The roles of cyclooxygenase-2 in the pathogenesis of periodontal disease

1.探讨环氧合酶-1(COX-1)和环氧合酶-2(COX-2)在牙周病细菌刺激的人牙周成纤维细胞(HGF)分泌前列腺素E_2(PGE_2)中的作用。从牙龈卟啉单胞菌(P.gigivalis)和伴生放线杆菌(A.放线菌伴生菌)中分离得到脂多糖。内毒素制剂以剂量和时间依赖的方式产生PGE2。选择性COX抑制剂NS-398可完全抑制PGE_2的产生。COX-2免疫组织化学染色显示，牙周炎后24 h COX-2蛋白表达上调，酪氨酸激酶抑制剂可抑制COX-2蛋白表达，提示酪氨酸激酶参与了COX-2的表达。IL-4和IL-13处理IL-1α细胞可抑制PGE_2的产生，并呈剂量依赖关系。IL-4和IL-13可抑制COX-2mRNA的表达。提示IL-4和-13通过表达COX-2来调节IL-1α刺激的PDL细胞产生PGE_2。观察前列腺素E_2(PGE_2)对IL-1β刺激的肝细胞生长因子(HGF)诱导的基质金属蛋白酶-1(MMP1)表达的影响。NS-398可促进细胞产生基质金属蛋白酶-1，外源性PEG2也抑制基质金属蛋白酶-1的产生。提示前列腺素E_2通过IL-1β刺激的HGF刺激细胞产生基质金属蛋白酶-1，而IL-4和-13通过抑制前列腺素E_2的产生而促进基质金属蛋白酶-1的产生。

1. The involvement of cycloocygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in prostaglandin E_2 (PGE_2) production by human gingival fibroblasts (HGF) stimulated with periodontpathic bacteria was investigated. Lipopolysaccharides isolated from Porphyromonas gingivalis (P.gingivalis) and Actinobacillus actinomycetemcomitants (A.actinomycetemcomitans) were prepared. The LPS preparations produced PGE_2 in a dose- and time-dependent manner. P.gingivalis-LPS was a more potent stimulator than A.actinomycetemcomitans-LPS.Treatment of the cells with NS-398, a selective COX-inhibitor, completely suppresed PGE_2 production. Immunohistochemical staining of COX-2 showed that COX-2 protein expression was increased 24 h after P.gingivalis-LPS.The COX-2 expression was inhibted by treatment with tyrosine kinase inhibitors, which suggested that tyrosine kinase was involved in COX-2 expression.The effect of Th2 cytokines, interleukin (IL)-4 and -13, on PGE_2 production by IL-1alpha-stimulated periodontal ligament (PDL) cells was studied. Treatment of the IL-1alpha-cells with IL-4 and -13 inhibited PGE_2 production in a dose-dependent manner. IL-4 and -13 suppressed COX-2 mRNA expression. It was suggested that IL-4 and -13 regulate PGE_2 production by IL-1alpha-stimulatedPDL cells, through COX-2 expression.3. The effect of PGE_2 on matrix metalloproteinase-1 (MMP-1) by IL-1beta-stimulated HGF was investigated. Treatment of the cells with NS-398 enhanced MMP-1 generation and exogenous addition of PEG_2 also inhibited MMP-1 production. The data suggested that PGE_2 regulated MMP-1 production by IL-1beta-stimulated HGF.Treatment of the cells with IL-4 and -13 enhanced MMP-1 production, by inhibiting PGE_2 production.