Experimental study on involvement of the central nervous system in inferior alveolar nerve damage-associated hyperalgesia of the mental region

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K11269
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Surgical dentistry
• Research Institution: Showa University
• Principal Investigator: Shirota Tatsuo 昭和大学, 歯学部, 教授 (60235760)
• Co-Investigator(Kenkyū-buntansha): 韓 仁陽 (清本聖文) 昭和大学, 歯学部, 兼任講師 (00712556) ; 近藤 誠二 昭和大学, 歯学部, 兼任講師 (10432634)
• Research Collaborator: Nakamura Masanori ; Inoue Tomio
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 下歯槽神経損傷 / マイクログリア / アストログリア / 三叉神経脊髄路核尾側亜核 / 機械的痛覚過敏 / 神経因性疼痛

Outline of Final Research Achievements

The rat inferior alveolar nerve was damaged by ligation with thread, and the course of behavioral changes after surgery was observed for 42 days. In addition, activation of microglia and astroglia in the trigeminal spinal subnucleus caudalis (Vc) was analyzed using immunohistochemistry, and anti-c-fos antibody-reactive cells were quantitatively evaluated to analyze the state of neuron excitement. Withdrawal threshold was significantly decreased 5 days after surgery in the inferior alveolar nerve ligated (IANL) group compared with that in the sham group, and subsequently recovered over time. In addition, microglia and astroglia were activated in the Vc region 5 days after surgery in the model group, and anti-c-fos antibody-reactive cells were also significantly more frequent in the IANL group.

Free Research Field

口腔外科学

Academic Significance and Societal Importance of the Research Achievements

下顎枝矢状分割術は基本術式通りに施行しても，比較的高い頻度でオトガイ神経知覚異常が発症することが知られている。術後このような神経症状が残存した場合には，ステロイド剤の投与，ビタミンB複合体の投与あるいはATTP製剤の投与などが行われているが，その効果は明らかではなく，効果的な治療法は未だ確立されていない。
下歯槽神経損傷に伴うオトガイ部の痛覚過敏の慢性化には中枢神経系におけるマイクログリア-アストログリア－ニューロン間の相互作用の関与を示唆した本研究の成果は術後のオトガイ神経知覚異常の診断，治療そして予防に貢献するものと考えられる。