|导师||信学雷 ; 阿吉艾克拜尔·艾萨|
|关键词||糖尿病 胰岛素抵抗 瘤果黑种草 炎症 氧化应激|
糖尿病威胁人类生命健康，甚至是生命，糖尿病是以胰岛素抵抗为特征，并伴有全身低度炎症反应及高血糖、高血脂、高血压、动脉粥样硬化等症状，是威胁人类的健康和生命的内分泌代谢疾病。抗炎、降糖、降脂、抗氧化是改善胰岛素抵抗的重要手段。黑种草属植物瘤果黑种草，是新疆特有的植物资源，种子是维吾尔族常用的药食部位，对哮喘和支气管炎有治疗作用，是呼吸道疾病常用的维药之一，具有调理胃火、助消化、固齿、抗肿瘤及提高免疫力的作用。本文通过对其粉碎种子经石油醚脱脂，70%乙醇提取浓缩后，经乙酸乙酯萃取得到瘤果黑种草籽乙酸乙酯部位(NEE)，通过体外抗菌实验发现NEE具有抑制金黄葡萄球菌的作用，抑制圈直径为13.5mm，与阳性对照氨苄青霉素14mm效果相当，在LPS诱导RAW264.7巨噬细胞中炎症反应中，NEE具有降低炎症反应的作用，NEE 降低LPS诱导RAW264.7巨噬细胞分泌炎症介质NO、PGE2 及炎性因子IL-6、TNF-α 和MCP-1 的蛋白分泌及基因表达是通过降低IκBα磷酸化而抑制p65进入细胞核以及抑制MAPKs信号通路及引起p65磷酸化和IκBα降解的Akt/GSK-3β信号通路来降低这些炎症因子的表达。经体外降糖抑制剂筛选模型，发现NEE对PTP1B和α-GAA 酶活具有较强的抑制作用，其IC50分别为2.67和365.24μg/mL。NEE促进小鼠L6骨骼肌细胞葡萄糖消耗呈时间与剂量依赖关系，给药50μg/mL作用2h时，L6肌管细胞葡萄糖消耗量最大。昆明小鼠灌胃给药NEE最大药量为40.0g/kg，药后小鼠未见明显异常。在安全毒性范围内，通过高糖高脂饲料喂养，辅以低剂量腹腔注射链脲佐菌（STZ）的方法，建立糖尿病大鼠模型，经高脂饲料NEE灌胃4周，发现NEE能够降低血糖及肝脏中游离脂肪酸的含量，提高糖尿病大鼠肝脏中己糖激酶的活力，同时促进肝糖元和肌糖原的合成。NEE能有效提高肝脏中抗氧化酶系的活力GSH-PX、T-SOD及CAT，并降低氧化产物MDA的能力，并且NEE能降低NO量及iNOS的活力。因此NEE在降低大鼠血糖，提高抗氧化能力的同时保护肝脏免受氧化损伤。综上所述，NEE能改善糖尿病大鼠胰岛素抵抗，其作用机制是通过降低炎症反应，降低血糖，降低肝脏游离脂肪酸，提高肝脏中己糖激酶和抗氧化酶活力。
Diabetes is an endocrine metabolic disease that threatens human’s health and even life. Type 2 diabetes which was characterized by insulin resistance and accompanied by systemic low- grade inflammation and hyperglycemia, hyperlipidemia, hypertension, atherosclerosis and other symptoms, and mainly caused by obesity. Therefore, anti-inflammatory, hypoglycemic, lipid-lowering and antioxidant are important means of improving insulin resistance. The Nigella glandulifera Freyn, belongs to the family of the Ranunculaceae, is widely distributed in Xinjiang China. The seeds have been well-known as a Uighur’s traditional food preservative as well as a remedy for the treatment of respiratory diseases like asthma and bronchitis. In this study, we got the NEE through the powder of skimmed seeds extracted with 70% EtOH and the fractions were dissolved in water and extracted by ethyl acetate. We found that NEE has ability of anti staphylococcus aureus with its inhibition diameter circle of 13.5mm, and we elucidated the mechanism of anti-inflammation in LPS-induced RAW264.7 cells. We found strong inhibition effect of NEE on PTP1B, the IC50 was 2.67μg/mL. Then, we set type II diabetes mellitus model by high sugar, high fat feed, supplemented by intraperitoneal injection of low dose chain urea with bacteria (STZ), and the NEE lavage 4 weeks to observe the NEE in of rat blood sugar, and detect the rat liver glycogen and muscle glycogen, free fatty acid content in the liver and the effects of antioxidant enzymes, explore how NEE improve insulin resistance of type 2 diabetes rats. In vitro bacteriostasis experiment, NEE inhibit the By using Elisa and RT-PCR, the result showed that NEE can inhibit the secretion of inflammatory mediators NO and PGE2, proinflammatory cytokines IL-6 and TNF-α, chemokines like MCP-1both at gene and protein levels.and. By prevention of IκBα phosphorylation and degradation, NEE reduced the translocation of the p65 into the nucleus. NEE attenuated the phosphorylation of AKT and GSK-3β which caused the p65 nuclear translocation. Furthermore, NEE dose-dependently inhibited the phosphorylation of MAPKs including ERK1/2, JNK and p38. In addition, NEE also can interference of arachidonic acid metabolism by inhibiting COX-2 signaling cascade who plays an important role of anti-inflammatory, and reduce the secretion of PGE2 levels in the body. In improving L6 skeletal muscle cells insulin resistance experiments, we found NEE improve insulin resistance in a time and dose-dependence, incubating in 50 μg/mL NEE for 2 h, the glucose consumption reached the highest in myotube. Filled Kunming mice stomachs of mice with NEE maximum dose of 20.0 g/kg, no obvious abnormity were seen in mice. NEE significantly reduce the blood sugar, and the effect is better than that of positive drug metformin. NEE can increase the ability of the liver and muscle taken sugar by improving diabetic rats hexokinase activity in hepatic, and glycogen content increased in liver and muscle. In addition, NEE lowered the content of free fatty acids in the liver. NEE can effectively improve the liver antioxidant enzymes; GSH-PX, T-SOD and CAT, and can reduce the oxidation products of malondialdehyde (MDA), in addition, the NO level was reduced through the inhibition of iNOS activity by NEE. However, NEE has no significant change on TNOS. That means NEE reduced blood sugar, and improve the antioxidase activity meantime it can protect the liver from oxidative damage of diabetic rats. Collectively, NEE has obvious hypoglycemic effect in diabetic rats. The possible of mechanism of hypoglycemic could be by lowering inflammation, improve the liver hexokinase and antioxidant enzymes activity.
|谢连珍. 瘤果黑种草籽提取物改善胰岛素抵抗作用及机制研究[D]. 北京. 中国科学院大学,2015.|
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