Mucopolysaccharide localization in gingival epithelium

Abstract

Short incubations, at 37°C, of small freshly excised pieces of healthy human gingivae iancorporated [35S]‐sulphate and [3H]‐acetate into macromolecular material which could be precipitated intercellularly in the epithelium. Following radioactively pulse‐chased incubations, such localization was observed by autoradiography on cryostat histological sections fixed in cetylpyridinium chloride. Critical electrolyte salt concentration elution indicated that most of the intercellular material was soluble in 0.63M‐MgCl2, and any material which remained was intracellular. In vitro and in vivo incorporation studies were compared. These data corroborate biochemical studies (Wiebkin, Bartold & Thonard 1979) together with other histochemical observations that proteoglycans (mucopolysaccharides) are a major intercellular component of human gingival epithelium. Molecular conformation and the relatively rapid synthesis and secretion rate for this class of epithelial macromolecule may explain the lack of susceptibility of this material in the intercellular site, both to degradation by some specific enzymes previously reported and to elution with critical salt concentrations from cationic detergent precipitates. The method described, together with in vivo incorporation studies, provides a useful technique for studying direct effects of some microenvironmental influences on gingival epithelium.

Proteoglycans from adult human gingival epithelium

“…The presence of oral bacterial or tissue enzymes acting on the substrate in the intercellular location has been suggested as a possible factor in the aetiology of periodontal disease (Thonard & Scherp, 1962). Studies on suspension and monolayer cultures of either gingival or amniotic epithelium indicated that cell aggregation correlated positively with the degree of sulphation of intercellular proteoglycan and that the hyaluronic acid synthesis was limited in cultures where cell/cell contact was minimal (Wiebkin & Thonard, 1969). Radioactively labelled macromolecular material extracted from small pieces of gingivae (predominantly epithelium) under dissociative conditions was chromatographed on Sepharose 2B-CL with 0.5 M-sodium acetate.…”

Mucopolysaccharide localization in gingival epithelium Factors affecting biosynthesis of sulphated proteoglycans in organ cultures of gingival epithelium

“…Control sections ofhuman gingivae which had been incubated at 37 ^^C for 15 min with radioactive precursor followed by 60 min in radioactive isotope free medium demonstrated localization of incorporated label in the intercellular material of the epithelium (Fig. 2) particularly in the Stratum spinosum (Wiebkin & Thonard 1981a).…”

“…Biochemical quantitation and microscopic localization of macromoleeular uronates, synthesized in amnion cell lines (Thonard & Wiebkin 1973), in primary cultures of gingival epithelial cells (Wiebkin ei al. 1980), in short term incubations of gingival pieces (Wiebkin & Thonard 1981a), and in whole gingival pieces {Thonard & Scherp 1962) indicate that epithelial cells are capable of synthesizing proteoglycans. These macromolecular uronatccontain substantial sulphate (Wiebkin, BartoU' c'l Thonard 1979, Bartoid, Wiebkin & Thonard 1981, hexosamine, associated protein, some galaciose, and xylose.…”

Cell responses to Hydron by a new in‐vitro method

“…'H-thymidine {Simnett 1975) by replicating cells and "S-sulphate into intercellular matrix proteoglycan (Thonard & Wiebkin 1973. Ulreich & Chvapil 1981. Wiebkin & Thonard 1981).…”