Objective: To analyze the effects of melatonin on vascular endothelial growth factor A (VEGF-A) expression and follicle reserve in rat ovary.
Materials and methods: A total of 45 female Wistar rats were used in the present study. Rats were divided into three groups: group 1 (control), group 2 (vehicle), and group 3 (melatonin). Rats in the melatonin group were treated with an intraperitoneal injection of melatonin at a dose of 50 mg/kg/day for 56 days. We investigated VEGF-A expression in rat ovary in all the groups using Western blot and reverse transcription-polymerase chain reaction. Histopathological parameters were evaluated using light microscopy.
Results: The number of atretic follicles was significantly lower in the melatonin treatment rats than in the control rats (p<0.05); however, the number of antral follicles was significantly higher in the former (p<0.05). Additionally, we observed a weak immunoblot stain in the melatonin group for VEGF-A protein. Interestingly, melatonin treatment induced a significant decrease in VEGF-A expression in the ovary of group 3 rats (p<0.05), whereas no such difference was observed between group 1 and group 2 rats (p>0.05).
Conclusion: The present study demonstrates that the protective effect of melatonin on the degeneration of follicles in rat ovary is reduced by decreasing the VEGF-A expression. These results suggest that melatonin is effective against follicular atresia and preserves antral follicles, thus, offering a therapeutic advantage in clinical use.
Keywords: Melatonin; antral follicle; atresia; vascular endothelial growth factor A (VEGF-A).