Effect of in vitro aging on Campylobacter rectus lipopolysaccharide-stimulated PGE2 release from human gingival fibroblasts

Abstract

OBJECTIVE: We examined the influence of in vitro aging on Campylobacter rectus (C. rectus) lipopolysaccharide (LPS)‐stimulated prostaglandin (PG) E₂ release from human gingival fibroblasts (HGFs). MATERIALS AND METHODS: LPS was prepared from C. rectus ATCC33238. HGFs were established from healthy gingival tissue removed from three patients (donors A, B and C), aged 10–12 years. Aging of the cells in culture was determined with increasing population doubling. The cells were cultured until confluence, then stimulated with LPS (1.0 μg ml^‐1), and the levels of PGE₂ in the medium were measured after 24 h by radioimmunoassay. RESULTS: The LPS‐stimulated PGE₂ production in each old cell (passage 17–20) was significantly increased to about 1.6–2.6 times than that in the corresponding young cells (passage 5–6). The gene expression of cyclooxygenase‐2 mRNA in the old cells was higher than that in the young cells in response to LPS. In the absence of LPS, PGE, production levels in both the young and old cells were very low, and also at the same level. However, there was a higher level of LPS‐stimulated PGE₂ production in the young cells from donor C compared to that in the old cells from donor B. The LPS‐stimulated PGE₂ production in each young cell from donors A and C was almost equal to that in each old cell from donors B and A, respectively. CONCLUSIONS: The results suggested that aging in HGFs may be one of the factors that take part in the stimulation of C. rectus LPS‐stimulated PGE₂ production in old cells.