Generation of hydrogen peroxide and failure of antioxidative responses in pancreatic islets of male C57BL/6 mice are associated with diabetes induced by multiple low doses of streptozotocin
Generation of hydrogen peroxide and failure of antioxidative responses in pancreatic islets of male C57BL/6 mice are associated with diabetes induced by multiple low doses of streptozotocin
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DOI：
10.1007/s00125-004-1367-x
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发表时间：
2004-04-01
期刊：
影响因子：
8.2
通讯作者：
Gleichmann, H
中科院分区：
文献类型：
--
作者：
Friesen, NTE;Büchau, AS;Gleichmann, H
目标/假设。我们研究了活性氧过氧化氢（H2O2）和抗氧化酶对多次低剂量链脲佐菌素（MLD-STZ）诱发的糖尿病发病机制的影响。方法。我们分离了 C57BL/6 小鼠的胰岛。对于离体分析，小鼠注射了 MLD-STZ。对于体外分析，将胰岛与不同浓度的 STZ、STZ 的两个部分（甲基亚硝基脲和 D-葡萄糖）、H2O2 或四氧嘧啶一起孵育。 H2O2 生成水平通过东莨菪碱法测定。我们通过半定量聚合酶链式反应评估了 Cu/Zn 和 Mn 超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶 (GPX) 的 mRNA 表达。 GPX 活性通过分光光度法测量。在体外，通过使用 ELISA 试剂盒测量免疫反应性胰岛素的基础和 D-葡萄糖刺激释放来测定 β 细胞功能。结果。离体后，MLD-STZ 显着增加雄性小鼠 H2O2 的产生，但对雌性小鼠没有影响。它还增加了雌性小鼠的 GPX 活性和过氧化氢酶、铜/锌和锰超氧化物歧化酶以及 GPX 的 mRNA 表达，但雄性小鼠则没有。在体外，STZ 仅显着刺激雄性小鼠胰岛中 H2O2 的产生。在雄性胰岛中，四氧嘧啶在高毒性浓度下会增加 H2O2 的产生，但 D-葡萄糖和甲基亚硝基脲则不会。 D-葡萄糖攻击后，STZ 和 H2O2 均剂量依赖性地抑制免疫反应性胰岛素的释放。结论/解释。结果表明，H2O2 参与了雄性 C57BL/6 小鼠 MLD-STZ 糖尿病的发病机制，且不会上调胰岛中的抗氧化酶。相反，雌性小鼠受到保护，可能是由于几种具有解毒 H2O2 潜力的酶的增加。
Aims/hypothesis. We studied the impact of the reactive oxygen species hydrogen peroxide (H2O2) and antioxidative enzymes on the pathogenesis of diabetes induced by multiple low doses of streptozotocin (MLD-STZ).Methods. We isolated the islets of C57BL/6 mice. For ex vivo analyses, mice had been injected with MLD-STZ. For in vitro analyses, islets were incubated with different concentrations of STZ, with either of the two moieties of STZ, methylnitrosourea and D-glucose, with H2O2 or with alloxan. Levels of H2O2 generation were measured by the scopoletin method. We assessed mRNA expression of Cu/Zn and Mn superoxide dismutase, catalase, and glutathione peroxidase (GPX) by semiquantitative polymerase chain reaction. GPX activity was measured spectrophotometrically. In vitro, beta cell function was assayed by measuring basal and D-glucose-stimulated release of immunoreactive insulin using an ELISA kit.Results. Ex vivo, MLD-STZ significantly increased H2O2 generation in male but not in female mice. It also increased GPX activity and mRNA expression of catalase, Cu/Zn and Mn superoxide dismutase, and GPX in female but not in male mice. In vitro, STZ significantly stimulated H2O2 generation in islets of male mice only. In male islets, alloxan increased H2O2 generation at a highly toxic concentration, but D-glucose and methylnitrosourea did not. Both STZ and H2O2 dose-dependently inhibited the release of immunoreactive insulin after a D-glucose challenge.Conclusions/interpretation. The results indicate that H2O2 participates in the pathogenesis of MLD-STZ diabetes in male C57BL/6 mice, which do not up-regulate antioxidative enzymes in islets. Conversely, female mice are protected, probably due to an increment of several enzymes with the potential to detoxify H2O2.