The effect of melatonin and probiotics on radiation-induced enteritis in experimental rat models

Radiotherapy plays an important role in the treatment of tumors, and enteritis is a common side effect of this therapy. The aim of present study was to evaluate the protective effect of melatonin and probiotics on radiation-induced intestinal tissue damage in rats. Histopathological, biochemical and microbiological samples were examined. Thirty-two Wistar Albino rats were randomly distributed into four groups: the control group, only radiotherapy (RT) group, radiotherapy plus melatonin (RT + MEL) groups and radiotherapy plus probiotics (RT + PROB) groups. The abdominal-pelvic region of the experimental rat was irradiated with in a single dose of 16 Gy. The melatonin was administered at a single dose of 50 mg/kg through intraperitoneal injection, 15 min before radiation exposure. The probiotic was administered orally every day to the rats for 5 days starting before radiotherapy. There was a statistically significant changes in histopathological (villus atrophy, mitotic activity, apoptotic index, goblet cell swelling, degenerative changes, atypia) and biochemical (oxidant and antioxidant status, IL-1 beta, IL-6 and TNF- alpha levels) parameters in the small intestine in the radiotherapy group G2 compared to the G1 control group (p < 0.05). However, a significant decrease was observed with the administration of probiotics and melatonin (p < 0.05). In addition, although positive bacterial growth was detected in the mesenteric lymph node of all rats in the radiotherapy group, there was no statistically significant difference between all groups (p > 0.05). Melatonin and probiotics were found to have a potent radioprotective effect against radiotherapy-induced acute small intestinal tissue damage. However, their superiority over each other was not observed.