Nisapakultorn Kanokwan, Makrudthong Jittima, Sa-Ard-Iam Noppadol, Rerkyen Pimprapa, Mahanonda Rangsini, Takikawa Osamu
Department of Periodontology, Chulalongkorn University, Bangkok, Thailand.
J Periodontol. 2009 Jan;80(1):114-21. doi: 10.1902/jop.2009.080315.
Indoleamine 2,3-dioxygenase (IDO) is an intracellular tryptophan-oxidizing enzyme with immunosuppressive characteristics. Its expression and regulation in periodontal tissues are unknown. The aim of this study was to determine IDO expression in healthy gingiva and chronic periodontitis lesions. In addition, the effect of inflammatory cytokines and bacterial products on the expression and activity of DOI in human gingival fibroblasts (HGFs) was assessed.
Human gingival tissue samples were obtained from patients who underwent periodontal surgery. IDO expression in healthy gingiva and periodontitis lesions was determined by immunohistochemistry. HGF cells were treated with interferon-gamma (IFN-gamma), interleukin (IL)-1beta, tumor necrosis factor-alpha (TNF-alpha), and lipopolysaccharides from Porphyromonas gingivalis (PgLPS). IDO mRNA expression was determined by reverse transcription-polymerase chain reaction. The IDO enzymatic activity was determined by measuring the kynurenine level using a colorimetric method.
In gingival tissues, IDO expression was detected in epithelial cells, fibroblasts, endothelial cells, and inflammatory mononuclear cells. IDO expression was higher in periodontitis lesions than in healthy gingiva. HGFs did not constitutively express IDO. IFN-gamma strongly induced IDO expression and activity in HGFs, in a dose-dependent manner. IL-1beta, TNF-alpha, and PgLPS were also able to induce IDO expression in HGF cells. IFN-gamma in combination with IL-1beta, TNF-alpha, or PgLPS showed enhanced IDO expression.
IDO was expressed in human gingiva, and the expression was upregulated in chronic periodontitis. The increased IDO expression in periodontitis lesions may be due, in part, to the activation of HGFs by inflammatory cytokines and bacterial products.
吲哚胺2,3-双加氧酶（IDO）是一种具有免疫抑制特性的细胞内色氨酸氧化酶。其在牙周组织中的表达及调控情况尚不清楚。本研究旨在确定IDO在健康牙龈和慢性牙周炎病变中的表达。此外，评估了炎性细胞因子和细菌产物对人牙龈成纤维细胞（HGFs）中IDO表达及活性的影响。
从接受牙周手术的患者获取人牙龈组织样本。通过免疫组织化学法确定健康牙龈和牙周炎病变中IDO的表达。用干扰素-γ（IFN-γ）、白细胞介素（IL）-1β、肿瘤坏死因子-α（TNF-α）以及牙龈卟啉单胞菌脂多糖（PgLPS）处理HGF细胞。通过逆转录-聚合酶链反应确定IDO mRNA表达。采用比色法通过测量犬尿氨酸水平来确定IDO酶活性。
在牙龈组织中，上皮细胞、成纤维细胞、内皮细胞和炎性单核细胞中均检测到IDO表达。牙周炎病变中的IDO表达高于健康牙龈。HGFs不组成性表达IDO。IFN-γ以剂量依赖性方式强烈诱导HGFs中IDO的表达及活性。IL-1β、TNF-α和PgLPS也能够诱导HGF细胞中IDO的表达。IFN-γ与IL-1β、TNF-α或PgLPS联合使用时，IDO表达增强。
IDO在人牙龈中表达，且在慢性牙周炎中表达上调。牙周炎病变中IDO表达增加可能部分归因于炎性细胞因子和细菌产物对HGFs的激活。
