Abstract:

Objective To quantify the interleukin（IL）-1β mRNA and IL-6 mRNA expression induced by lipopolysaccharides（LPS） extracted from Porphyromonas endodontalis（P.endodontalis） in osteoblasts, and to relate P. endodontalis LPS to the bone resorptive pathogenesis in the lesions of chronic apical periodontitis. Methods MG63 cells was pretreated with PD98059 or SB203580 for 1 h and then treated with P.endodontalis LPS for 6 h. The expression of IL-1β mRNA and IL-6 mRNA were detected by reverse transcription polymerase chain reaction（RTPCR） technique. Results The production of IL-1β mRNA induced by P.endodontalis LPS decreased in osteoblasts pretreated with PD98059. Both of the production of IL-1β mRNA and IL-6 mRNA induced by P.endodontalis LPS decreased in osteoblasts pretreated with SB203580. Conclusion The synthesis of IL-1β mRNA stimulated by P.endodontalis LPS in MG63 probably occur via extracellular signal-regulated kinase（ERK） 1/2 and p38 mitogen activated protein kinase（MAPK） signal transduction system. The synthesis of IL-6 mRNA stimulated by P.endodontalis LPS in MG63 probably occur via p38MAPK signal transduction system.

Key words: Porphyromonas endodontalis, lipopolysaccharides, osteoblasts, extracellular signal-regulated kinase 1/2, p38 mitogen activated protein kinase