Effects Of Porphyromonas Gingivalis On Biologic Activity Of Human Umbilical Vein Endothelial Cells

For the past few years, the relation of periodontal disease and cardiovascular disease become growing importance to the people. Epidemiologic survey indicated that it has close correlation between periodontal disease and cardiovascular disease, periodontal disease could be one of risk factors for atherosclerosis, which is a disease that to involve large and medium-sized blood vessel. Today it is generally known that immune reaction and inflammation reaction has particular effect in the development of atherosclerosis. Recently, many studies have manifested that the development mechanism of cardiovascular heart disease(CHD) was closely associated with immune reaction produced by infection. Periodontal disease is the most common infectious disease in human beings. It has been known that the main pathological mechanism of periodontal disease is the local and systemic immune reaction induced by bacteria. Large epidemiologic data also indicated that the incidence of poor oral hygiene and periodontitis in the patients of CHD and peripheral atherosclerosis were higher than average. The basal study has confirmed that interaction among lipopolysaccharide monocyte cytokine(prostaglandin E2, thromboxane A2, interleukin-1β, tumor necrosis factorα, etc)may be the biologic foundation of intercommunication between periodontitis and atherosclerosis. Accordingly, the aim of this study is to observe the effect of Porphysomanas gingivalis on the biologic activity of human umbilical vein endothelial cells and to analyze the change of critical cytokine content of human umbilical vein endothelial cells which incubated with Porphysomanas gingivalis by using cytobiological method. The results may provide evidence of the correlation between CHD and periodontal disease.METHODS:Human umbilical vein endothelial cells were obtained by method of digestion and Porphysomanas gingivalis gained by anaerobic culture method. Proliferation and apotosis of HUVECs infected with Porphysomanas gingivalis were respectively investigated by MTT and apoptosis kit. Scanning electron microscope and transmission electron microscope were taken to observe the effect of Porphysomanas gingivalis on the structure of human umbilical vein endothelial cells. The amount of Interleukin-18 and C-reaction protein production secreted by human umbilical vein endothelial cells cocultured with porphyromonas gingivalis were detected with enzyme–linked immunosorbent assay (ELISA) kit.RESULTS:1. Both P.g and colibacillus LPS inhibited the proliferation of HUVECs, Compared with lipopolysaccharide, P.g showed a higher inhibitition on the proliferation of HUVECs. After HUVECs infected with P.g for 3h, it could be found that the capability of partial cells adhesiveness descend and a few started to desquamate and pyknosis. Along with time lengthening, this effect became more obvious. Apoptosis detection showed that normal group could observe only one or no celluar apoptosis in each high power field after 24 hours, less than 2 percent of apoptosis rate could be calculated in normal group. However, in P.g infected group, smart cellur apoptosis could be observed, cellular average apoptosis rate reaches more than 20 percent. Observing the effect of Porphysomanas gingivalis on human umbilical vein endothelial cells structure by scanning electron microscope and transmission electron microscope, a conclusion was drawn that the pilus of P.g may play important role in the adhesiveness and invasion on endothelial cell through cell phagocytize way .2. HUVECs itselves express small amounts of IL-18 and CRP, P.g dose and time dependently increased the production of IL-18 and CRP in HUVECs. Elevated IL-18 and CRP were found at 4 h, then continued to increase at 8 h, 12 h and 24 h after co-cultivation; under the effect of same concentration, the quantity of CRP was obviously higher than that of IL-18 secreted by HUVECs. P.g ATCC33277 and P.g381 could induced HUVECs secrete IL-18 and CRP, and the quantity are obviously more than control group, but the quantity had no significant difference between P.g ATCC33277 and P.g381.CONCLUSION:P.g obviously inhibited the proliferation of HUVECs and induced cellular apoptosis after it infected HUVECs for over 24h. The pilus of P.g may play important role in invasion through cell phagocytize way. P.g dose and time-depend increased the production of IL-18 and CRP in HUVECs. The results may provide evidence for the effect of P.g on HUVECs and play important role in the pathology of cardiovascular disease.