Oxidative stress impairs oocyte quality and melatonin protects oocytes from free radical damage and improves fertilization rate

To examine the effects of melatonin and vitamin E as antioxidants on intrafollicular oxidative stress, some patients were treated with melatonin, some with vitamin E, and some received both melatonin and vitamin E. Eighteen patients undergoing IVF-ET who failed to become pregnant in the previous IVF-ET cycle were enrolled. Four patients were given a 3 mg tablet of melatonin (KAL, Park City, UT, USA) orally at 22:00 hr, 10 patients were given vitamin E (α-tocopherol, 600 mg/day, 200 mg capsule three times a day) orally and 15 patients were similarly given both melatonin and vitamin E. These treatments were carried out from the fifth day of the previous menstrual cycle until the day of oocyte retrieval. Intrafollicular concentrations of melatonin, 8-OHdG and hexanoyl-lysine adduct (HEL, a biomarker of lipid peroxidation) were determined and were compared to the data in the previous IVF-ET cycle (control cycle)