PURPOSE To investigate the effects and mechanisms of NADPH on Kainic acid (KA)-induced excitotoxicity. METHODS KA, a non-N-methyl-d-aspartate glutamate receptor agonist, was exposed to adult SD rats via intrastriatal injection and rat primary cortical neurons to establish excitotoxic models in vivo and in vitro, respectively. To determine the effects of NADPH on KA-induced excitotoxicity, neuronal survival, neurologically behavioral score and oxidative stress were evaluated. To explore the mechanisms of neuroprotective effects of NADPH, the autophagy-lysosome pathway related proteins were detected. RESULTS In vivo, NADPH (1 mg/kg or 2 mg/kg) diminished KA (2.5 nmol)-induced enlargement of lesion size in striatum, improved KA-induced dyskinesia and reversed KA-induced activation of glial cells. Nevertheless, the neuroprotective effect of NADPH was not significant under the condition of autophagy activation. NADPH (2 mg/kg) inhibited KA (2.5 nmol)-induced down-regulation of TP-53 induced glycolysis and apoptosis regulator (TIGAR) and p62, and up-regulation of the protein levels of LC3-II/LC3-I, Beclin-1 and Atg5. In vitro, the excitotoxic neuronal injury was induced after KA (50 μM, 100 μM or 200 μM) treatment as demonstrated by decreased cell viability. Moreover, KA (100 μM) increased the intracellular levels of calcium and reactive oxygen species (ROS) and declined the levels of the reduced form of glutathione (GSH). Pretreatment of NADPH (10 μM) effectively reversed these changes. Meanwhile NADPH (10 μM) inhibited KA (100 μM)-induced down-regulation of TIGAR and p62, and up-regulation of the ratio of LC3-II/LC3-I, Beclin-1, Atg5, active-cathepsin B and active-cathepsin D. CONCLUSIONS Our data provide a possible mechanism that NADPH ameliorates KA-induced excitotoxicity by blocking the autophagy-lysosome pathway and up-regulating TIGAR along with its antioxidant properties.

中文翻译：

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NADPH可通过大鼠纹状体和原代皮层神经元中的自噬溶酶体途径来防止海藻酸诱导的兴奋性毒性。

目的探讨NADPH对海藻酸（KA）诱导的兴奋性毒性的作用及其机制。方法将非N-甲基-d-天冬氨酸谷氨酸受体激动剂KA通过纹状体内注射和大鼠原代皮层神经元暴露于成年SD大鼠体内，并在体内和体外建立兴奋性毒性模型。为了确定NADPH对KA诱导的兴奋性毒性的作用，评估了神经元存活，神经行为评分和氧化应激。为了探索NADPH的神经保护作用的机制，检测了自噬-溶酶体途径相关的蛋白质。结果在体内，NADPH（1 mg / kg或2 mg / kg）减少了KA（2.5 nmol）诱导的纹状体病变面积增大，改善了KA诱导的运动障碍并逆转了KA诱导的神经胶质细胞活化。不过，自噬激活条件下NADPH的神经保护作用不明显。NADPH（2 mg / kg）抑制KA（2.5 nmol）诱导的TP-53诱导的糖酵解和凋亡调节剂（TIGAR）和p62的下调，以及LC3-II / LC3-I的蛋白质水平的上调， Beclin-1和Atg5。在体外，KA（50μM，100μM或200μM）处理后诱发了兴奋性毒性神经元损伤，如细胞活力降低所证明。此外，KA（100μM）增加了细胞内钙和活性氧（ROS）的水平，并降低了还原型谷胱甘肽（GSH）的水平。NADPH（10μM）的预处理有效地逆转了这些变化。同时，NADPH（10μM）抑制KA（100μM）诱导的TIGAR和p62下调，以及LC3-II / LC3-I，Beclin-1，Atg5，