Mutoh Noriko, Tani-Ishii Nobuyuki, Tsukinoki Keiichi, Chieda Keiko, Watanabe Kiyoko
Department of Maxillofacial Diagnostic Science, Division of Pathology, Kanagawa Dental College, Kanagawa, Japan.
J Endod. 2007 Oct;33(10):1183-6. doi: 10.1016/j.joen.2007.05.018. Epub 2007 Jul 26.
Toll-like receptors (TLRs) are important factors in innate immune responses because they mediate signals from bacterial cell wall components during inflammatory reactions. However, the role of TLR in dental pulp, which is bounded by hard tissues, is little understood. The present study investigated the expression of TLR-2 and TLR-4 in experimentally inflamed pulp by quantitative real-time polymerase chain reaction and immunohistochemistry. Total RNA isolated from pulp tissue from 0 to 72 hours after bacterial dentinal infection. The TLR-2 messenger RNA (mRNA) level was 30-fold higher than the TLR-4 mRNA level at 9 hours. The TLR-2 mRNA level in pulp began to increase by 3 hours after bacterial infection, reaching a maximum level after 9 hours and gradually decreasing from 9 to 72 hours. Numerous TLR-2- and CD64-positive cells detected on macrophage and dendritic-like cells, TLR-4-positive cells detected a little in the pulp at 9 hours. These results suggest that TLR-2 may be mainly regulated during the early stage of pulp inflammation triggered by bacterial infection.
Toll样受体（TLRs）是天然免疫反应中的重要因素，因为它们在炎症反应过程中介导来自细菌细胞壁成分的信号。然而，TLR在被硬组织包围的牙髓中的作用却鲜为人知。本研究通过定量实时聚合酶链反应和免疫组织化学方法，研究了实验性炎症牙髓中TLR-2和TLR-4的表达。从细菌感染牙本质后0至72小时的牙髓组织中分离总RNA。在9小时时，TLR-2信使核糖核酸（mRNA）水平比TLR-4 mRNA水平高30倍。牙髓中的TLR-2 mRNA水平在细菌感染后3小时开始升高，在9小时后达到最高水平，并在9至72小时逐渐下降。在巨噬细胞和树突状样细胞上检测到大量TLR-2和CD64阳性细胞，在9小时时牙髓中检测到少量TLR-4阳性细胞。这些结果表明，TLR-2可能在细菌感染引发的牙髓炎症早期主要发挥调节作用。
