单纯性肥胖患者氧化应激与内皮依赖性血管舒张功能的关系

The relationship between oxidative stress and endothelium-dependent vasodilatation in obese subjects

目的研究单纯肥胖患者血清氧化物和抗氧化物水平与内皮依赖性血管舒张功能(EDV)的关系,探讨氧化应激在肥胖患者大血管病变发病机制中的作用。方法采用正常血糖高胰岛素钳夹试验评价受试者外周组织对胰岛素的敏感性,多普勒超声评价EDV,并测定血活性氧(ROS)、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-PX)、谷胱甘肽(GSH)及血游离脂肪酸(FFA)水平。结果肥胖组血ROS、MDA、FFA水平较对照组明显增高,GSH-PX、GSH下降,外周组织葡萄糖利用率明显降低,EDV受损;肥胖患者血清ROS、MDA、FFA水平与EDV显著负相关,GSH-PX、GSH水平与EDV显著正相关。结论不伴有传统心血管危险因素的肥胖患者血清中氧化物水平升高,抗氧化物水平下降,EDV受损,提示血FFA水平升高所导致的氧化应激可能参与肥胖患者大血管病变的发生发展。

Objective To evaluate the relationship of the levels of serum oxide and antioxide with endothelium-dependent vasodilatation（EDV） in obese subjects and to explore the effect of oxidative stress on endothelial dysfunction in obese subjects. Methods 20 euglycemic obese males （Ob） and 13 agematched normal controls （NC） underwent euglycemic hyperinsulinemia clamp study to evaluate the peripheral glucose disposal rate （GDR） in steady-state and brachial artery ultrasound studies to assess the endothelium-dependent vasodilatation （EDV）. The serum levels of ROS, MDA, GSH：PX, GSH and free fatty acids （FFAs） were measured. Results The serum ROS, MDA and FFA concentrations were significantly higher in Ob group than in the controls （P〈0.05）, the GSH-PX, GSH levels were lower in Ob group than in the control The GDR were markedly decreased in Ob group （P〈0.05）. EDV was impaired and the relaxation time was shorter in Ob group than in the control （P〈0. 05）. There was significantly negative correlation of EDV with the serum levels of ROS, MDA, FFA （all P〈0.05）, and positive correlation of EDV with the serum levels of GSH-PX, GSH and EDV （all P〈0.05）. Conclusion As compared with normal control, the levels of serum oxides are increased and antioxides levels are decreased in obese subjects. The EDV is impaired in obese subjects who are without traditional cardiovascular risk factors. The oxidative stress caused by elevated FFA concentration may play a role in endothelial dysfunction in obese subjects.