Division of Oral Diagnosis, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, 1-1 Keyakidai, Sakado-City, Saitama 350-0283, Japan.
In Vivo. 2011 Jul-Aug;25(4):641-7.
The possible link between melatonin and anti-inflammatory activity is currently a focus of interest. In the present study, COX-2 expression and NF-κB activation in RAW264.7 macrophage-like cells stimulated with the fimbriae of Porphyromonas gingivalis, an oral anaerobe, in the absence and presence of melatonin were investigated.
The cytotoxicity of melatonin and indole against RAW264.7 cells was determined using a cell counting kit. The regulatory effect of melatonin, and of indole on the expression of COX-2 mRNA stimulated by exposure to the fimbriae was investigated by Northern blot analysis. NF-κB activation was evaluated by both electrophoretic mobility-shift assay and Western blot analysis.
The half maximal (50%) effective concentration (EC(50)) values for melatonin and indole were 3300 μM and 130 μM, respectively. Melatonin at non-cytotoxic concentrations significantly inhibited the fimbria-induced expression of COX-2. The fimbria-stimulated binding of NF-κB to its consensus sequence and phosphorylation-dependent proteolysis of inhibitor κB-α were markedly inhibited by melatonin. However, indole did not inhibit COX-2 expression and NF-κB activation.
Melatonin may be able to prevent diseases induced by oral bacteria.
褪黑素与抗炎活性之间的可能联系是目前研究的热点。本研究探讨了褪黑素和色氨酸在牙龈卟啉单胞菌菌毛刺激 RAW264.7 巨噬样细胞后，对环氧化酶-2（COX-2）表达和核因子-κB（NF-κB）激活的影响。
用细胞计数试剂盒检测褪黑素和色氨酸对 RAW264.7 细胞的细胞毒性。采用Northern blot 分析检测褪黑素和色氨酸对菌毛刺激诱导的 COX-2 mRNA 表达的调控作用。通过电泳迁移率变动分析和 Western blot 分析评估 NF-κB 的激活。
褪黑素和色氨酸的半最大有效浓度（EC50）值分别为 3300 μM 和 130 μM。非细胞毒性浓度的褪黑素显著抑制菌毛诱导的 COX-2 表达。褪黑素明显抑制 NF-κB 与其共有序列的结合以及依赖磷酸化的抑制蛋白 κB-α的蛋白水解。然而，色氨酸不能抑制 COX-2 表达和 NF-κB 激活。
褪黑素可能具有预防口腔细菌引起的疾病的作用。
