Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences and Health Services, Tehran, Iran.
Department of Biosciences and Biotechnology, Malek-Ashtar University of Technology, Tehran, Iran.
J Cancer Res Ther. 2020 Dec;16(Supplement):S59-S63. doi: 10.4103/jcrt.JCRT_370_18.
The objective of this study is to observe the effect of 100-mg melatonin in reducing the levels of double-strand breaks (DSB) induced by 10 mGy and 100 mGy X-ray in peripheral lymphocyte applying H2AX immunofluorescence microscopy and comparing the different efficacies of melatonin ingestion 1 and 2 h before irradiation.
Informed consent was obtained from five healthy males, nonathlete, and nonsmoking human volunteers aged between 25 and 35 years. Each volunteer was given a single oral dose of 100 mg melatonin at 9 a.m. Blood samples were collected in vacutainer tubes (without any preservative to separate the serum, and with heparin as an anticoagulant for separating leukocytes for in vitro exposure to gamma radiation) 5-10 min before then 1 and 2 h after melatonin ingestion. Afterward, each sample was subdivided into nonirradiated and irradiated groups (10 mGy and 100 mGy). After irradiation, lymphocytes of samples were separated. The isolated lymphocytes in each group were permeabilized for DSB assessment and stained against the phosphorylated histone variant γH2AX.
Melatonin ingestion 1 and 2 h before irradiation caused a significant reduction in γH2AX foci. Results further indicate that the change in ingestion of melatonin from 1 to 2 h before exposure had no significant effect. In addition, melatonin administration showed no side effects.
The present study showed that melatonin will prove effective in radioprotection against ionizing radiation (IR)-induced DNA damage in human lymphocytes. Our results suggest ingestion of 100-mg melatonin by patients before exposure to IR in radiology.
本研究旨在观察 100 毫克褪黑素对 10 mGy 和 100 mGy X 射线诱导外周血淋巴细胞双链断裂（DSB）的影响，并比较照射前 1 小时和 2 小时服用褪黑素的不同效果。
从 5 名年龄在 25 岁至 35 岁之间的健康男性、非运动员和不吸烟的志愿者中获得知情同意。每位志愿者在上午 9 点口服 100 毫克褪黑素。在服用褪黑素前 5-10 分钟、服用后 1 小时和 2 小时采集血样，置于无防腐剂的真空采血管中（用于分离血清），肝素抗凝管（用于分离白细胞，进行体外γ 射线照射）。之后，每个样本分为未照射组和照射组（10 mGy 和 100 mGy）。照射后，分离淋巴细胞。用 γH2AX 抗体对各组分离的淋巴细胞进行免疫荧光染色，检测 DSB。
照射前 1 小时和 2 小时服用褪黑素均可显著减少 γH2AX 焦点。结果进一步表明，照射前 1 小时和 2 小时服用褪黑素的时间变化没有显著影响。此外，褪黑素的服用没有显示出任何副作用。
本研究表明，褪黑素对人淋巴细胞电离辐射（IR）诱导的 DNA 损伤有防护作用。我们的结果提示，在放射科进行 IR 照射前，患者可服用 100 毫克褪黑素。
