Melatonin reduced endometrial hyperplasia induced by estradiol in female albino rats.

Melatonin, the pineal gland hormone, plays a crucial role in regulation of neuroendocrine and defensive functions, free radicals neutralization, and suppresses angiogenesis, proliferation and cancer. The purpose of designing our study is to assess the effect of estradiol benzoate and its combination with melatonin on uteri of female albino rats. For 4 weeks, the present study was conducted on thirty six female rats separated into 3 groups: Control group (rats received the vehicle), EB group (rats were treated by estradiol benzoate (600 μg/kg intramuscular) for induction of endometrial hyperplasia), and EB+Mel group (rats were treated with estradiol benzoate (600 μg/kg) plus melatonin (50 µg/ml) added to drinking water. Melatonin administration reduced estradiol benzoate-induced endometrial hyperplasia and prevented the occurrence of atypia associated with a significant reduction in lipid peroxide level and NF-κB mRNA and a significant rise in immune-expression of caspase-3, interleukin-2 (IL-2) mRNA and total antioxidant levels in uterine tissues. The results demonstrated that melatonin reduced estradiol benzoate action on the endometrium.