葡萄糖对铜离子依赖性低密度脂蛋白氧化的影响。

Ghaffari Mohammad Ali, Mojab Samad

Dept. of Clinical Biochemistry, School of Medical, Ahwaz Jundishapour University of Medical Sciences, Ahwaz, Iran.

Iran Biomed J. 2009 Jan;13(1):59-64.

BACKGROUND

It is well established that oxidative modification of low density lipoprotein (LDL) plays a causal role in human atherogenesis and the risk of atherosclerosis is increased in patients with diabetes mellitus. We examined the in vitro effect of glucose on native and glycated LDL oxidation using copper ion dependent oxidation system.

METHODS

In this study, LDL was isolated from plasma by ultracentrifugation using a single step discontinuous gradient. Native LDL preparations were glycated by glucose and also were oxidized by copper ions. LDL glycation and oxidation levels were estimated by sodium periodate assay and thiobarbituric acid reactive substances (TBARS), respectively. Then, native LDL was incubated with glucose and copper and LDL oxidation was estimated by TBARS. Finally, oxidation of glycated LDL was studied in presence of copper ions by TBARS and relative electrophoretic mobility on polyacrylamide gel.

RESULTS

This study showed that glucose considerably decreased the oxidation of native LDL by copper ions. But oxidation of glycated LDL elevated with presence of copper ions.

CONCLUSION

The results of this investigation show that LDL glycated in vitro is prone to oxidation by copper ions. Thus, promotion of glycated LDL oxidation by glucose is specific for copper ion dependent oxidation and involves increased copper ion reduction. These results provide one mechanism that may enhanced LDL oxidation in diabetes and thus contribute to the pathogenesis of atherosclerosis in diabetic patients.

背景

低密度脂蛋白（LDL）的氧化修饰在人类动脉粥样硬化形成过程中起因果作用，且糖尿病患者动脉粥样硬化风险增加，这一点已得到充分证实。我们使用铜离子依赖性氧化系统研究了葡萄糖对天然LDL和糖化LDL氧化的体外影响。

方法

在本研究中，通过单步不连续梯度超速离心从血浆中分离LDL。天然LDL制剂用葡萄糖进行糖化处理，并用铜离子进行氧化。分别通过高碘酸钠法和硫代巴比妥酸反应性物质（TBARS）评估LDL的糖化和氧化水平。然后，将天然LDL与葡萄糖和铜一起孵育，并用TBARS评估LDL氧化。最后，通过TBARS和在聚丙烯酰胺凝胶上的相对电泳迁移率研究在铜离子存在下糖化LDL的氧化。