Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, ICBS, UFRGS, Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre, RS, 90035-003, Brazil.
Laboratório de Neuroproteção e Doenças Neurometabólicas, Departamento de Bioquímica, ICBS, UFRGS, Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre, RS, 90035-003, Brazil.
Mol Neurobiol. 2018 May;55(5):4098-4106. doi: 10.1007/s12035-017-0634-z. Epub 2017 Jun 7.
Hypoxanthine is the major purine involved in the salvage pathway of purines in the brain. High levels of hypoxanthine are characteristic of Lesch-Nyhan Disease. Since hypoxanthine is a purine closely related to ATP formation, the aim of this study was to investigate the effect of intrastriatal hypoxanthine administration on neuroenergetic parameters (pyruvate kinase, succinate dehydrogenase, complex II, cytochrome c oxidase, and ATP levels) and mitochondrial function (mitochondrial mass and membrane potential) in striatum of rats. We also evaluated the effect of cell death parameters (necrosis and apoptosis). Wistar rats of 60 days of life underwent stereotactic surgery and were divided into two groups: control (infusion of saline 0.9%) and hypoxanthine (10 μM). Intrastriatal hypoxanthine administration did not alter pyruvate kinase activity, but increased succinate dehydrogenase and complex II activities and diminished cytochrome c oxidase activity and immunocontent. Hypoxanthine injection decreased the percentage of cells with mitochondrial membrane label and increased mitochondrial membrane potential labeling. There was a decrease in the number of live cells and an increase in the number of apoptotic cells by caused hypoxanthine. Our findings show that intrastriatal hypoxanthine administration altered neuroenergetic parameters, and caused mitochondrial dysfunction and cell death by apoptosis, suggesting that these processes may be associated, at least in part, with neurological symptoms found in patients with Lesch-Nyhan Disease.
次黄嘌呤是大脑中嘌呤补救途径中主要涉及的嘌呤。高浓度的次黄嘌呤是莱施-尼汉病的特征。由于次黄嘌呤是一种与 ATP 形成密切相关的嘌呤，因此本研究旨在研究纹状体中脑内次黄嘌呤给药对神经能量参数（丙酮酸激酶、琥珀酸脱氢酶、复合物 II、细胞色素 c 氧化酶和 ATP 水平）和线粒体功能（线粒体质量和膜电位）的影响。我们还评估了细胞死亡参数（坏死和凋亡）的影响。60 天大的 Wistar 大鼠接受立体定向手术，并分为两组：对照组（输注生理盐水 0.9%）和次黄嘌呤组（10 μM）。纹状体内次黄嘌呤给药不会改变丙酮酸激酶活性，但会增加琥珀酸脱氢酶和复合物 II 活性，降低细胞色素 c 氧化酶活性和免疫含量。次黄嘌呤注射减少了具有线粒体膜标记的细胞百分比，并增加了线粒体膜电位标记。次黄嘌呤导致活细胞数量减少和凋亡细胞数量增加。我们的研究结果表明，纹状体内次黄嘌呤给药改变了神经能量参数，并通过凋亡引起线粒体功能障碍和细胞死亡，表明这些过程至少部分与莱施-尼汉病患者的神经症状有关。
