Effect of prepubertal and postpubertal long-term exposure to the mild dose of soybean seeds on the tissue and function of thyroid gland in albino rat
The aim of this study is to investigate the effect of long-term exposure to the mild dose of soybean seeds on the tissue and some physiological parameters of the thyroid gland in the prepubertal and postpubertal life stages. Twenty four Sprague-Dawley albino male rats were divided into four groups (n=6); control rats at the prepubertal life stage; prepubertal rats treated with 20% soybean seeds of daily diet for 40 days after the weaning; normal control rats, at the postpubertal stage; and postpubertal rats, were treated with 20% soybean seeds. Morphmetrical, histological and physiological changes were examined. Consumption of mild dose of soybean seeds along the prepubertal life stage showed significant decrease (P<0.05) in the height of follicular cell, significant increase (P<0.05) in the diameter of follicular lumen and ratio of cold follicles, slightly non-significant decline in (T3 and T4) hormones levels and significant increment (P<0.05) in body weight, while at postpuberty, long-term exposure for the same dose of soybean seeds showed significant increase in the height of follicular cell (P<0.05), significant decrease (P<0.05) in the diameter of follicular lumen and ratio of cold follicles caused hyperactivity of the thyroid, significant decline (P<0.05) in (T3 and T4) hormones levels and slightly non-significant increment (P<0.05) in body weight. We concluded that the long-term exposure to the mild dose of the soybean affect adversely the tissue and function of the thyroid at both life stages, pre- and postpuberty.