Effects of root canal sealers on lipopolysaccharide-induced expression of cyclooxygenase-2 mrna in murine macrophage cells.

Cyclooxygenase-2 (COX-2) is a useful biomarker of the inflammatory potential of biomaterials in vitro. In this study we investigate the effects of soluble extracts from 3 selected root canal sealers (AH26, Sealapex, and N2 Universal) on COX-2 mRNA expression in cultured murine macrophage cells. Root canal sealers and the addition of lipopolysaccharide (LPS) both produced significant increases in COX-2 mRNA expression in RAW 264.7 macrophages. In addition, both Sealapex and N2 Universal produced a synergistic 6- to 8-fold increase in COX-2 mRNA expression, whereas AH26 did not demonstrate synergy with LPS. These results suggest that LPS and certain root canal sealers have a synergistic effect on the inflammatory responses of macrophages. Under the conditions of this in vitro study, the results suggest that one potential mechanism of periapical inflammatory reactions might be the synergistic effects of certain root canal sealers on LPS-induced COX-2 expression by macrophage cells.