花卷茶提取物对高胆固醇血症大鼠血脂和内皮功能的影响

Effect of the extract of Hua-juan tea on blood lipids and endothelial function in hypercholesterolemic rats

目的研究花卷茶提取物对高胆固醇血症大鼠血脂和内皮功能的影响及机制。方法雄性SD大鼠高脂饲养4周诱发高胆固醇血症,其中实验组在高脂饲料饲养2周后开始每日灌胃给予不同剂量的花卷茶系列之十两茶水提物(50、100和200mg.kg-1),持续2周。实验结束后,颈动脉取血测定血脂、一氧化氮(NO)、非对称二甲基精氨酸(ADMA)和丙二醛(MDA)含量;分离胸主动脉检测血管内皮依赖性舒张功能。结果十两茶提取物能呈剂量依赖性降低高脂血症大鼠血清总胆固醇和低密度脂蛋白及甘油三酯水平。十两茶提取物能显著改善高脂所诱导的血管内皮舒张功能障碍,降低血浆ADMA和MDA含量以及增加NO水平,且呈剂量依赖性。结论花卷茶系列之十两茶提取物具有降低血脂和保护血管内皮功能作用,其作用与抑制脂质过氧化、调节ADMA/NO系统有关。

Objective To investigate the effect of the extract of Hua-juan tea on blood lipids and endothelial function in hypercholesterolemic rats. Methods Male SD rats were fed for 4 weeks with food containing cholesterol to induce hypercholesterolemia. The experimental group were orally treated with 3 doses of the extract of Shi-liang tea （ 50, 100 or 200 mg · kg^-1 per day） during the last 2 weeks of the experiment. At the end of the experiment, blood samples were collected to measure the plasma levels of nitric oxide （NO）, asymmetric dimethylarginine （ADMA） and malondialdohyde （MDA）, The thoracic aortas were isolated to determine endothelium-dependent vasodilator response. Results The extract of Shi-liang tea could dose-dependently decrease the plasma levels of total cholesterol, low-density lipoprorein and triglyceride in hypercholesterolemic rats. Such treatment could improve the endothelium-dependent vasodilator response and decrease the plasma levels of ADMA and MDA as well as increase the NO content. Conclusion The extract of shi-liang tea may lower the blood lipids and protect the endothelial function, and its effect may be related to inhibiting the peroxidation and modulating ADMA/NO system.