Dexamethasone Inhibits The TFN-α-induced Human β-defensin Expression In Gingival Epithelial Cells By Suppressing P38MAPK And NF-κB Signaling Pathway

Objectives: To investigate the effects of dexamethasone on TFN-α-induced human gingival epithelial cells hBD-1mRNA 、hBD-2 mRNA and inflammatory factors IL – 1β mRNA、IL-6 mRNA expression and the phosphorylation of nuclear factor-κB and mitogen-activated protein kinase signaling pathway.And then discussion the effects and mechanism that Dexamethasone on innate immume in oral epithelium.Method:1.Used enzymes digesting method to culture gingival epithelial of original generation cells from clinical materials.The cells were treated with25μmol/L p38 MAPK or NF-κB inhibitor for 2h,and then cultured with 10ng/ml TNF-αfor 24 h.RT-PCR was utilized to quantify the h BD-2 mRNA expression.2.Different concentrations of Dex(0.1,1,10 mu M/L)cultured the HGECs of third generation 2h respectively,and then used 10ng/ml TNF-αto induced HGECs 24 h.Adherent cells are used to extract total RNA and RT-PCR was utilized to quantify hBD-1 mRNA、hBD-2 mRNA、 IL-6 mRNA and IL-1mRNA expression with Real Time PCR.Adherent cells are used to extract totalprotein to quantify the activation of p-p65NF-κB、 p65NF-κB、 p-p38MAPK、p38MAPK and the nuclear transfer of p65NF-κB with Western Blot.All datas obtained from three independent experiments.Using SPSS17.0 software for analysis.Measurement data presented as mean ± SD,The Student’s t-test was used to analyze the statistical significance between two groups or ANOVA for multiple comparisons.The accepted level of significance was a P < 0.05.Results: 1.There was a notable decrease in hBD-2 mRNA induction by10ng/ml TNF-αby MAPK inhibitor or NF-κB inhibitor(P < 0.05)。2.The effects of Dex on TFN-α-induced hBD-1mRNA 、hBD-2 mRNA、IL – 1β mRNA、IL – 6 mRNA expression in human gingival epithelial cells.Comparion among every groups,there were showed no significant difference on TFN-α-induced hBD-1mRNA(P > 0.05);hBD-2 mRNA、 IL – 1β mRNA、IL-6 mRNA have a higher expression of HGECs induced by TFN-α compared to control group(P < 0.05);1、10μM/L Dex suppressed TFN-α-induced hBD-2mRNA expression compared with TFN-α-induced group(P < 0.05);0.1、10μM/L Dex downregulated TFN-α-induced IL – 1β mRNA expression of HGECs compared to only TFN-α-induced group;while 0.1 、 1 、 10 μ M/L Dex all suppressed TFN-α-induced IL-6 mRNA expression obviously compared to the TFN-α-induced group(P < 0.05).3.The activation of involvement NF-κB、np38MAPK signaling pathway that different concentrations of Dex downregulated TFN-α-induced hBD-2mRNA in HGECs.10ng/ml TNF-αactivated the p-p65NF-κB、 p-p38 MAPK and induced a significantly higher expression of p-p65NF-κB、p-p38 MAPK in HGECs compared to control group(P < 0.05).1、10μM/L Dex suppressed TFN-α-induced p-p65NF-κB expression in HGECs compared with only TFN-α-induced group(P < 0.05).0.1、1、10μM/L Dex all can obviouslydownregulated TFN-α-induced p-p38 MAPK expression in HGECs(P < 0.05).and with the concentrations of Dex increased p-p38 MAPK relative expression also gradually suppressed.4.TNF-αupregulated HGECs p65NF-κB expression in nucleus.0.1、1、10μ M/L Dex significantely suppressed TFN-α-induced nuclear translocation of p65 NF-κB in HGECs.Conclusions: Our results suggested that Dexamethasone inhibitss TFN-α-induced human hBD-2 mRNA 、IL-1β mRNA、IL-6 mRNA expression in human gingival epithelial cells by suppressing the NF-κB 、 p38 MAPK signaling pathways.p38 MAPK and NF-κB signaling pathway were involved in the induction of human hBD-2 in human gingival epithelial cells stimulated by TFN-α.