2型糖尿病患者血清脂蛋白氧化易感性及高密度脂蛋白抗氧化能力分析

Oxidative susceptibility of serum lipoproteins and effects of high density lipoprotein against oxidative stress in type 2 diabetes mellitus

目的 :探讨 2型糖尿病患者血清脂蛋白氧化易感性以及高密度脂蛋白抗低密度脂蛋白氧化能力的变化。 方法 :采用密度梯度超速离心分离 5 3例 2型糖尿病患者血清脂蛋白组分 (VL DL、L DL 和 HDL) ,用 A2 34 nm光吸收鉴定脂蛋白氧化易感性 ,硫代巴比妥酸值 (TBARS )分析脂蛋白脂质过氧化程度 ,同时检测 HDL对 L DL氧化的抑制能力 ,并与正常人 (44例 )进行比较。 结果 :2型糖尿病患者 VL DL 、L DL 氧化延滞时间明显缩短 (VL DL:80 .7± 5 .8vs 2 4.3± 4.85 ;L DL :6 0 .0± 4.0 vs 1 7.4± 3.0 1 ,P<0 .0 0 1 ) ,HDL组分对 L DL氧化的抑制能力明显降低 (P<0 .0 1 )。 结论 :2型糖尿病患者 VL DL、L DL 组分氧化易感性提高以及 HDL 抗氧化能力的下降 ,是

Objectives: To investigate the changes in susceptibility of serum lipoproteins to oxidation and the inhibitory effects of high density lipoprotein (HDL) on the oxidation of low density lipoprotein (LDL) in patients with type 2 diabetes mellitus. Methods: Lipoproteins were isolated using density gradient ultra-centrifugation from serum of type 2 diabetes mellitus(n=53) and age-matched normal individuals(n= 44). The degree of lipid peroxidation was estimated using the thiobarbituric acid-reactive substances (TBARS) value and the susceptibilities of lipoproteins to oxidation were assessed by measuring the increase in absorbance at 234 nm due to conjugated diene formation. Lipid levels in both serum and lipoprotein fractions were measured using standard methods. Results: VLDL and LDL obtained from patients with diabetes mellitus showed significant increase in TBARS values (P<0.01 ) and enhanced susceptibility to in vitro oxidation as demonstrated by the significant decrease in lag time (VLDL:80.7±5.8 vs 24.3±4.85; LDL: 60.0±4.0 vs 17.4±3.01, P<0.001). In addition, HDL from diabetes mellitus patients exhibited significantly decrease in inhibitory effect on in vitro oxidation of LDL. Conclusions: The enhanced susceptibility to oxidation in VLDL and LDL fractions and impaired protective effect of HDL against oxidative stress might increase the risk of atherosclerosis in type 2 diabetes mellitus.