Noguchi K, Yanai M, Shitashige M, Nishihara T, Ishikawa I
Department of Periodontology, Faculty of Dentistry, Tokyo Medical and Dental University, Japan.
J Periodontol. 2000 Oct;71(10):1575-82. doi: 10.1902/jop.2000.71.10.1575.
Prostaglandin E2 (PGE2) plays important roles in the pathogenesis of periodontal disease. Recent studies have revealed the existence of 2 isozymes of cyclooxygenase (COX), called COX-1 and COX-2. The purpose of the present study was to investigate the contribution of COX-1 and COX-2 to PGE2 production by human peripheral blood monocytes that are stimulated with lipopolysaccharides (LPS) from periodontopathogenic bacteria.
LPS were isolated from Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) and Porphyromonas gingivalis (P. gingivalis) by the phenol-water method. Peripheral blood monocytes were stimulated with LPS for the indicated periods, and the levels of PGE2 or interleukin (IL)-1 beta in the culture media were measured by enzyme-linked immunosorbent assay. Expression of COX-1 and -2 proteins was studied by immunocytochemical staining, and COX-2 mRNA expression was examined by Northern blot analysis.
Peripheral blood monocytes stimulated with A. actinomycetemcomitans- or P. gingivalis-LPS produced PGE2 in a time- and dose-dependent manner. Indomethacin, a non-selective COX-1/COX-2 inhibitor, and NS-398, a specific COX-2 inhibitor, completely inhibited PGE2 production. Immunocytochemical staining of COX-1 and COX-2 proteins showed that expression of COX-2 protein was increased in monocytes that were stimulated with A. actinomycetemcomitans- or P. gingivalis-LPS, compared with that in unstimulated monocytes, whereas expression of COX-1 protein was not altered. Northern blot analysis showed that monocytes stimulated with A. actinomycetemcomitans- or P. gingivalis-LPS expressed COX-2 mRNA, while COX-2 mRNA was not detectable in unstimulated cells. Treatment of A. actinomycetemcomitans-LPS-stimulated monocytes with NS-398 induced a significant increase of IL-1 beta production to the same extent as treatment with indomethacin.
These results suggest that COX-2 is induced in monocytes stimulated with LPS derived from A. actinomycetemcomitans and P. gingivalis and that the COX-2 is primarily responsible for PGE2 production. COX-2 may be pivotal in PGE2 production in periodontal lesions and may be involved in inflammatory responses.
前列腺素E2（PGE2）在牙周病的发病机制中起重要作用。最近的研究揭示了环氧化酶（COX）的两种同工酶的存在，即COX - 1和COX - 2。本研究的目的是调查COX - 1和COX - 2对由牙周病原菌的脂多糖（LPS）刺激的人外周血单核细胞产生PGE2的作用。
通过酚 - 水法从伴放线放线杆菌（A. actinomycetemcomitans）和牙龈卟啉单胞菌（P. gingivalis）中分离LPS。用LPS刺激外周血单核细胞指定的时间，通过酶联免疫吸附测定法测量培养基中PGE2或白细胞介素（IL）-1β的水平。通过免疫细胞化学染色研究COX - 1和 - 2蛋白的表达，并通过Northern印迹分析检测COX - 2 mRNA的表达。
用A. actinomycetemcomitans - 或P. gingivalis - LPS刺激的外周血单核细胞以时间和剂量依赖性方式产生PGE2。非选择性COX - 1/COX - 2抑制剂吲哚美辛和特异性COX - 2抑制剂NS - 398完全抑制PGE2的产生。COX - 1和COX - 2蛋白的免疫细胞化学染色显示，与未刺激的单核细胞相比，用A. actinomycetemcomitans - 或P. gingivalis - LPS刺激的单核细胞中COX - 2蛋白的表达增加，而COX - 1蛋白的表达未改变。Northern印迹分析显示，用A. actinomycetemcomitans - 或P. gingivalis - LPS刺激的单核细胞表达COX - 2 mRNA，而在未刺激的细胞中未检测到COX - 2 mRNA。用NS - 398处理A. actinomycetemcomitans - LPS刺激的单核细胞可诱导IL - 1β产生显著增加，其程度与用吲哚美辛处理相同。
这些结果表明，在用源自A. actinomycetemcomitans和P. gingivalis的LPS刺激的单核细胞中诱导了COX - 2，并且COX - 2主要负责PGE2的产生。COX - 2可能在牙周病变中PGE2的产生中起关键作用，并可能参与炎症反应。
