Abstract
In the basement membrane (BM) of the epithelium and capillary endothelium of the human gingiva, the distribution of anionic proteoglycans was studied ultrastructurally using cationic ferric hydroxide cacodylate colloid (Fe-Cac). In Fe-Cac staining at pH 2.0, iron particles related to the sulfated group of proteoglycans are clearly distributed in the lamina lucida and both surfaces of the lamina densa in the BM both of the gingival epithelium and capillary endothelium. Especially, chain-like arrangements of iron particles bridging between the lamina densa and the cell membrane were observed in the lamina lucida of the BM both of the gingival epithelium and capillary endothelium with Fe-Cac staining at pH 2.0. The ultrastructural distribution of anionic sites at pH 2.0 in the BM of the gingival epithelium and capillary endothelium was closely similar to that of the BM of the renal glomerulus. The lamina densa of the BM of the capillary endothelium was heavily stained with FeCac staining at pH 4.0 related to the carboxylated group of proteoglycans, but that of the gingival epithelium was not. It is possible that there is a common distribution pattern of the anionic sites related to sulfated proteoglycans both in the gingival epithelial and capillary endothelial BM although there are functional differences between their BM.
