Effect of lipopolysaccharide on proteoglycan synthesis by adult human gingival fibroblasts in vitro.

The effect of lipopolysaccharide preparations from Salmonella enteritidis, Bacteroides gingivalis, and Actinobacillus actinomycetemcomitans on human gingival fibroblasts was studied. Lipopolysaccharide from all sources inhibited fibroblast proliferation in the concentration range of 0.5 to 50 micrograms/ml, with the lipopolysaccharide from A. actinomycetemcomitans having the strongest inhibitory effect. Assessment of the effect of lipopolysaccharide on gingival fibroblast metabolism indicated both total protein and proteoglycan synthesis to be inhibited with increasing concentrations of lipopolysaccharide. As for the antiproliferative effect, lipopolysaccharide from A. actinomycetemcomitans had the greatest inhibitory effect on cell synthetic activity. This inhibitory effect was determined by pulse-chase experiments to be a true depression in synthesis. Furthermore, the effect was independent of lipopolysaccharide-induced changes in cell proliferation and prostaglandin synthesis. This study confirmed the toxic effect of lipopolysaccharide on fibroblasts and, in particular, indicated that various lipopolysaccharide preparations vary in their potency to influence cell proliferation and extracellular matrix synthesis.