Objectives: To explore the destructive mechanism of P.gingivalis on periodontium and to better understand the pathogenic effects of P.gingivalis fimbriae. Methods:Western blotting was used to detect the degradation effects of P.gingivalis ATCC 33277 and its fimA-deficient mutant on focal adhesion components paxillin and focal adhesion kinase (FAK) of Hela cells and immortalized gingival epithelial cells (IHGE cells). Results:P.gingivalis ATCC 33277 wild strain and its fimA-deficient mutant induced degradation of paxillin and FAK both in Hela cells and in IHGE cells. fimA-deficient mutant had a remarkable weaker degradation ability than the wild strain. In IHGE cells, paxillin and FAK were degraded in a time-and MOI-dependent manner. Conclusion:P.gingivalis fimbriae-mediated adhesion and invasion to epithelial cells may promote the degradation of focal adhesion components. IHGE cells may be more suitable for the study of periodontal pathogens than Hela cells.

Objective:To study the effects of green-tea polyphenol, (epigallocatechin gallate,EGCg) on the cellular inflammatory responses of gingival epithelial cells. In order to find out a safe and efficient inflammation-inhibitor for periodontitis prevention and treatment. Methods:A model of cellular inflammatory responses of gingival epithelial cells stimulated by Porphyromonas gingivalis vesicles in vitro was established. The effects of EGCg on PGE2 production of gingival epithelial cells was detected by ELISA. Further more, the effects of EGCg on COX (cyclooxygenase)-2 and MMP (matrix metalloproteinase)-3 mRNA expression were determined by Real-time RT-PCR. Results:EGCg dose-dependently inhibited PGE2 production and COX-2, MMP-3 mRNA expressions. Conclusion:EGCg has inhibitory effects on cellular inflammatory responses of gingival epithelial cells and possesses the potentiality to be a periodontal inflammation-inhibitor.

Objective:To investigate the effects of serum from smoking individuals with periodontitis in the process of Fusobocterium.Nucleatum(Fn)invading KB cells and the expression of matrixmetalloproteinase1(MMP1)of KB cells.Methods:Serum was prepared from 10 smokers with periodontitis(group Y),10 nonsmokers with periodontitis(group N)and 5 periodontal healthy nonsmokers(group H).Serum of 200,400 and 800 μl from the subjects was added to the model of Fn invading KB cells respectively and cultured for 24 hours,the cfu of cellinvaded bacteria was estimated by colony counting.MMP1 protein level in culture supernatant wasmeasured by ELISA.Results:In the 800 μl serum groups,the percentage of invaded cfu was 12.59 ±1.27,8.03 ±0.075 and 7.99±0.14 in group Y,N and H(P ＜0.05)respectively,the concentration(μg/L)of MMP1 in the cultrue supernatant of group Y,Nand H was 400.04 ±21.02,252.57 ±18.89 and 262.47 ±35.29(P ＜0.05)respectively.In the 200 μl and 400 μl serum groups,no significant difference was detected in invasion cfu of Fn in KB cells and MMP1 secrition of KB cells among Y,N and H groups(P>0.05).Conclusion:Higher doses of smokingserum might play a role in the course of Fn invading KB cells and promote the expression of MMP1 secretion from KB cells.

Objective To observe the role of Porphyromonas P.gingivalis(P.gingivalis)invasion on monocyte adhesion to endothelium and its effect on the intercellular adhesion molecule-1(ICAM-1)produc-tion in endothelial cells.Methods A cell culture model of human umbilical vein endothelial cells (HUVEC) Was used in vitro.The adhesion of monocytes to HUVEC was detected by Rose Bengal staining with or without P.gingivalis invasion.The ICAM-1 mRNA expression in HUVEC Was determined by RT-PCR or quantikine mRNA colorimetric quantification kits.Cell surface protein of ICAM-1 in HUVEC was de-termined by Western blot with or without P.gingivalis invasion.Results The adhesion of monocyte to endo-thelium and expression of ICAM-1(both at mRNA and protein level)were found to be enhanced by P.gingi-valis invasion.Pretreatment of HUVEC with anti-ICAM-l antibody partly abolished the increase in monocyte adhesion to endothelium.Furthermore.the effect of virulent strain W83 was stronger than that of avirulent strain ATCC33277.Condusion P.gingivalis plays an important role in monocyte-endothelium adhesion partly through up regulation of ICAM-1,which may be one of the pathologic mechallisms in atherosclerosis.

Autophagy is an intracellular conservative degradation pathway. This event has been considered as a key step in host defense against bacterial infection. However, Porphyromonas gingivalis, as one of the evidence-sufficient periodontal pathogens, can utilize self-induced autophagy to achieve persistent intracellular survival and proliferation, which enable this organism to escape from host immune surveillance. This review focuses on molecular mechanism of P. gingivalis internalization and autophagy to illuminate its pathogenesis and to further explore the relationship between P. gingivalis and systemic diseases.

Objective:To study the application and effect of hybrid teaching based on the rain classroom in the teaching of periodontology for undergraduates.Methods:Sixty-four stomatological undergraduates in Phase 101 were selected as experimental group, and 62 in Phase 100 as control group. The hybrid teaching based on the rain classroom were conducted in experimental group, and mind mapping were used before and after class to help students understand and expand the content of class. The traditional teaching was adopted in the control group. SPSS 17.0 was applied to compare the differences between the written test scores and teaching satisfaction evaluation of the two groups. The learning behavior data of the students in experimental group before, during and after class were collected and analyzed.Results:The score of the written test in the experimental group were significantly better than that in the control group ( t=2.97, P<0.05). The result of questionnaire showed that the experimental group was significantly more satisfied with the improvement of lecture efficiency ( t=2.71, P<0.05) and self-learning ability ( t=4.35, P<0.05). The majority (82.55%) of students in the experimental group are in favor of the rain classroom; 89.06% of students finished the preview before class, and 67.19% of them completed the review after class. Conclusion:The hybrid teaching based on the rain classroom can be applied to the teaching of periodontology, which can effectively improve the learning quality and initiative of the students.