Subchronic Toxicity Study on Soy Isoflavones in Rats

• Published in: Biomedical and environmental sciences 2009-06, Vol.22 (3), p.259-264
• Main Authors: ZHANG, Wen-Zhong, CUI, Wen-Ming, ZHANG, Xin, WANG, Wei, JIA, Xu-Dong, ZHANG, Xiao-Peng, LI, Ning
• Format: Article
• Language: English
• Subjects: Animals; Dose-Response Relationship, Drug; Drug Administration Schedule; Follicle Stimulating Hormone - blood; Glycine max - chemistry; Isoflavones - administration & dosage; Isoflavones - chemistry; Isoflavones - toxicity; Male; Rat; Rats; Rats, Sprague-Dawley; Soy isoflavone; Subchronic toxicity; Thyroxine - blood; Triiodothyronine - blood; 临床化学检验; 亚慢性毒性; 大豆异黄酮; 应力强度; 无害作用剂量; 组织病理学检查; 雄性大鼠; 高密度脂蛋白胆固醇
• ISSN: 0895-3988; 2214-0190
• DOI: 10.1016/s0895-3988(09)60054-4

Objective To investigate the subchronic toxicity of soy isoflavones （SIF） in male rats. Method Fifty Sprague-Dawley rats were randomly divided into 5 groups, 10 rats per group. SIF were given to rats in different groups by gavage at dose of 0, 0.2, 0.5, 1.5, and 4.5 g/kg bw, respectively for 13 weeks. Clinical manifestations, body weight, and food consumption were observed weekly. At the end of the study, urinalysis, hematology, clinical chemistry, total testosterone, and follicle-stimulating hormone were tested, and histopathological examinations were performed. Results No mortality, ophthalmic abnormalities or treatment-related clinical signs were identified during the study. As compared with the control group, significantly lower body weights and food consumption were observed in 1.5 and 4.5 g/kg bw groups. In clinical chemistry tests, triglyceride was significantly decreased and high-density lipoprotein cholesterol was significantly increased in all SIF-treated groups. Total testosterone levels were significantly lower in 0.50, 1.50, and 4.5 g/kg bw dose groups than in the control group. Microscopic examination showed that the mammary glands exhibited hyperplasia and excreted latex in rats of the 4.5 g/kg bw group. No changes attributable to treatment of SIF in other parameters were found. Conclusion SIF at high dosages caused significant endocrine disruption in male rats. The no observed adverse effect level （NOAEL） of SIF to male rats in this study is considered to be 0.20 g/kg bw.