2019 Fiscal Year Final Research Report

Nasal obstruction induces Class II malocclusion with changing GLUT4 and HIF-1a expression

Research Project

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Project/Area Number	16K11782
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Orthodontics/Pediatric dentistry
Research Institution	Tokyo Medical and Dental University
Principal Investigator	Yonemitsu Ikuo 東京医科歯科大学, 大学院医歯学総合研究科, 助教 (00431940)
Co-Investigator(Kenkyū-buntansha)	細道純東京医科歯科大学, 大学院医歯学総合研究科, 講師 (00420258)
Project Period (FY)	2016-04-01 – 2020-03-31
Keywords	鼻呼吸障害 / 顎関節 / 咀嚼筋 / 顎顔面成長発育 / GLUT4 / HIF-1α
Outline of Final Research Achievements	In the unilateral nasal obstruction(NO) group,length,bone mineral density and cartilage layer thickness of mandibular condyle were decreased. The number of TRAP-positive cells in the condyle, HIF-1a-positive cells, VEGF-positive cells and RANKL-positive cells in the condylar cartilage was significantly increased. In contrast, a reduced expression of OPG protein was observed in the experimental group. On the other hand, NO in growing rats reduced the fiber CSA of the jaw-closing muscles and increased the percentage of MHC-2a in masseter muscles. After unilateral NO, TNF-α expression was upregulated and that of GLUT4 downregulated in masseter and medial temporalis muscles compared with those in control group rats aged 5 and 9 weeks. Our findings suggest that unilateral NO in the growth period affects mandibular morphology and reduces the growth and contraction characteristics of jaw-closing muscles to affect the craniofacial development with changing GLUT4 and HIF-1α expression.
Free Research Field	矯正歯科学
Academic Significance and Societal Importance of the Research Achievements	矯正歯科臨床において、下顎骨の後方位を伴う下顎後退症は、治療が困難となる場合が多く、顎顔面外科手術を併用することも少なくない。現時点では、予防矯正歯科治療のバリエーションは決して多くなく、顎顔面領域に留まらず、鼻疾患へのアプローチが、今後の予防矯正治療の一助となることが期待される。今回の研究結果より、成長期の鼻呼吸障害に伴う下顎骨形態および咀嚼筋の筋組成変化に関して、組織生化学的な観点から新たなメカニズムが解明された。これらの結果は、矯正歯科のみならず、顎顔面外科や耳鼻科、呼吸器内科領域における今後の臨床の発展に大きく寄与するものと考えられた。