Mitigation of Radiation-Induced Gastrointestinal System Injury by Melatonin: A Histopathological Study

The current study aimed to investigate the potential role of melatonin in the mitigation of radiation-induced gastrointestinal injury.Organs of the gastrointestinal system such as the intestines, colon, duodenum, ileum etc. are sensitive to ionizing radiation. Mitigation of radiation-induced gastrointestinal injury is an interesting topic in radiobiology and a life-saving approach for exposed persons after a radiation event or improving the quality of life of radiotherapy patients.The study aimed to find the possible mitigation effect of melatonin on radiation-induced damage to the small and large intestines.40 male mice were randomly assigned into four groups namely G1: control, G2: melatonin treatment, G3: whole-body irradiation, and G4: melatonin treatment after whole-body irradiation. A cobalt-60 gamma-ray source was used to deliver 7 Gy to the whole body. 100 mg/kg melatonin was administered orally 24 h after irradiation and continued for 5 days. Thirty days after irradiation, histopathological evaluations were performed.The whole-body irradiation led to remarkable inflammation, villi shortening, apoptosis and damage to goblet cells of the small intestine. Furthermore, moderate to severe inflammation, apoptosis, congestion, crypt injury and goblet cell damage were reported for the colon. Treatment with melatonin after whole-body irradiation led to significant mitigation of radiation toxicity in both small and large intestines.Melatonin could mitigate intestinal injury following whole-body exposure to radiation. Treatment with melatonin after an accidental exposure to radiation may increase survival via mitigation of damages to radiosensitive organs, including the gastrointestinal system.