Molecular mechanisms of cellular functional interaction in the trigeminal ganglion underlying ectopic persistent pain associated with tooth pulp inflammation

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K17077
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 57030:Conservative dentistry-related
• Research Institution: Nihon University
• Principal Investigator: OHARA KINUYO 日本大学, 歯学部, 専修医 (10731606)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 歯髄炎 / 異所性疼痛異常

Outline of Final Research Achievements

We have already reported that Hsp70 is expressed in the tooth pulp and transported to the trigeminal ganglion (TG)-cell bodies, extracellularly secreted from TG-cell bodies, and binds to TLR4 of TG neurons, which causes the enhancement of the excitability of TG neurons innervating the tongue. Based on the present study, following new findings were obtained: 1) TRPA1 expression was enhanced in the activated TG neurons via intracellular NF-kB and MAPk cascades. 2) Also, some TG cells innervating both M1 and tongue were activated by tooth pulp inflammation, causing persistent pain in the tongue.

Free Research Field

歯内療法学

Academic Significance and Societal Importance of the Research Achievements

臨床では歯髄に慢性的な炎症が引き起こされると、歯髄以外の部位(顔面皮膚、顎関節、歯根膜、舌あるいは口腔粘膜)に異所性異常疼痛として症状が生じる場合がある。つまり歯髄炎に起因する口腔顔面領域の異所性異常痛覚の症状が多岐にわたるため、疾患箇所以外に異所性異常疼痛という形で全く異なる部位に慢性の痛みを引き起こす。そのため、正確な審査・診断を困難にし、臨床上非常に大きな問題を引き起こすことがある。本研究で歯髄炎に伴う異所性異常疼痛を解明することは、原因不明の口腔顔面痛により苦しんでいる患者に適切な治療を施し、不適切な歯科治療から患者を救うことに役立つと考えられる。