Cyclooxygenase-2 Inhibitors Decrease Interleukin-1β-Stimulated Prostaglandin E₂ and IL-6 Production by Human Gingival...

Previous work showed that normal and aggressive periodontitis (AgP) gingival fibroblasts produce the boneresorbing cytokine IL-6. PGE₂ is important in regulating IL-6 production. Non-steroidal anti-inflammatory drugs inhibit PG synthesis via COX-1 and/or COX-2 isoenzymes and may inhibit periodontal destruction. COX-2 is induced after cellular activation (i.e., by inflammatory cytokines such as IL-1β). Little is known about IL-1β-stimulated AgP fibroblast IL-6 and PGE₂ production and their regulation by COX inhibitors. The objective of this study was to determine the effects of COX-2 inhibitors on amounts of PGE₂ and IL-6 made by IL-1β-stimulated gingival fibroblasts.

Gingival fibroblasts (2.5 × 10⁴ ) from healthy or severe periodontitis patients were cultured in serum-free medium, with or without IL-1β (10^-11 M) for 24 hours, with or without the COX-1/2 inhibitor indomethacin or the selective COX-2 inhibitors NS-398, celecoxib, or rofecoxib. PGE₂ and IL-6 in culture supernatants were determined by specific enzyme-linked immunosorbent assay (ELISA)s.

All of the COX inhibitors caused dose-dependent decreases in IL-1β-stimulated PGE₂ , to a maximum of >90% in all cell lines (P ≤0.0001). The selective COX-2 inhibitors, but not indomethacin, caused partial (generally up to approximately 60%), dose-dependent decreases in IL-1β-stimulated IL-6 in all cell lines (P ≤0.003). When exogenous PGE₂ was added concurrently with COX-2 inhibitors before addition of IL-1β, IL-6 production returned to levels at or approaching that produced by cells exposed only to IL-1β (P ≤0.04).

The results suggest that COX-2 inhibition may be useful in helping to control fibroblast production of IL-6 in patients with severe periodontitis. J Periodontol 2003;74:1754-1763.