Soybean, a rich source of phytoestrogens, exhibit estrogen-type bioactivity. The use of dietary soybean as a possible option for the prevention of osteoporosis has raised considerable interest because of the increased concern about the risks associated with the use of estrogen therapy.
The purpose of this study was to compare between the preventive effects of both soybean and estrogen on post ovariectomy osteoporosis in rats.
Forty adult female albino rats were divided into 4 groups. Group 1, served as sham controls. Group 2, served as ovariectomized controls. Group 3, rats were exposed to surgical removal of their ovaries and were given synthetic estrogen (diethylstilbestrol tablets) orally (nasogastric tube) as 0.03mg / kg bw/day (2 weeks post-ovariectomy). Group 4, rats were exposed to surgical removal of their ovaries and soybean was given before food to rats by 3 daily servings as a cup of soybean (50 grams) for each serving 2 weeks after ovariectomy . Bone samples (femurs) were obtained 4, 6 weeks after ovariectomy and sections were prepared for light microscopic (H & E) and electron microscopic examination.
The results revealed that ovariectomy resulted in osteoporotic bone changes with apparent increase in the number and activity (highly folded ruffled border) of osteoclast. Diethylstilbestrol control effectively the osteoporotic bone changes occurred by ovariectomy and decreased the number and activity of osteoclast bone cells while soybean less effectively control the osteoporotic bone changes with apparent increase in the number and activity of oseoblasts.
In conclusions, this study demonstrates that dietary soybean had an important preventive role in osteoprotic changes occurred after ovariectomy and in spite of estrogen is more effective , dietary soybean should be used as a natural safe product to get a satisfactory bone quality after menopause and to avoid the serious effects of prolonged use of estrogen therapy.
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