Effect of Melatonin on Proliferative Activity and Apoptosis in Spermatogenic Cells in Mouse under Chemotherapy

Objective To investigate the possible protective role of melatonin on the proliferativeactivity, and apoptosis of germ cells in chemotherapy-induced spermiotoxicity.Methods Male adult NMRI mice were divided into four groups. Then each group was divided into two subgroups of a and b. Group A (control): mice received vehicle (1% ethanol)for 5 d. Group B (busulfan): mice received a single dose of 20 mg/kg busulfan. Group C (melatonin): mice received melatonin (10 mg/kg) for 5 d. Group D (busulfan+melatonin): mice received a 5-day course of melatonin (10 mg/kg) following an initial dose of busulfan (20 mg/kg). Evaluations were made using bromodeoxyuridine (BrdU) labeling and in situ TUNEL assay after 5 d (subgroup a) or 35 d (subgroup b). Results Busulfan-treated mice both in subgroups a and b, showed a significant increase in the number of apoptotic cells (P<0.01) and decrease in BrdU labeling index (P<0.01) compared with controls. Melatonin in group C significantly decreased BrdU labeling index compared with the control (P <0.01). Melatonin in group D significantly reduced apoptosis rate and increased BrdU labeling index compared with group B.Conclusion Melatonin may have a protective effect against busulfan-induced testicular damage, partly by decreasing of apoptosis and alteration in proliferative activity of germ cells.