Glycosaminoglycan patterns in gingival proteoglycans of rat with age

Among the potential biochemical indices that are closely associated with craniofacial development are the proteoglycans. Gingival segments from the palate of 4-,6-,8-,12- and 18-week-old rats were incubated for 4 h in medium containing [³H]-glucosamine and [³⁵S]-Na₂SO₄, and subjected to proteoglycan isolation and glycosaminoglycan analysis. Two distinct proteoglycan fractions differing in the degree of sulphation were obtained by ion-exchange chromatography. The incorporation of both labels in the undersulphated fraction increased with age; there was a pronounced decrease with age in the sulphated proteoglycan fraction. The undersulphated proteoglycans showed an age-dependent decrease in hyaluronic acid, and increase in dermatan sulphate and chondroitin 4- and 6-sulphates. Gel filtration of the sulphated proteoglycan fraction yielded high and low molecular-weight proteoglycans, the glycosaminoglycans of which were particularly rich (61-76%) in dermatan sulphate. Smaller quantities of chondroitin 4- and 6-sulphates, and heparan sulphate were also present. All glycosaminoglycans showed a decrease in content with age. The findings suggest a possible correlation between gingival proteoglycan/glycosaminoglycan patterns and development.