Rajeswari P, Natarajan R, Nadler J L, Kumar D, Kalra V K
Department of Medicine, University of Southern California, School of Medicine, Los Angeles 90033.
J Cell Physiol. 1991 Oct;149(1):100-9. doi: 10.1002/jcp.1041490113.
Erythrocytes of diabetic subjects (non-insulin dependent) were found to have eight- to ten-fold higher levels of endogenously formed thiobarbituric acid reactive malonyldialdehyde (MDA), thirteen-fold higher levels of phospholipid-MDA adduct, 15-20% reduced Na(+)-K(+)-ATPase activity with unchanged Ca+2-ATPase activity, as compared with the erythrocytes from normal healthy individuals. Incubation of normal erythrocytes with elevated concentrations (15-35 mM) of glucose, similar to that present in diabetic plasma, led to the increased lipid peroxidation, phospholipid-MDA adduct formation, reduction of Na(+)-K(+)-ATPase (25-50%) and Ca+2-ATPase (50%) activities. 2-doxy-glucose was 80% as effective as glucose in the lipid peroxidation and lipid adduct formation. However, other sugars, such as fructose, galactose, mannose, fucose, glucosamine and 3-O-methylmannoside, and sucrose, tested at a concentration of 35 mM, resulted in reduced (20-30%) lipid peroxidation without the formation of lipid-MDA adduct. Kinetic studies show that reductions in Na(+)-K(+)-ATPase and Ca+2-ATPase activities precede the lipid peroxidation as the enzyme inactivation occur within 30 min of incubation of erythrocytes with high concentration (15-35 mM) of glucose, while lipid peroxidation product, MDA appears at 4 hr and lipid-MDA adducts at 8 hr. The lipoxygenase pathway inhibitors, 5,8,11-eicosatriynoic acid and Baicalein (5,6,7-trihydroxyflavone), reduced the glucose-induced lipid peroxidation by 30% and MDA-lipid adduct formation by 26%. Indomethacin, a cyclooxygenase pathway inhibitor, had no discernible effect on the lipid peroxidation in erythrocytes. However, the inhibitors of lipid peroxidation, 3-phenylpyrazolidone, metyrapone, and the inhibitors of lipoxygenase pathways did not ablate the glucose-induced reduction of Na(+)-K(+)-ATPase and Ca+2-ATPase activities in erythrocytes. Erythrocytes produce 15-HETE (15-hydroxy-eicosatetraenoic acid), which is augmented by glucose. These results suggest that the formation of lipoxygenase metabolites potentiate the glucose-induced lipid peroxidation and that the inactivation of Na(+)-K(+)-ATPase and Ca+2-ATPase occurs as a result of non-covalent interaction of glucose with these enzymes.
与正常健康个体的红细胞相比，发现糖尿病患者（非胰岛素依赖型）的红细胞内源性生成的硫代巴比妥酸反应性丙二醛（MDA）水平高8至10倍，磷脂 - MDA加合物水平高13倍，Na(+)-K(+)-ATP酶活性降低15 - 20%，而Ca+2-ATP酶活性不变。将正常红细胞与浓度升高（15 - 35 mM）的葡萄糖（类似于糖尿病血浆中的葡萄糖浓度）一起孵育，导致脂质过氧化增加、磷脂 - MDA加合物形成、Na(+)-K(+)-ATP酶（25 - 50%）和Ca+2-ATP酶（50%）活性降低。2-脱氧葡萄糖在脂质过氧化和脂质加合物形成方面的效果是葡萄糖的80%。然而，其他糖类，如浓度为35 mM时测试的果糖、半乳糖、甘露糖、岩藻糖、葡糖胺、3-O-甲基甘露糖苷和蔗糖，导致脂质过氧化降低（20 - 30%）且未形成脂质 - MDA加合物。动力学研究表明，Na(+)-K(+)-ATP酶和Ca+2-ATP酶活性的降低先于脂质过氧化，因为红细胞与高浓度（15 - 35 mM）葡萄糖孵育30分钟内酶就发生失活，而脂质过氧化产物MDA在4小时出现，脂质 - MDA加合物在8小时出现。脂氧合酶途径抑制剂5,8,11-二十碳三烯酸和黄芩苷（5,6,7-三羟基黄酮）使葡萄糖诱导的脂质过氧化降低30%，MDA-脂质加合物形成降低26%。环氧化酶途径抑制剂吲哚美辛对红细胞中的脂质过氧化没有明显影响。然而，脂质过氧化抑制剂3-苯基吡唑啉酮、甲吡酮以及脂氧合酶途径抑制剂并未消除葡萄糖诱导的红细胞中Na(+)-K(+)-ATP酶和Ca+2-ATP酶活性的降低。红细胞产生15-羟基二十碳四烯酸（15-HETE），其会因葡萄糖而增加。这些结果表明脂氧合酶代谢产物的形成增强了葡萄糖诱导的脂质过氧化，并且Na(+)-K(+)-ATP酶和Ca+2-ATP酶的失活是葡萄糖与这些酶非共价相互作用的结果。
