Age-dependent effects on radiation-induced carcinogenesis in rat thyroid

2016 Fiscal Year Final Research Report

• Project/Area Number: 26340026
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Risk sciences of radiation and chemicals
• Research Institution: Nagasaki University
• Principal Investigator: MATSUYAMA Mutsumi (松鵜睦美) 長崎大学, 原爆後障害医療研究所, 助教 (00274639)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 甲状腺濾胞上皮細胞 / ラット / 放射線 / 発がん / オートファジー / DNA損傷応答

Outline of Final Research Achievements

To clarify the age-dependent effects to radiation-induced thyroid carcinogenesis, we examined the incidence of radiation-induced thyroid tumor, the change of DNA damage response, the expression of autophagy-related molecule of tumor tissue of immature 4-week old (4W), adult 4-month (4M), and 7 month (7M) rats after 8 Gy X-ray irradiation. The incidence of thyroid tumor was 0, 14.3 and 16.7 % in non-irradiated, and 61.9, 63.6 and 33.3 % in irradiated 4W, 4M and 7M rats respectively. It has been found that the various types of thyroid tumor were occurred multiple in young irradiated rats. At 1 month, the number of 53BP1 foci, cell death and proliferating cells of irradiated group in young rats were higher than non-irradiated rats, and at 12 month these value was decreased to control level in both group. The expression of LC3 and p62 in the poorly differentiated carcinoma and the gene expression of Atg5 and Atg4b in medullary carcinoma of young irradiated rats were decreased.

Free Research Field

放射線生物学