Thrombin-induced oxidative stress contributes to the death of hippocampal neurons in vivo:: Role of microglial NADPH oxidase
Thrombin-induced oxidative stress contributes to the death of hippocampal neurons in vivo:: Role of microglial NADPH oxidase
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DOI：
10.1523/jneurosci.4306-04.2005
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发表时间：
2005-04-20
影响因子：
5.3
通讯作者：
Jin, BK
中科院分区：
文献类型：
--
作者：
Choi, SH;Lee, DY;Jin, BK
本研究调查了凝血酶，一种有效的小胶质细胞激活剂，是否可以通过激活小胶质细胞NADPH氧化酶诱导活性氧（ROS）的产生，以及这是否可能导致氧化损伤和随后的神经变性。海马内注射凝血酶后7天，尼氏染色和免疫组化使用神经元特异性核蛋白NeuN显示海马CA 1区神经元的显着损失。与此同时，在发生海马神经元变性的海马CA 1区，观察到了通过OX-42和OX-6免疫组织化学评估的凝血酶激活的小胶质细胞，以及通过氢乙啶组织化学评估的活性氧产生。凝血酶给药后不同时间点的逆转录-PCR显示诱导型一氧化氮合酶（iNOS）和几种促炎细胞因子的早期和瞬时表达。Western blot分析和免疫组化双标记显示小胶质细胞内iNOS的表达和定位增加。其他研究表明，凝血酶诱导膜（gp 91（phox））和胞质（p47（phox）和p67（phox））组分的上调，胞质蛋白（p47（phox）、p67（phox）和Rac 1）易位至膜，以及体内海马小胶质细胞中NADPH氧化酶的p67 phox表达，表明NADPH氧化酶的激活。凝血酶诱导的蛋白质氧化和海马CA 1区神经元的损失部分抑制NADPH氧化酶抑制剂和抗氧化剂。据我们所知，本研究是第一个证明，凝血酶诱导的神经毒性在体内海马是由小胶质细胞NADPH氧化酶介导的氧化应激。这表明凝血酶抑制或增强抗氧化剂可能有益于治疗与小胶质细胞源性氧化损伤相关的神经退行性疾病，如阿尔茨海默病。
The present study investigated whether thrombin, a potent microglial activator, can induce reactive oxygen species (ROS) generation through activation of microglial NADPH oxidase and if this may contribute to oxidative damage and consequent neurodegeneration. Seven days after intrahippocampal injection of thrombin, Nissl staining and immunohistochemistry using the neuronal-specific nuclear protein NeuN revealed a significant loss in hippocampal CA1 neurons. In parallel, thrombin-activated microglia, assessed by OX-42 and OX-6 immunohistochemistry, and ROS production, assessed by hydroethidine histochemistry, were observed in the hippocampal CA1 area in which degeneration of hippocampal neurons occurred. Reverse transcription-PCR at various time points after thrombin administration demonstrated an early and transient expression of inducible nitric oxide synthase ( iNOS) and several proinflammatory cytokines. Western blot analysis and double-label immunohistochemistry showed an increase in the expression of and the localization of iNOS within microglia. Additional studies demonstrated that thrombin induced the upregulation of membrane (gp91(phox)) and cytosolic (p47(phox) and p67(phox)) components, translocation of cytosolic proteins ( p47(phox), p67(phox), and Rac1) to the membrane, and p67phox expression of the NADPH oxidase in microglia in the hippocampus in vivo, indicating the activation of NADPH oxidase. The thrombin-induced oxidation of proteins and loss of hippocampal CA1 neurons were partially inhibited by an NADPH oxidase inhibitor and by an antioxidant. To our knowledge, the present study is the first to demonstrate that thrombin-induced neurotoxicity in the hippocampus in vivo is caused by microglial NADPH oxidase-mediated oxidative stress. This suggests that thrombin inhibition or enhancing antioxidants may be beneficial for the treatment of neurodegenerative diseases, such as Alzheimer's disease, that are associated with microglial-derived oxidative damage.