Department of Periodontology, Stomatological Hospital, Southern Medical University, Guangzhou, China.
Department of Oral Medicine, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.
J Periodontal Res. 2021 Aug;56(4):782-788. doi: 10.1111/jre.12877. Epub 2021 Mar 17.
The aim of this study was to determine the potential role of TLR-4 in the osteoimmunological imbalance of periodontitis.
Although current evidence supports that TLR-4 plays an important role in the inflammatory response of periodontal tissues triggered by microorganisms, little information is available regarding the function of TLR-4 in the osteoimmune regulation of homeostasis in periodontitis.
Human gingival epithelial cells (HGEC) were isolated from the gingival tissues of 3 healthy volunteers and the expression of osteoclastogenic cytokines was evaluated by ELISA and real time RT-PCR. In addition, 30 C57BL/6 mice were used and randomly divided into three groups: control group, periodontitis group (CP) and periodontitis+TAK-242 (a specific inhibitor of TLR-4) group (TAK-242) and the expression of osteoclastogenic cytokines and the osteoclast density in the periodontal tissue were evaluated by immunohistochemical staining and tartrate resistant acid phosphatase staining. Moreover, micro-computed tomography (Micro-CT) was used to assess bone resorption.
The in vitro results showed that TAK-242 blocked the overproduction of IL-1, IL-6, TNF-α and RANKL in HGEC treated with LPS. The in vivo results revealed that TAK-242 also effectively decreased these osteoclastogenic cytokines in periodontal tissue of mice with periodontitis. More importantly, Micro-CT analysis showed a significant reduction of the alveolar bone loss in the TAK-242 group compared with the CP group. Furthermore, the TRAP staining showed a significant lower density of osteoclasts in the alveolar bone area of the TAK-242 group.
TLR-4 inhibition decreased the differentiation of osteoclast through the inhibition of the overproduction of osteoclastogenic cytokines and the prevention of the alveolar bone absorption in mouse periodontitis models. Therefore, the use of TAK-242 might contribute to the recovery of the osteoimmunological homeostasis and might provide a potential strategy to treat periodontal diseases.
本研究旨在确定 TLR-4 在牙周炎骨免疫学失衡中的潜在作用。
尽管目前的证据支持 TLR-4 在微生物触发的牙周组织炎症反应中发挥重要作用，但关于 TLR-4 在牙周炎骨免疫稳态调节中的功能知之甚少。
从 3 名健康志愿者的牙龈组织中分离出人牙龈上皮细胞（HGEC），通过 ELISA 和实时 RT-PCR 评估破骨细胞生成细胞因子的表达。此外，使用 30 只 C57BL/6 小鼠并将其随机分为三组：对照组、牙周炎组（CP）和牙周炎+TAK-242（TLR-4 的特异性抑制剂）组（TAK-242），通过免疫组织化学染色和抗酒石酸酸性磷酸酶染色评估牙周组织中破骨细胞生成细胞因子的表达和破骨细胞密度。此外，使用微计算机断层扫描（Micro-CT）评估骨吸收。
体外结果显示，TAK-242 阻断了 LPS 处理的 HGEC 中过度产生的 IL-1、IL-6、TNF-α 和 RANKL。体内结果表明，TAK-242 还能有效减少牙周炎小鼠牙周组织中这些破骨细胞生成细胞因子。更重要的是，Micro-CT 分析显示 TAK-242 组与 CP 组相比，牙槽骨丢失明显减少。此外，TRAP 染色显示 TAK-242 组牙槽骨区域破骨细胞密度明显降低。
TLR-4 抑制通过抑制破骨细胞生成细胞因子的过度产生和防止小鼠牙周炎模型中牙槽骨吸收，减少破骨细胞的分化。因此，使用 TAK-242 可能有助于恢复骨免疫学稳态，并为治疗牙周病提供一种潜在策略。
