Aims: The current study aimed to investigate the potential role of melatonin in the mitigation
of radiation-induced gastrointestinal injury.
Background: 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.
Objective: The study aimed to find the possible mitigation effect of melatonin on radiation-induced
damage to the small and large intestines.
Methods: 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.
Results: 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.
Conclusion: 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.