MODIFICATION OF THE PROTEOGLYCANS OF RAT INCISOR DENTIN-PREDENTIN DURING IN-VIVO FLUOROSIS

Proteoglycans (PGs) were isolated from the dentin-predentin of fluorot ic and control rat incisor teeth using demineralization in EDTA, follo wed by extraction with 4 M guanidinium chloride in the presence of pro tease inhibitors. Differences in the behaviour of fluorotic and contro l PG were evident during purification by anion exchange chromatography on Q-Sepharose and MONO-Q interfaced with fast protein liquid chromat ography. The PG from fluorotic teeth exhibited a more anionic profile, due to changes in glycosaminoglycan characteristics, since no apparen t differences were evident between the respective core proteins, both of which were 45 kDa. The constituent glycosaminoglycan chains of fluo rotic dentin were of lower molecular size and showed the additional pr esence of dermatan sulfate and heparan sulfate by comparison to non-fl uorotic controls, where only chondroitin-4-sulfate was detected.