[17-ß estradiol promotes the expression of interleukin-6 in human periodontal ligament cells infected with Porphyromonas gingivalis].

OBJECTIVE: To investigate the effects of 17-ß estradiol (E(2)) and Porphyromonas gingivalis (Pg) W83 on the expression of interleukin (IL)-6 and IL-8 in human periodontal ligament cells (hPDLC). METHODS: Primary cultures of hPDLC were established and the cells of passage four were treated with 10(-10) mol/L E(2), 10(-7) mol/L E(2) or PgW83 individually or E(2) combined with PgW83. The expression levels of IL-6 and IL-8 protein at 12 h and 24 h were measured with enzyme-linked immunosorbent assay and the levels of mRNA at 24 h were detected with real-time reverse transcriptase polymerase chain reaction. RESULTS: The expression level of IL-6 reached (2482.88 ± 26.53) ng/L in hPDLC treated with Pg at multiplicity of infection (MOI) of 100 for 24 h, which was significantly higher than that in hPDLC treated with Pg at MOI of 10:1 [(734.09 ± 87.90) ng/L, P = 0.000], the controls [(425.8 ± 77.25) ng/L, P = 0.000] and that in hPDLC treated with Pg at MOI of 100 for 12 h [(1157.50 ± 234.65) ng/L, P = 0.000]. The expression level of IL-8 reached (4965.81 ± 1072.55) ng/L in hPDLC treated with Pg at MOI of 100 for 24 h, which was significantly higher than that in hPDLC treated with Pg at MOI of 10 [(803.51 ± 162.08) ng/L, P = 0.007], the controls [(400.75 ± 2.27) ng/L, P = 0.005] and that in hPDLC treated with Pg at MOI of 100 for 12 h [(1431.12 ± 82.78) ng/L, P = 0.001]. E(2) did not show remarkable effect on the expressions of IL-6 and IL-8. E(2) combined with Pg (MOI = 100:1) significantly promoted the expression levels of IL-6 at 24 h while did not influence those of IL-8. The relative mRNA level of IL-6 in hPDLC treated with 10(-10) mol/L E(2) or 10(-7) mol/L E(2) combined with Pg were 0.49 ± 0.15 (P = 0.021)and 0.53 ± 0.16 (P = 0.036) individually, which were significantly higher than that treated with Pg alone, 0.19 ± 0.06. The protein level of IL-6 in hPDLC treated with 10(-10) mol/L E(2) or 10(-7) mol/L E(2) combined with Pg were (5512.66 ± 1022.07) ng/L (P = 0.012) and (6988.78 ± 2279.13) ng/L (P = 0.000) individually, which were significantly higher than that treated with Pg alone, (3138.46 ± 183.72) ng/L. CONCLUSIONS: PgW83 significantly increased the expression levels of IL-6 and IL-8 in hPDLC in a dose-and time-dependent manner. Without the infection of periodontal pathogens, estrogen may exert no effect on the expression of IL-6 and IL-8 while it may promote the expression of IL-6 in hPDLC when combined with Pg, which may in turn promote the process of periodontal inflammation.

[Effect of lipopolysaccharides extracted from Porphyromonas endodontalis on the expression of p38 and ERK1/2 in osteoblast].

PURPOSE: To investigate the effect of lipopolysaccharides (LPS) extracted from Porphyromonas endodontalis(P.e) on the expression of p38 and ERK1/2 in osteoblast. METHODS: MC3T3-E1 cells were stimulated with 10 µg/mL P.e-LPS for 0,5,15,30,60,180 min. The phosphorylation of p38 and ERK1/2 was measured by Western blot. Statistical analysis was performed using one- way ANOVA and Dunnett t test with SPSS11.0 software package. RESULTS: 10 µg/mL LPS could significantly activate p38 MAPK. The peak of phosphorylated p38 was detected at 5 to 30 min(P<0.01) and returned to baseline within 60 min; the level of phosphorylated ERK1/2 increased after the stimulation of LPS for 5 min and reached maximum at 15 min (P<0.01) and declined after 30 min. CONCLUSIONS: P.e-LPS can induce the expression of p38 and ERK1/2 in osteoblast MC3T3-E1, which indicates that P.e-LPS may play an important role in osteoblast through p38 and ERK1/2.

[Research on the effect of root canal seal achieved by irradiation of Er, Cr:YSGG laser].

PURPOSE: To evaluate the effect of root canal seal achieved by routine root canal preparation and irradiation of Er, Cr:YSGG laser in root canal therapy. METHODS: One hundred and five freshly single-rooted extracted human teeth were selected for the study, which were randomly divided into seven groups of fifteen each. The anatomic crowns were removed at the cementoenamel junction and the remaining roots were prepared endodontically with conventional methods. Then they were treated with Er, Cr:YSGG laser in different parameters and patterns. The effect of root canal seal achieved by Er, Cr:YSGG laser was evaluated with microleakage measurements. Newman-Keuls test and one-way analysis of variance were used to determine the statistical differences between various groups. A value of P<0.05 was considered to be significant. RESULTS: The amount of dye penetration from an apical stop with irradiation of Er, Cr:YSGG laser was significantly lower (P<0.05) except 3W laser without water flow, and in 1W Er, Cr:YSGG laser without water flow, the amount of apical dye penetration was significantly decreased (P<0.01). CONCLUSIONS: The utilizing of Er, Cr:YSGG laser in small parameters prior to root canal filling could promote the effect of apical seal. Based on our results, it appeared that the seal effect of 1W Er, Cr:YSGG laser without water flow was superior to the effects of others.