Wang Lei, Li Xinliang, Zhang Yanqi, Huang Yongpan, Zhang Yinzhuang, Ma Qilin
Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Changsha, China.
Department of Pharmacology, Institue of Chinese Medicine, Hunan Academy of Chinese Medicine, Changsha, China.
J Cell Biochem. 2019 May;120(5):7323-7332. doi: 10.1002/jcb.28006. Epub 2018 Nov 19.
Oxymatrine (OMT) is the major quinolizidine alkaloid extracted from the root of Sophora flavescens Ait (the Chinese herb Kushen) and exhibits diverse pharmacological actions. In this study, we investigated the effects of OMT on diabetes-associated aortic endothelial dysfunction in a rat model of diabetes and its mechanisms.
Male Sprague-Dawley rats were randomly divided into five groups: control, diabetic rats, diabetic rats treated with OMT (60, 120 mg/kg per day, by gavage), and diabetic rats treated with metformin (20 mg/kg per day, by gavage). The serum fasting blood glucose, insulin, total cholesterol, triglyceride, and nitric oxide (NO) levels were determined with commercial kits. Biochemical indices reflecting oxidative stress, such as malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were analyzed with commercial kits. Mitochondrial reactive oxygen species 2',7'-dichlorofluorescein diacetate (DCFH-DA) was measured by fluorescence microscopy. Histological analyses were conducted to observe morphological changes. Western blot analysis was applied to detect the expression levels of eNOS and NOX4. Reverse transcription polymerase chain reaction was used to detect the expressions of eNOS and NOX4 messenger RNA (mRNA).
The diabetic rats exhibited markedly reduced body weight and increased plasma glucose levels. Moreover, the diabetic rats showed oxidative stress (significantly increased MDA and decreased SOD, CAT, GSH-Px, and serum NO levels). Hyperglycemia caused significant endothelial injury and dysfunction, including vasodilative and histologic changes in the diabetic rats. The expressions of phospho-eNOS protein and mRNA were significantly decreased, while the NOX4 protein expression was increased in the aortas of the diabetic rats. All of these diabetes-induced effects were reversed by OMT in the diabetic rats.
The OMT treatment ameliorates diabetic endothelial dysfunction through enhanced NO bioavailability by upregulating eNOS expression and downregulating expression of NOX4.
氧化苦参碱（OMT）是从苦参（中药苦参）根中提取的主要喹诺里西啶生物碱，具有多种药理作用。在本研究中，我们研究了OMT对糖尿病大鼠模型中糖尿病相关主动脉内皮功能障碍的影响及其机制。
将雄性Sprague-Dawley大鼠随机分为五组：对照组、糖尿病大鼠、用OMT治疗的糖尿病大鼠（每天60、120mg/kg，灌胃）和用二甲双胍治疗的糖尿病大鼠（每天20mg/kg，灌胃）。用商业试剂盒测定血清空腹血糖、胰岛素、总胆固醇、甘油三酯和一氧化氮（NO）水平。用商业试剂盒分析反映氧化应激的生化指标，如丙二醛（MDA）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽过氧化物酶（GSH-Px）。通过荧光显微镜测量线粒体活性氧2',7'-二氯荧光素二乙酸酯（DCFH-DA）。进行组织学分析以观察形态学变化。应用蛋白质印迹分析检测内皮型一氧化氮合酶（eNOS）和NADPH氧化酶4（NOX4）的表达水平。逆转录聚合酶链反应用于检测eNOS和NOX4信使核糖核酸（mRNA）的表达。
糖尿病大鼠体重明显减轻，血糖水平升高。此外，糖尿病大鼠表现出氧化应激（MDA显著升高，SOD、CAT、GSH-Px和血清NO水平降低）。高血糖导致糖尿病大鼠明显的内皮损伤和功能障碍，包括血管舒张和组织学变化。糖尿病大鼠主动脉中磷酸化eNOS蛋白和mRNA的表达显著降低，而NOX4蛋白表达增加。OMT可逆转糖尿病大鼠所有这些由糖尿病引起的效应。
OMT治疗通过上调eNOS表达和下调NOX4表达来增强NO生物利用度，从而改善糖尿病内皮功能障碍。
