Effect of lipopolysaccharide from Porphyromonas gingivalis on prostaglandin E2 and interleukin-1β release from rat periosteal and human gingival fibroblasts in vitro

Lipopolysaccharide (LPS) was extracted from Porphyromonas gingivalis (W83) by the Westphal procedure, nuclease-digested and ultracentrifuged. Fibroblasts were obtained from human gingival tissue and rat periosteum, grown to confluence then stimulated in serum-free medium with 0.1, 1.0 and 10.0μg/ml LPS. The levels of prostaglandin E₂ (PGE₂) and interleukin-1β (IL-1β) released were measured after 2, 4 and 6 d by specific radioimmunoassays. Unstimulated gingival fibroblasts produced low levels of PGE₂ (24.5 ± 1.5 (SD) ng/ml) and IL-1β (0.34 ± 0.29 ng/ml). LPS stimulated statistically significant dose-related increases hi PGE₂ and IL-1β at the concentrations of LPS tested. At 10.0μg/ml, LPS-stimulated fibroblasts produced 363.5 ± 40.3 ng/ml PGE, and 1.81±0.1 ng/ml IL-1β in 6 d. These results demonstrate that LPS from P. gingivalis is capable of stimulating PGE, and IL-1β release from fibroblasts. This would appear to be an additional mechanism by which LPS can induce tissue breakdown in periodontal disease.