Effect of soy milk on circulating ۱۷- β estradiol, number of neurons in cerebral cortex and hippocampus and determination of their ratio in neonatal ovariectomized rats

This study was conducted to evaluate the effect of soy milk on serum ۱۷- β estradiol level and number of neurons in cerebral cortex and hippocampus as well as determination of the ratio of neurons in cortical and hippocampal regions in neonatal ovariectomized rats. Thirty female rats (one day old) were divided into six groups of five. At day ۷, ovariectomy surgery was performed in four groups and two other groups were assumed as sham and control groups. Three groups of ovareictomaized rats were fed with soy milk at the doses of ۰.۷۵, ۱.۵۰ and ۳.۰۰ mL kg-۱ per day since they were ۱۴. At day ۶۰, the blood samples were collected to measure the۱۷- β estradiol concentration, and then the brain of rats were prepared for histological studies. The serum ۱۷- β estradiol level significantly increased in ovariectomized rats fed with soy milk compared to ovariectomized rats with no soy milk supplementation. In addition, the results showed that soy milk significantly increased the number of neurons in CA۱, CA۲ and dentate gyrus regions of hippocampus and granular layer of cerebral cortex in ovariectomized rats, whereas there was no significant change in number of neurons in CA۳ zone of hippocampus and molecular, pyramidal and multiform layers of cerebral cortex in ovariectomized rats fed with soy milk. The ratio of cerebral cortex neurons to hippocampal neurons had no significant changes among the experimental groups.

Keywords:

۱۷- β estradiol , Hippocampus , neuron , Rat , Soy milk