Analysis of relationship between periodontal tissue para-inflammation induced neuroinflammation and phagocytic activity regulation by circadian cloclk system

为了阐明慢性炎症性牙周病(又称副炎性牙周病)引起的认知损害的机制，我们建立了牙周病的动物模型。牙周炎杆菌(PG)作用于牙周组织后，牙周组织和大脑皮层均有致炎细胞因子的表达。小胶质细胞在神经炎性条件下通过产生促炎细胞因子参与认知损害。最近的研究表明，小胶质细胞的能力具有昼夜节律。应用PG后，大鼠脑小胶质细胞和牙周组织巨噬细胞中促炎症细胞因子mRNA表达水平呈昼夜节律性变化。这些结果提示，牙周组织和脑吞噬细胞促炎细胞因子基因表达的昼夜节律可能影响牙周组织炎症和认知功能障碍的进展。

To elucidate the mechanism of cognitive impairment by chronic inflammatory periodontal disease, also known as para-inflammation disease, we developed animal models of periodontal disease. After the application of P. gingivalis (PG) to periodontal tissues, proinflammatory cytokines were expressed at the periodontal tissue and cerebral cortex. and intraperitoneal administration of PG caused cognitive impairment.Microglia involved in cognitive impairment by producing proinflammatory cytokines under neuroinflammatory conditions. And recent studies showed that the abilities of microglia showed circadian rhythm. After the application of PG, proinflammatory cytokine mRNA expression levels in brain microglia and periodontal tissue macrophages showed circadian rhythm. These results suggested that circadian rhythm of proinflammatory cytokine gene expressions by periodontal tissue and brain phagocytes may affect periodontal tissue inflammation and cognitive impairment progression.