OBJECTIVETo observe the effect of Porphyromonas gingivalis (Pg) on the production of nitric oxide (NO) in cultured human umbilical vein endothelial cells (HUVEC), and to investigate the pathway of damaging endothelial function by Pg.

METHODSPg ATCC33277 was cultured in anaerobic jar, and HUVEC was treated with various concentrations of Pg ATCC33277 at multiplicity of infection (MOI) of 1:10, 1:100 and 1:1000 for 4, 8, 12, 24 h respectively. The cells supernatants were collected and stored at -70 degrees C and NO concentration in the cells supernatants was measured by nitrate reductase assay.

RESULTSWithin 24 h, Pg at MOI of 1:10 and 1:100 stimulated the release of nitric oxide in cultured HUVEC. Within 12 h, Pg at an MOI of 1:1000 group increased NO production, and NO decreased at 24 h.

CONCLUSIONSPg has an effect on the production of NO. Low concentrations of Pg stimulated release of nitric oxide in endothelial cells but high concentrations can decrease the release of NO.