IMMUNOCHEMICAL DETECTION OF THE PROTEOGLYCANS DECORIN AND BIGLYCAN INHUMAN GINGIVAL CREVICULAR FLUID FROM SITES OF ADVANCED PERIODONTITIS

This study characterized proteoglycan metabolites present in gingival crevicular fluid (GCF) collected from sites with clinical evidence of advanced periodontal disease. The metabolites were purified by anion-e xchange chromatography from which a chondroitin sulphate rich fraction was identified by cellulose acetate electrophoresis. Sodium dodecylsu lphate-polyacrylamide gel electrophoresis of this fraction revealed a broad silver-staining band with mel. wt 55-65 k and Western blotting s uggested that this band was immunoreactive with CS-56, a monoclonal an tibody for chondroitin sulphate. Digestion of the metabolite with chon droitinase ABC (protease-free) led to the loss of the silver-staining band. Dot-blot analysis identified components in this fraction that we re immunoreactive for the monoclonal/polyclonal antibodies against the C-termino of decorin and biglycan. Amino acid analysis revealed the c omposition of the proteoglycan metabolite to be rich in glycine, serin e and glutamic acid. Immunochemical and biochemical analyses were comp ared with those of proteoglycan purified from human alveolar bone. Cha nges in the amino acid composition were noted, suggesting the proteogl ycan metabolite has undergone extensive modification and fragmentation to the protein core. The results suggest that the proteoglycan metabo lite from GCF represented a degradation product originating from the a ctive destruction of the alveolar bone. They provide further support f or the proposal that the appearance of proteoglycan metabolites in GCF is a biomarker for active destruction of alveolar bone, the biochemic al analysis of which provides important information on mechanisms invo lved in the pathology of periodontal diseases. (C) 1998 Elsevier Scien ce Ltd. All rights reserved.