[Effects of Porphyromonas endodontalis lipopolysaccharides on the expression of monocyte chemotactic protein-1 in mouse osteoblasts].

PURPOSE: To investigate the effects of lipopolysaccharide (LPS) extracted from Porphyromonas endodontalis (P.endodontalis) on expression of monocyte chemotactic protein-1 (MCP-1) mRNA and protein in MC3T3-E1 cells and the role of p38 mitogen-activated　protein　kinase (MAPK) and nuclear factor-kB(NF-kB）in the process. METHODS: MC3T3-E1 cells were treated with different concentrations of P.endodontalis LPS(0-50mg/L) and 20 mg/L P.endodontalis LPS for different hours (0-48 h). The expression of MCP-1 mRNA was detected by real-time reverse transcription PCR(RT-PCR) and protein was detected by enzyme-1inked immunosorbent assay (ELISA). MC3T3-E1 cells were pretreated with SB203580 (inhibitor of p38MAPK) and BAY11-7082 (inhibitor of NF-kB) for 1h, and then were treated with 20 mg/L P.endodontalis LPS for 24 h, the expression of MCP-1 mRNA was also detected by RT-PCR. Statistical analysis was performed using one-way ANOVA and Dunnett t test with SPSS 13.0 software package. RESULTS: The level of MCP-1 mRNA and protein increased significantly after treatment with different concentrations of P.endodontalis LPS (0-50 mg/L), which indicated that P.endodontalis LPS induced osteoblasts to express MCP-1 in a dose dependent manners. During the observation time (0-48 h), the impact of 20 mg/L P.endodontalis LPS on induction of MCP-1 in MC3T3-E1 cells exhibited a time-dependent manner. The expression of MCP-1 mRNA decreased significantly after pretreated with 10 mol/L SB203580 and BAY11-7082 for 1 h,and the inhibitory effect of SB203580 was stronger than BAY11-7082. CONCLUSIONS: P.endodontalis LPS may induce the expression of MCP-1 mRNA and protein in MC3T3-E1 cells through the signaling pathway of p38MAPK and NF-kB.

[Expression of SOCS-1 and SOCS-3 in chronic periapical lesions and its clinical significance].

PURPOSE: To detect the expression of suppressor of cytokine signaling-1 (SOCS-1) and suppressor of cytokine signaling-3 (SOCS-3) in chronic periapical lesions and to clarify their roles in pathogenesis of apical periodontitis. METHODS: A total of 25 chronic periapical lesion tissues and 16 normal periodontal ligament tissues were collected respectively. The expression of mRNA was measured by real-time PCR, the protein expression was measured by immunohistochemical analysis. Statistical analysis was performed using SPSS 13.0 software package. RESULTS: Immunohistochemical results indicated that expression levels of SOCS-1 and SOCS-3 protein in chronic periapical lesions were significantly higher than that in normal tissues (P<0.01); Moreover, SOCS-1 and SOCS-3 protein expression levels in severe inflammation group were significantly higher than that in mild inflammation group (P<0.01). In mild inflammation group, severe inflammation group and control group, the expression levels of SOCS-1 mRNA were 2.620±1.552, 2.373±1.083 and 1.277±1.040, whereas those of SOCS-3 were 9.308±5.901, 7.565±3.233 and 1.232±1.099, respectively. CONCLUSIONS: The expression levels of SOCS-1 mRNA and SOCS-3 mRNA are significantly higher both in mild inflammation group and severe inflammation group than that in control group (P<0.01), while no significant difference is found in mild and severe inflammation group.