Abstract
Abstract
Background: The study was planned to explain the interactions of isoflavones with estrogen receptors alpha (ERα), beta (ERβ) and vascular endothelial growth factor (VEGF) expressions in ovarian and uterine tissues during different stages of estrous cycle of regular cyclic female Wistar rats.
Methods: Thirty-two regular cyclic females were divided equally into control group: fed casein-based diet and isoflavones group: fed casein-based diet and gavaged 50 mg/kg/day soy isoflavones extract 40%. Regularity of estrus cycles was monitored. Final body weight (FBW), weight gain (BWG), ovarian and uterine weights were estimated. Histopathology and immunohistochemistry for ERα, ERβ and VEGF in ovarian and uterine tissues were performed.
Results: All females (100 %, n=16) in control group showed regularity in estrous cycle compared to 62.5% (n=10) in isoflavones group. Estrus and diestrus phases revealed prolongation and shortening in isoflavones rats than control, respectively. Non-significant variation was noted in the duration of the whole cycle of both groups. FBW and BWG significantly decreased however, ovarian and uterine weights increased significantly in all estrous phases of isoflavones group than control. Histopathology demonstrated increase in number of follicles/ ovaries besides, hyperplasia and proliferation of luminal epithelium with hydropic degeneration in isoflavones group. Also, uterine connective tissue stroma showed edema in isoflavones group during all estrous phases. Immunostaining percentages of ERα, ERβ and VEGF protein expression significantly elevated in isoflavones group during all estrous phases.
Conclusion: Isoflavones induced irregularity of estrous cycle that encountered by increased and altered ERα, ERβ and VEGF expressions in ovarian and uterine tissues.

Key words: ERα • ERβ • Estrous cycle • Isoflavones • VEGF