Pre-treatment effect of different doses of soy isoflavones on spatial learning and memory in an ovariectomized animal model of Alzheimer's disease.

The aim of this study was to evaluate the effects of different doses of dietary soy meals (with or without isoflavone) on dementia in ovariectomized (OVX) animal model of Alzheimer's disease. Female Wistar's rats with the exception of intact group were ovariectomized at the first line of study. Animals were divided into 2 main groups: control (c) and pre-treatment groups. Animals in pre-treatment groups received one of five types of diet during four weeks prior Nucleus Basalis Magnocellularis (NBM) electrical lesion normal diet (0), 10 g soy with isoflavone (10), 20 g soy with isoflavone (20), 10 g soy without isoflavone (-10) and 20 g soy without isoflavone (-20) in 30 g daily diet. The spatial learning and memory were tested using Morris water maze after electrical lesion. Rats were trained in water maze to find a hidden escape Platform. Rats received 6 blocks that each block consisted of 3 trials. Following acquisition trials, one probe trial was conducted in which the platform was removed. Soy meal diet (with or without isoflavone) in ovariectomized rats with Alzheimer's disease caused improvement of performance across 18 trials of Acquisition. Our results suggest that soy meal is a potential alternative to estrogen in the prevention and treatment of Alzheimer's disease.