Department of Medical Physics, Tehran University of Medical Sciences (TUMS), International Campus, Tehran 1416753955, Iran.
Research Center for Molecular and Cellular Imaging, TUMS, Tehran 1416753955, Iran.
Medicina (Kaunas). 2019 Jun 25;55(6):308. doi: 10.3390/medicina55060308.
Radiation enteritis is a common side effect after radiotherapy for abdominal and pelvic malignancies. The aim of the present study was to investigate the protective effect of melatonin, known for its free radical scavenging ability, against radiotherapy-induced small intestinal oxidative damage. Thirty male Wistar rats were randomly assigned to six groups (5 rats in each) as follows: Group I (control group) rats received neither radiation nor melatonin; group II rats received only 8 Gy single dose of gamma radiation to their abdomen and pelvis regions; group III (administered with only 50 mg/kg melatonin); group IV (administered with only 100 mg/kg melatonin); group V (50 mg/kg melatonin + 8 Gy radiation), group VI (100 mg/kg melatonin + 8 Gy radiation). All rats were sacrificed after 5 days for biochemical assessments of their intestinal tissues. Treatment with melatonin post irradiation significantly reduced malondialdehyde (MDA) levels as well as increased both superoxide dismutase (SOD) and catalase (CAT) activities of the irradiated intestinal tissues. In addition, melatonin administration with different doses pre irradiation led to protection of the tissues. Moreover, the 100 mg/kg dose was more effective compared to 50 mg/kg. The results of our study suggest that melatonin has a potent protective effect against radiotherapy-induced intestinal damage, by decreasing oxidative stress and increasing antioxidant enzymes. We recommend future clinical trials for more insights.
放射性肠炎是腹部和骨盆恶性肿瘤放射治疗后的常见副作用。本研究旨在探讨褪黑素（因其具有清除自由基的能力而闻名）对放射诱导的小肠氧化损伤的保护作用。
30 只雄性 Wistar 大鼠被随机分为六组（每组 5 只）：组 I（对照组）大鼠既未接受放射治疗也未接受褪黑素治疗；组 II 大鼠仅接受 8 Gy 单次腹部和骨盆区域γ射线照射；组 III（仅给予 50mg/kg 褪黑素）；组 IV（仅给予 100mg/kg 褪黑素）；组 V（50mg/kg 褪黑素+8Gy 辐射），组 VI（100mg/kg 褪黑素+8Gy 辐射）。所有大鼠在 5 天后接受安乐死，以评估其肠道组织的生化指标。
照射后给予褪黑素治疗可显著降低丙二醛（MDA）水平，并增加照射肠组织中超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的活性。此外，照射前给予不同剂量的褪黑素也可保护组织。而且，100mg/kg 剂量比 50mg/kg 更有效。
我们的研究结果表明，褪黑素通过降低氧化应激和增加抗氧化酶对放射诱导的肠道损伤具有很强的保护作用。我们建议进行更多临床试验以获得更深入的了解。
