大豆异黄酮对2型糖尿病围绝经期模型大鼠氧化应激损伤的保护作用及其机制

目的：探讨大豆异黄酮对2型糖尿病围绝经期模型大鼠氧化应激损伤的保护作用，阐明其作用机制。方法：将60只大鼠随机取10只为对照组（n=10），其余大鼠采用高糖高脂饲料喂养及切除双侧卵巢的方法建立2型糖尿病围绝经期大鼠模型，造模成功的46只大鼠随机分为假手术组（n=9），模型组（n=8），低（n=9）、中（n=10）和高（n=10）剂量大豆异黄酮组。假手术组大鼠切除两侧卵巢下方的部分脂肪组织，低、中和高剂量大豆异黄酮组大鼠分别灌胃给予不同剂量（90、180和360 mg·kg^-1）大豆异黄酮，对照组、假手术组和模型组大鼠则灌胃给予等体积生理盐水，连续8周。检测各组大鼠体质量和空腹血糖（FBG）水平，采用ELISA法检测各组大鼠血清雌二醇（E2）、促卵泡生成素（FSH）、促黄体生成素（LH）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）、一氧化氮（NO）、丙二醛（MDA）和活性氧（ROS）水平。结果：与模型组比较，低、中和高剂量大豆异黄酮组大鼠体质量和FBG水平明显升高（P<0.05），血清中E2水平明显升高（P<0.05），血清FSH和LH水平明显降低（P<0.05），血清SOD、GSH-Px和NO水平均明显升高（P<0.05），血清MDA和ROS水平均明显降低（P<0.05）。结论：大豆异黄酮可以调节大鼠血清雌激素水平，提高抗氧化应激能力，对2型糖尿病围绝经期模型大鼠氧化应激损伤有保护作用，且不存在剂量依赖性。

Protective effect of soy isoflavone on oxidative stress injury in perimenopause model rats with type 2 diabetes mellitus

Objective: To investigate the protective effect of soy isoflavone on the oxidative stress injury of the perimenopause model rats with type 2 diabetes mellitus, and to elucidate its mechanism. Methods: Ten rats of all the sixty rats were randomly choosen as control group(n=10).The perimenopause models of rats with type 2 diabetes mellitus were established by feeding high sugar diet and removing both ovaries,and the rest 46 perimenopause model rats were randomly divided into sham operation group(n=9), model group(n=8), low(n=9), medium (n=10)and high(n=10) doses of soy isoflavone groups. The partial adipose tissue below both ovaries of the rats in sham operation group was removed, the rats in low, medium and high doses of soy isoflavone groups were given different doses (90, 180, and 360 mg·kg^-1) of soy isoflavone by gavage, while the rats in control group, sham operation group and model group were given the same volume of normal saline, lasted for 8 weeks. The body weights and the levels of fasting blood glucose (FBG) of the rats in various groups were measured.The levels of serum estradiol (E2), follicle-stimulating hormone (FSH), luteinizing hormone (LH), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), nitric oxide (NO), malondialdehyde (MDA), and reactive oxygen species (ROS) of the rats in various groups were measured by ELISA method. Results: Compared with model group, the body weights and the FBG levels of the rats in low, medium and high doses of soy isoflavone groups were increased significantly (P<0.05); the levels of serum E2 were significantly increased (P<0.05),the levels of serum FSH and LH were significantly decreased (P<0.05), the levels of serum SOD, GSH-Px and NO were significantly increased (P<0.05), and the levels of serum MDA and ROS were significantly decreased (P<0.05). Conclusion: Soy isoflavone can regulate the level of serum estrogen, improve the ability of anti-oxidative stress, and protect the oxidative stress injury in the perimenopause model rats with type 2 diabetes mellitus in a non-dose-dependent manner.