Protective effects of melatonin agonist on radiotherapy-induced ovarian damage in rats

Objective: To investigate whether melatonin agonist has protective effects on radiotherapy-induced ovarian damage in rats. Methods: Twenty-four SD rats were divided into 4 groups, receiving normal saline (n=6), 200 cGy radiation + normal saline (n=6), 200 cGy radiation + MT (50 mg/kg) (n=6) and 200 cGy radiation + MT (100 mg/kg) (n=6), respectively. All rats were decapitated at two weeks after radiotherapy. Hydroxyl free radical (center dot OH) levels in blood were detected as the indicator of free radical damage. Levels of serum follicle-stimulating hormone (FSH), estradiol (E2) and the number of follicles were measured as the indicators of ovarian reserve, mitochondrial membrane potential (Delta Psi), cytochrome C (cyt c) levels and caspase3 activity were assayed as indicators of mitochondrial pathway. Results: Radiotherapy caused a significant increase in the levels of center dot OH, FSH, cyt c and the activity of caspase3, meanwhile the level of E2, the number of follicles and.. decrease in the Rad group (P<0.05); however in Rad + MT group, these changes were abrogated (P<0.05). Conclusion: melatonin can diminish radiotherapy-induced ovarian damage in female rats, it may be related to the mechanism that MT inhibit mitochondrial pathway induced by radiation.