Melatonin administration in testicular damage caused by low and high-dose rate radiotherapy: An experimental study

Objective This study aimed to explore the radioprotective effect of melatonin against acute testicular injury caused by low- and high-dose-rate radiotherapy in rats. Materials and methods A total of 40 12-week-old adult male rats were divided into 5 groups (n = 8). Group 1 comprised control rats who were not subjected to any procedures. A single dose of 8 Gy (Gy) radiotherapy was administered to the abdominopelvic regions of Group 2 (low-dose rate radiotherapy (LDRR) group) and Group 4 (high-dose rate radiotherapy (HDRR) group) rats at dose rates of 400 MU/min and 1400 MU/min, respectively. A single dose of 8 Gy radiotherapy was administered to Group 3 (low-dose rate radiotherapy + melatonin (LDRR + MEL) group) and Group 5 (high-dose rate radiotherapy + melatonin (HDRR + MEL) group) rats at dose rates of 400 MU/min and 1400 MU/min, respectively. Following this, 50 mg/kg/intraperitoneal melatonin was given to the rats 15 min before radiotherapy. The subjects were sacrificed 48 h after radiotherapy. Histological, immunohistochemical, immunofluorescence, and biochemical analyses of testicular tissue samples were performed. Results As a result of comparing the FF and FFF radiotherapy groups with the control group, a statistically significant difference was observed in histopathological, biochemical, immunohistochemical and immunofluorescent parameters (p < 0.001). An improvement in these parameters was observed in the groups where melatonin was applied along with radiotherapy (p < 0.001). Additionally, no statistically significant difference was found between FF and FFF dose rates (p > 0.05). Conclusion No significant difference was observed between these low- and high-dose rates of radiotherapy in terms of testicular damage and the effect of melatonin. Further, melatonin may be useful in preventing testicular damage caused by low- and high-dose rate radiotherapy.