The subcellular organization of human gingival epithelium cultivated in circumfusion systems

The submicroscopic organization of the emigrating epithelium from two specimens of adult gingiva cultivated in dual-rotary circumfusion systems was investigated. After 21 days, the cultures were fixed and the epithelial outgrowths were embedded and sectioned in planes both vertical and horizontal to the surface of the cover slips for observation by phase-contrast and electron microscopy. Three types of cells were identified: (1) basal-like, (2) prickle-like, and (3) desquamative cells. The basal-like cells were comparatively smaller than the prickle-like cells and were characterized by prominent Golgi complexes, centrioles and scant tonofilaments and desmosomes. The basal-like cells overlaid basal lamina-like structures applied to the surface of the mica cover slips and contained hemidesmosomes. The broad prickle-like cells were characterized by their dense arrays of tonofibrils, increased numbers of desmosomes and microvilli between wide intercellular spaces, several kinds of lysosome-like bodies, and large accumulations of microgranules. Mitochondria with myelin-like figures were frequently encountered in both upper and lower epithelial cells. However, keratohyalin granules were not observed in this study. Desquamative cells had characteristic cytoplasmic condensations on the inner leaflet and contained vesicles of various sizes and shapes. These observations demonstrated that the retention of histiotypic patterns observed in living cells by phase-contrast microscopy was similarly maintained at the ultrastructural level.