Morphological and functional changes in neonatally X-irradiated thyroid gland in rats
Morphological and functional changes in neonatally X-irradiated thyroid gland in rats
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DOI：
10.1507/endocrj.ej19-0245
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发表时间：
2020-01-01
影响因子：
2
通讯作者：
Nakashima, Masahiro
中科院分区：
文献类型：
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作者：
Fujimoto, Nariaki;Matsuu-Matsuyama, Mutsumi;Nakashima, Masahiro
儿童时期暴露于电离辐射已被认为是甲状腺癌和其他甲状腺疾病的一个风险因素。然而，新生儿辐射暴露对甲状腺形态和功能的影响从未被探讨，尽管其潜在的重要性。对一周龄雄性Wistar大鼠进行6和12戈伊的颈部X射线照射。在2、8和18周龄时检查动物。为了比较，8周龄的大鼠颈部X射线照射在相同的剂量。通过计算机辅助显微镜检查甲状腺组织学，以测量甲状腺滤泡的胶质和上皮面积以及上皮高度。在1周龄时接受颈部X射线照射的大鼠中，甲状腺滤泡的胶体大小在8周龄时以辐射剂量依赖的方式减小。这种形态学变化在18周龄时持续存在。各组间血清总T3、T4水平无显著性差异。8周龄大鼠经X线照射后，血清TSH水平明显升高。甲状腺球蛋白（Tg）mRNA和蛋白表达在18周龄时显著降低，甲状腺过氧化物酶mRNA表达在18周龄时显著升高。在8周龄时X射线照射的大鼠中未观察到这些变化。总之，我们的研究结果清楚地表明，新生大鼠甲状腺对电离辐射敏感，发展特定的形态学变化，其特征是甲状腺滤泡沿着变化，血清TSH水平和甲状腺组织中Tg的表达。
Exposure to ionized radiation in childhood has been recognized as a risk factor for the development of thyroid cancer and possibly for other thyroid disorders. However, the effects of neonatal radiation exposure on thyroid morphology and functions have never been explored despite its potential importance. One-week-old male Wistar rats were subjected to cervical X-irradiation at 6 and 12 Gy. Animals were examined at the ages of 2, 8 and 18 weeks old. For comparison, 8 -weekold rats were cervically X-irradiated at the same doses. Thyroid histology was examined by computer-assisted microscopy to measure areas of colloid and epithelium of thyroid follicles as well as epithelial heights. In rats that received cervical Xirradiation at 1 week old, the colloid size of thyroid follicles decreased at the age of 8 weeks old in a radiation-dose dependent manner. This morphological change was persistently found at 18 weeks old. There were no significant differences in serum total T3 or T4 levels among the groups. Senim TSH levels increased significantly in 8-week-old rats neonatally X-irradiated. Thyroglobulin (Tg) mRNA and protein expressions were significantly decreased in the neonatally-irradiated group while thyroid peroxidase mRNA express increased at 18 weeks old. None of these changes were observed in the rats X-irradiated at 8 weeks old. In conclusion, our results clearly demonstrated that neonatal rat thyroid was sensitive to ionized radiation, developing specific morphological changes characterized by smaller thyroid follicles along with changes in serum TSH levels and Tg expressions in the thyroid tissue.