin, collagenase and elastase were utilized to effect epithelium-connective tissue separation. Elastase was the most suitable in that a reliable separation of the epithelium from the connective tissue occurred at the lamina lucida (the electron-lucent zone between the basal cell and basal lamina) with only minimal alteration of the epithelium. The most common change observed in separated epithelium was the formation of cytoplasmic protrusions or blebs on the inferior surface of the epithelial basal cell. Bleb formation was quite extensive when preparations were incubated one to two hours beyond the point where the epithelium could be separated from the connective tissue. With prolonged incubations inferior aspects of epithelial basal cells demonstrated the formation of an entirely new cytoplasmic front apparently resulting from fusion of membranes and subsequent confluence of the cytoplasm contained within the blebs. Individual hemidesmosomes or small lengths of the original inferior epithelial basal cell membrane became enclosed in membrane-bound vacuoles within the cytoplasm of the epithelial basal cell. These vacuoles were shown to have been interiorized by the absence of a ruthenium red reaction product within the vacuolar spaces. Bleb formation was shown to be strictly enzyme-induced since intact specimens demonstrated extensive basal cell blebbing following prolonged incubation. Occasional desmosomes were broken and the component halves interiorized in membrane-bound vacuoles within the cell cytoplasm. Alterations observed in epithelial basal cells as a consequence of exposure to exogenous proteolytic enzymes mimic alterations observed in many disease processes and during certain stages of development.The junction of stratified squamous epithelium with the underlying connective tissue occurs at the basal lamina. The basal lamina is currently thought to be, in large part, the product of the epithelium (Briggaman et al., '71; Hay and Dodson, '73). The tenacious attachment (Jakus, '54; Charles and Smiddy, '57; Kenyon, '69) of mammalian stratified squamous epithelium to the connective tissue appears to be effected by hemidesmosomes located on the inferior aspect of the epithelial basal cell (Stern, '65 Incubation of stratified squamous epithelium-connective tissue samples in solutions containing proteolytic enzymes is another method which permits the epithelium to be separated from the connective tissue. Neiders and Weiss ('70) have reviewed enzymatic methods for separating skin and oral mucosal stratified squamous epithelium from the underlying connective tissue. In this study we report the ultrastructural changes observed i n human oral mucosal epithelium and the subjacent connective tissue following incubation in physjolxical solutions which contained proteolytic enzymes. This study was undertaken for two reasons. ( 1...
