Abstract The purpose of the present study was to investigate the acute period radioprotective effect of melatonin (Mel) against radiation-iomnduced tissue damage in thyroid gland of rats using thyroid gland scintigraphy imaging. Forty-eight Sprague Dawley female rats were divided into six groups; the control group, melatonin treatment group, low dose rate (LDR-RT), high dose rate (HDR-RT) only radiotherapy groups and radiotherapy plus melatonin groups, (LDR-RT) + Mel and (HDR-RT) + Mel. The head and neck region of each rat was irradiated with single dose of 16 Gy at 6 MV X-ray in FF and FFF beam mode. Melatonin was administered at a single dose of 10 mg/kg through intraperitoneal injection, 15 min prior to radiation exposure. Functional evaluation of the thyroid glands were made using scintigraphy imaging before and after radiotherapy. Statistically significant difference was not observed in thyroid gland to background ratio (T/B) for all experimental rat groups before exposure (p = 0.379). However, when acute effects of irradiation are considered after radiotherapy T/B ratio showed a significant difference (p We showed that melatonin administered before radiotherapy provided significant protective effect against acute rat thyroid gland dysfunction caused by single dose LDR-RT and HDR-RT.

中文翻译：

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褪黑激素对头颈部放疗高剂量率X线致急性甲状腺损伤的作用

摘要 本研究的目的是利用甲状腺闪烁显像研究褪黑激素（Mel）对大鼠甲状腺辐射诱导组织损伤的急性期辐射防护作用。四十八只 Sprague Dawley 雌性大鼠被分成六组；对照组、褪黑激素治疗组、低剂量率（LDR-RT）、高剂量率（HDR-RT）仅放疗组和放疗加褪黑激素组，（LDR-RT）+Mel和（HDR-RT）+Mel。每只大鼠的头部和颈部区域在 FF 和 FFF 光束模式下用 6 MV X 射线单剂量 16 Gy 照射。在辐射暴露前 15 分钟，通过腹膜内注射以 10 mg/kg 的单剂量施用褪黑激素。在放射治疗前后使用闪烁显像成像对甲状腺进行功能评估。暴露前所有实验大鼠组的甲状腺与背景比 (T/B) 未观察到统计学上的显着差异 (p = 0.379)。然而，当考虑放疗后辐射的急性效应时，T/B 比值显示出显着差异（p 我们表明，放疗前施用的褪黑激素对单剂量 LDR-RT 和 HDR-RT 引起的急性大鼠甲状腺功能障碍提供了显着的保护作用。