Brain microenvironment that determines the direction of degeneration or regeneration of the olfactory bulb projection neurons coupled with the inflammatory status of the nasal cavity

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K07395
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 51030:Pathophysiologic neuroscience-related
• Research Institution: Kyorin University
• Principal Investigator: Hasegawa-Ishii Sanae 杏林大学, 保健学部, 准教授 (40435863)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 鼻腔炎症 / 嗅球 / 精神疾患 / 脳と免疫

Outline of Final Research Achievements

Chronic nasal inflammation can be a risk factor for psychiatric disorders. As the first step to reveal the mechanism, we compared the effects of nasal inflammation and odor deprivation on the olfactory bulb (OB). The results from the animal study using mouse model indicate that the OB was atrophied in both models; nasal inflammation induced the shrinkage of outer layers of the OB with neuroinflammation, while odor deprivation caused the shrinkage of inner layers with no neuroinflammation. The OB recovered from the atrophy when the nasal inflammation subsided, during which the odor input was needed. Next, gut microbiota of mice with nasal inflammation was analyzed by 16S rRNA analysis. Results indicate that microbiota of male, but not female, mice with chronic nasal inflammation was remarkably changed. Thus, nasal inflammation perturbed the homeostasis of the brain and gut microbiota, which might lead to the onset of psychiatric disorders. 953

Free Research Field

実験神経病理学

Academic Significance and Societal Importance of the Research Achievements

嗅球の萎縮は、副鼻腔炎、アルツハイマー病、うつ病、不安障害などの患者で見られ、嗅覚障害の原因となり、患者の生活の質を低下する。本研究は、鼻腔炎症と嗅覚刺激遮断の嗅球における影響の違いを明らかにし、鼻腔炎症による嗅球の萎縮は、炎症が治まり嗅覚刺激が戻れば回復する可能性を示した。また、鼻腔炎症が脳及び腸内細菌叢を乱すことを明らかにし、精神神経疾患発症の原因となる可能性を示唆した。