Ultrastructural study of basal lamina of retinal pigment epithelium.

The ultrastructure of basal lamina (BL) of retinal pigment epithelium (RPE) in guinea pigs was studied by the quick-freezing, deep-etching (QF-DE) method. The retinal tissue was quickly frozen, fractured and deeply etched. A replica was prepared by shadowing with platinum and carbon. Electron micrographs of the BL of RPE provide a three-dimensional (3-D) ultrastructure. The lamina lucida was filled with traversing filamentous structures, which connected the basal infolding of RPE with the lamina densa. The lamina densa consisted of a 3-D meshwork structure. It is suggested that the traversing filamentous structures in the lamina lucida might play a role in anchoring the basal infolding of RPE and in maintaining the normal architecture.