Fig. 4.

Prostaglandin E₂ (PGE₂) production in human gingival fibroblasts (HGF) stimulated with lipopolysaccharide (LPS). (a) HGF stimulated with 1 μg/ml of Actinobacillus actinomycetemcomitans LPS in the presence or absence of 1 μM indomethacin (IND) for 24 h. (b) HGF stimulated with 1 μg/ml of Porphyromonas gingivalis LPS in the presence or absence of 1 μM IND for 24 h. PGE₂ levels in the culture supernatants were measured using enzyme-linked immunosorbent assay. The results are representative of three experiments. (a) *P < 0·05; (b) **P < 0·01.