ラット象牙芽細胞様細胞 (KN-3) におけるカテキンの抗炎症作用  [in Japanese] Anti-inflammatory Effects of Catechin on Rat Odontoblastic Cells (KN-3)  [in Japanese]

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Author(s)

    • 平尾 功治 Kouji HIRAO
    • 徳島大学大学院医歯薬学研究部 歯科保存学分野 Department of Conservative Dentistry, Tokushima University Graduate School of Biomedical Sciences
    • 湯本 浩通 Hiromichi YUMOTO
    • 徳島大学大学院医歯薬学研究部 歯科保存学分野 Department of Conservative Dentistry, Tokushima University Graduate School of Biomedical Sciences
    • 細川 由樹 Yuki HOSOKAWA
    • 徳島大学大学院医歯薬学研究部 歯科保存学分野 Department of Conservative Dentistry, Tokushima University Graduate School of Biomedical Sciences
    • 蔵本 瞳 Hitomi KURAMOTO
    • 徳島大学大学院医歯薬学研究部 歯科保存学分野 Department of Conservative Dentistry, Tokushima University Graduate School of Biomedical Sciences
    • 鷲尾 絢子 Ayako WASHIO
    • 九州歯科大学口腔機能学講座口腔保存治療学分野 Division of Endodontics and Restorative Dentistry, Department of Science of Oral Functions, Kyushu Dental University
    • 中西 正 Tadashi NAKANISHI
    • 徳島大学大学院医歯薬学研究部 歯科保存学分野 Department of Conservative Dentistry, Tokushima University Graduate School of Biomedical Sciences
    • 武川 大輔 Daisuke TAKEGAWA
    • 徳島大学大学院医歯薬学研究部 歯科保存学分野 Department of Conservative Dentistry, Tokushima University Graduate School of Biomedical Sciences
    • 北村 知昭 Chiaki KITAMURA
    • 九州歯科大学口腔機能学講座口腔保存治療学分野 Division of Endodontics and Restorative Dentistry, Department of Science of Oral Functions, Kyushu Dental University
    • 松尾 敬志 Takashi MATSUO
    • 徳島大学大学院医歯薬学研究部 歯科保存学分野 Department of Conservative Dentistry, Tokushima University Graduate School of Biomedical Sciences

Abstract

<p> 目的 : 象牙芽細胞は歯髄の最外層に存在し, 齲蝕関連病原因子や機械的刺激・化学的刺激に対して, 初期に反応し, 歯髄組織の自然免疫に重要な役割を担っている. われわれは, ラット象牙芽細胞様細胞 (KN-3) に自然免疫レセプターであるnucleotide-binding oligomerization domein (NOD) 1が発現, 機能していることを報告しており, NOD1は歯髄炎の発症, 進展に重要な役割を演じている可能性がある. 緑茶カテキンの一種であるepigallocatechin-3-gallate (EGCG) は抗炎症作用を有することが知られており, NOD1リガンドならびに炎症性サイトカインの刺激を受けた象牙芽細胞に対するEGCGの抗炎症作用について解析することを目的とし研究を行った. </p><p> 材料と方法 : EGCGのKN-3に対する細胞障害性を, lactate dehydrogenase (LDH) cytotoxicity assayを用いて調べた. NOD1特異的リガンドであるγ-D-diaminopimelic acid (iE-DAP) やtumor necrosis factor (TNF) -α, interleukin (IL) -1βにてKN-3を刺激し, 同時にEGCGを作用させた後, real-time polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA) を用い, ケモカインや炎症性メディエーターの発現や産生について解析を行った. </p><p> 成績 : 10μg/m<i>l</i>までのEGCGはKN-3への細胞障害性を認めなかった. iE-DAPや炎症性サイトカインで刺激したKN-3に対して, EGCGはcytokine-induced neutrophil chemoattractant (CINC) -2やC-C motif chemokine ligand (CCL) 20といったケモカインの産生を有意に抑制し, その作用は濃度依存的であった. さらに, EGCGはinducible nitric oxide synthase (iNOS) のmRNA発現も抑制した. </p><p> 結論 : 今回の研究において, EGCGがNOD1リガンドならびにサイトカイン刺激におけるラット象牙芽細胞様細胞 (KN-3) の種々の炎症性反応を抑制することが明らかとなった. この結果は, EGCGの応用が, 新たな歯髄炎の抗炎症療法となりうる可能性を示唆するものである. </p>

<p> Purpose: Odontoblasts, which are located in the outermost layer of dental pulp, first recognize caries-related pathogens, sense such external mechanical and chemical irritations, and play important roles in the innate immune system of dental pulp tissues. We recently reported that nucleotide-binding oligomerization domain (NOD) 1, one of the pattern recognition receptors in innate immunity, is expressed in rat odontoblastic cells (KN-3) and functions to up-regulate the chemokines expression, and suggested that NOD1 may play important roles in the initiation and progression of pulpitis. It has been reported that epigallocatechin gallate (EGCG), one of the major active components of green tea catechin, has anti-inflammatory effects. The aim of this study was to determine the anti-inflammatory effects of EGCG on odontoblasts stimulated with NOD1-specific ligand or pro-inflammatory cytokines.</p><p> Methods: The cytotoxicity of EGCG to KN-3, rat odontoblastic cell line, was analyzed by lactate dehydrogenase (LDH) cytotoxicity assay. γ-D-diaminopimelic acid (iE-DAP), NOD1-specific ligand, tumor necrosis factor (TNF) -α- or interleukin (IL) -1β-stimulated KN-3 was treated with EGCG and then the expression and production of pro-inflammatory mediators, such as chemokines and inducible nitric oxide synthase (iNOS), were determined by real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), respectively.</p><p> Results: EGCG (up to 10μg/m<i>l</i>) had no cytotoxic effect on KN-3. EGCG significantly inhibited the production of chemokines, such as cytokine-induced neutrophil chemoattractant (CINC) -2 and C-C motif chemokine ligand (CCL) 20, in a dose-dependent manner. The expression of iNOS mRNA was also significantly reduced by treatment with EGCG at 10μg/m<i>l</i>.</p><p> Conclusions: These findings demonstrated that EGCG treatment significantly reduced the expression and production of various pro-inflammatory mediators via NOD1-mediated innate immune response as well as inflammatory response elicited by TNF-α or IL-1β stimulation in rat odontoblastic cells (KN-3), suggesting that EGCG might be useful therapeutically as an anti-inflammatory modulator of dental pulpal inflammation.</p>

Journal

  • The Japanese Journal of Conservative Dentistry

    The Japanese Journal of Conservative Dentistry 60(5), 235-244, 2017

    The Japanese Society of Conservative Dentistry

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