2022 Fiscal Year Final Research Report

The effects of low dose UV exposure during infancy on the development of atopic dermatitis

Research Project

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Project/Area Number	20K08674
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 53050:Dermatology-related
Research Institution	Kochi University
Principal Investigator	YAMAMOTO Mayuko 高知大学, 教育研究部医療学系臨床医学部門, 助教 (20423478)
Co-Investigator(Kenkyū-buntansha)	中島喜美子高知大学, 教育研究部医療学系臨床医学部門, 准教授 (20403892) 青木奈津子高知大学, 医学部附属病院, 助教 (40457396) 佐野栄紀高知大学, 教育研究部医療学系臨床医学部門, 教授 (80273621)
Project Period (FY)	2020-04-01 – 2023-03-31
Keywords	アトピー性皮膚炎 / 乳児期 / 紫外線暴露
Outline of Final Research Achievements	The purpose of this study was to investigate the effects of UV exposure during infancy on the development of atopic dermatitis. We evaluated a model of atopic dermatitis in hairless mice induced by repeated application of TNCB after repeated exposure to low dose UVB. The UVB irradiated group showed a decrease in clinical score of dermatitis and epidermal thickening compared to the non-irradiated group. Dermatitis was reduced in the late (from 3 to 6 weeks old) irradiated group than in the early (from 3 days to 3 weeks old) irradiated group. The irradiated groups showed decreased expression of IL-4 in the skin lesion. These results suggested that UV exposure may inhibit the subsequent development of dermatitis. However, there was no difference in serum IgE levels between the groups, suggesting that Th2 induction was insufficient. Therefore, it is necessary to conduct a similar study with different haptens in the future.
Free Research Field	医歯薬学
Academic Significance and Societal Importance of the Research Achievements	皮膚において、紫外線照射は、浸潤T細胞のアポトーシス誘導や炎症性サイトカイン減少、ランゲルハンス細胞や肥満細胞数を減じるなどの免疫細胞への作用に加え、表皮分化関連分子や脂質合成の誘導、抗菌ペプチド産生促進などバリア機能への促進的作用が報告されている。また乳幼児において積算紫外線暴露量がアトピー性皮膚炎罹患率と逆相関するとの報告もある。しかし、in vivoにおける証明は存在しない。今回の実験により生後早期からの低用量紫外線暴露が、その後のアトピー性皮膚炎を軽減する可能性が示唆された。適度な紫外線暴露がアトピー性皮膚炎発症を抑制することが証明されれば患者にとって大きな福音となる。