Japan Radiation Research Society
| Autor: | Tomomi Kurashige, Hisayoshi Kondo, Shiro Miura, Mutsumi Matsuu-Matsuyama, Masahiro Nakashima, Kumio Okaichi, Kazuko Shichijo |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Male
Aging medicine.medical_specialty DNA damage Health Toxicology and Mutagenesis Thyroid Gland Apoptosis Biology Radiation Dosage Radiation Tolerance Serine X-ray Radiation Ionizing Internal medicine medicine Autophagy Animals Radiology Nuclear Medicine and imaging Radiosensitivity Rats Wistar Thyroid cancer Thyroid Radiation Dose-Response Relationship Radiation medicine.disease Rats Blot Endocrinology medicine.anatomical_structure Immunohistochemistry Rat p53 binding protein 1 Apoptosis Regulatory Proteins Whole-Body Irradiation |
| Zdroj: | Journal of Radiation Research |
| ISSN: | 0449-3060 |
| Popis: | Exposure to ionizing radiation during childhood is a well-known risk factor for thyroid cancer. Our study evaluated the effect of age on the radiosensitivity of rat thyroid glands. Four-week-old (4W), 7 -week-old (7W), and 8-month-old (8M) male Wistar rats were exposed to 8 Gy of whole-body X-ray irradiation. Thyroids were removed 3-72 h after irradiation, and non-irradiated thyroids served as controls. Ki67-positivity and p53 binding protein 1 (53BP1) focus formation (a DNA damage response) were evaluated via immunohistochemistry. Amounts of proteins involved in DNA damage response (p53, p53 phosphorylated at serine 15, p21), apoptosis (cleaved caspase-3), and autophagy (LC3, p62) were determined via western blotting. mRNA levels of 84 key autophagy-related genes were quantified using polymerase chain reaction arrays. Ki67-positive cells in 4W (with high proliferative activity) and 7W thyroids significantly decreased in number post-irradiation. The number of 53BP1 foci and amount of p53 phosphorylated at serine 15 increased 3 h after irradiation, regardless of age. No increase in apoptosis or in the levels of p53, p21 or cleaved caspase-3 was detected for any ages. Levels of LC3-II and p62 increased in irradiated 4W but not 8M thyroids, whereas expression of several autophagy-related genes was higher in 4W than 8M irradiated thyroids. Irradiation increased the expression of genes encoding pro-apoptotic proteins in both 4W and 8M thyroids. In summary, no apoptosis or p53 accumulation was noted, despite the expression of some pro-apoptotic genes in immature and adult thyroids. Irradiation induced autophagy in immature, but not in adult, rat thyroids. Journal of Radiation Research, 56(3), pp.493-501; 2015 |
| Databáze: | OpenAIRE |
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