2018 Fiscal Year Final Research Report

Elucidation of the disease mechanism of chronic pain associated with masticatory muscle pain disorder using masticatory muscle pain disorder model animal

Research Project

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Project/Area Number	16K11533
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Pathobiological dentistry/Dental radiology
Research Institution	Osaka Dental University
Principal Investigator	KUMABE Shunji 大阪歯科大学, 歯学部, 教授 (30288774)
Co-Investigator(Kenkyū-buntansha)	乾千珠子 (山本千珠子) 大阪大学, 歯学研究科, 助教 (00419459) 中塚美智子大阪歯科大学, 医療保健学部, 准教授 (70368158) 神光一郎大阪歯科大学, 医療保健学部, 准教授 (00454562)
Project Period (FY)	2016-04-01 – 2019-03-31
Keywords	咀嚼筋痛障害 / 筋筋膜痛症候群
Outline of Final Research Achievements	In this basic research study focused on developing a treatment for masticatory muscle pain disorder, we experimentally induced inflammation in the masseter muscles. In addition, we aimed to try that we developed the model rats of myofascial pain syndrome. Glia have been linked to inflammatory hyperalgesia, and it has been suggested that the activation of glia in the spinal cord is involved in mechanisms underlying inflammatory pain, neurogenic pain, hyperalgesia, and allodynia. We investigated the role of astrocytes in the Vc by examining histological changes in the masseter muscle and Vc over time. When inflammation in the masticatory muscle was induced by the administration of LPS, which is an inflammatory factor, and a 6% sodium chloride solution, which is an infringing factor, activated microglias and astrocytes in the Vc, even after local inflammation had subsided, which suggested a transition to chronic pain.
Free Research Field	口腔解剖学
Academic Significance and Societal Importance of the Research Achievements	口腔顎顔面領域の神経損傷由来の慢性痛に関しては、先行研究で数多くのことが解明されてきた。しかし咀嚼筋痛障害の病態について未だ解明されていない点が多く、治療法も確立されていなかった。本研究により、咀嚼筋に炎症を起こした場合、局所の炎症は消退してもなお脳幹においてグリア細胞および細胞内情報伝達系の活性化が持続し、痛みの慢性化に移行する可能性があることが示唆された。このことより、咀嚼筋痛障害や筋筋膜痛症候群の治療のターゲットの１つとしてグリア細胞を検討する必要があることを示した。