Soy isoflavones exert beneficial effects on letrozole-induced rat polycystic ovary syndrome (PCOS) model through anti-androgenic mechanism

• Published in: Pharmaceutical biology Vol. 55; no. 1; pp. 242 - 251
• Main Authors: Rajan, Ravi Kumar, M., Siva Selva Kumar, Balaji, Bhaskar
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 01-01-2017; Taylor & Francis Ltd; Taylor & Francis Group
• Subjects: 17-Hydroxysteroid Dehydrogenases - metabolism; 3-Hydroxysteroid Dehydrogenases - metabolism; Androgen Antagonists - isolation & purification; Androgen Antagonists - pharmacology; Animals; Antioxidants - isolation & purification; Antioxidants - pharmacology; Aromatase; Biomarkers - blood; Blood Glucose - drug effects; Blood Glucose - metabolism; Blood levels; Body weight gain; Cholesterol; Cholesterol - blood; daidzein; Disease Models, Animal; Dose-Response Relationship, Drug; Enzymatic activity; Estradiol - blood; Estrous Cycle - drug effects; Estrus cycle; Female; Follicles; Genistein; Glucose tolerance; Glycine max - chemistry; Isoflavones; Isoflavones - isolation & purification; Isoflavones - pharmacology; Letrozole; Nitriles; oestradiol; oestrogen beta; Ovary - drug effects; Ovary - metabolism; Ovary - pathology; Oxidative stress; Oxidative Stress - drug effects; Peripheral blood; phytoestrogen; Phytoestrogens; Phytoestrogens - isolation & purification; Phytoestrogens - pharmacology; Phytotherapy; Plants, Medicinal; Polycystic ovary syndrome; Polycystic Ovary Syndrome - blood; Polycystic Ovary Syndrome - chemically induced; Polycystic Ovary Syndrome - pathology; Polycystic Ovary Syndrome - prevention & control; Rats, Sprague-Dawley; Soy products; Testosterone; Testosterone - blood; Time Factors; Triazoles; Uterus; Uterus - drug effects; Uterus - metabolism; Uterus - pathology; Weight Gain - drug effects; daidzein; phytoestrogen; oestradiol; oestrogen beta; testosterone; Genistein
• ISSN: 1388-0209; 1744-5116; 1744-5116
• DOI: 10.1080/13880209.2016.1258425

Context: Soy is the main source of phytoestrogens, which has long been used as traditional food. One major subtype of phytoestrogens includes isoflavones and they are scientifically validated for their beneficial actions on many hormone-dependent conditions.
Objective: The present study examines the effect of soy isoflavones on letrozole-induced polycystic ovary syndrome (PCOS) rat model.
Materials and methods: PCOS was induced in Sprague-Dawley rats with of 1 mg/kg letrozole, p.o. once daily for 21 consecutive days. Soy isoflavones (50 and 100 mg/kg) was administered for 14 days after PCOS induction. Physical parameters (body weight, oestrous cycle determination, ovary and uterus weight) metabolic parameters (oral glucose tolerance test, total cholesterol), steroidal hormone profile (testosterone and 17β-oestradiol), steroidogenic enzymes (3β-hydroxy steroid dehydrogenase (HSD) and 17β-HSD), oxidative stress and histopathology of ovary were studied.
Results: Soy isoflavones (100 mg/kg) treatment significantly altered the letrozole-induced PCOS symptoms as observed by decreased body weight gain (p < 0.05), percentage diestrous phase (p < 0.001), testosterone (p < 0.001), 3β-HSD (p < 0.01) and 17β-HSD (p < 0.001) enzyme activity and oxidative stress. Histological results reveal that soy isoflavones treatment in PCOS rats resulted in well-developed antral follicles and normal granulosa cell layer in rat ovary.
Discussion: Treatment with soy isoflavones exerts beneficial effects in PCOS rats (with decreased aromatase activity) which might be due to their ability to decrease testosterone concentration in the peripheral blood.
Conclusion: Analysis of physical, biochemical and histological evidences shows that soy isoflavones may be beneficial in PCOS.