Tissue response by calorie restriction after radiation exposure.

2019 Fiscal Year Final Research Report

• Project/Area Number: 19K21560
• Project/Area Number (Other): 18H06498 (2018)
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund (2019); Single-year Grants (2018)
• Review Section: 1101:Environmental analyses and evaluation, environmental conservation measure and related fields
• Research Institution: Nagasaki University
• Principal Investigator: NAKAYAMA Takafumi 長崎大学, 原爆後障害医療研究所, 助教 (80829440)
• Project Period (FY): 2018-08-24 – 2020-03-31
• Keywords: カロリー制限 / 放射線発がん / オートファジー

Outline of Final Research Achievements

Mice were exposed to 3.8 Gy X-rays at 1 week of age. From 7 weeks of age, both the control and X-irradiated groups were fed either a standard diet equivalent in caloric intake to ad libitum feeding or the diet with calorie limited by around 30%. It was found that calorie restriction (CR) suppressed body weight increase and the incidence of radiation-induced tumors. Since autophagy is a possible factor related to CR and carcinogenesis, I analyzed the expression of autophagy related proteins (LC3 and p62) after CR using immunofluorescence and western blotting. The results indicated that CR increased both p62 immediately after CR and LC3 after long-term restriction. But overall autophagy activity seemed to be unchanged, suggesting that autophagy is not involved in the suppression of radiation-induced carcinogenesis by CR.

Free Research Field

放射線生物学

Academic Significance and Societal Importance of the Research Achievements

本研究はカロリー制限による放射線発がんに対する抑制効果を改めて示し、長期のカロリー制限とオートファジー関連タンパク質との関係性を解析したことで、未だ完全には明らかになっていないカロリー制限による発がん抑制メカニズムを解明する一助となったと考えられる。本研究をもとにカロリー制限による発がんメカニズムの解明を進めることで、将来的にはカロリー制限を行わずともがん抑制メカニズムに働きかける薬剤の開発や、放射線治療等の医療被ばくによる二次がんを含めた発がんに対して効果的な予防法の創出に繋がる事が期待される。