Jurkovicova D, Kopacek J, Stefanik P, Kubovcakova L, Zahradnikova A, Zahradnikova A, Pastorekova S, Krizanova O
Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlarska 5, 833 34, Bratislava, Slovakia.
Pflugers Arch. 2007 Jun;454(3):415-25. doi: 10.1007/s00424-007-0214-6. Epub 2007 Feb 7.
Hypoxic brain cell injury is a complex process that results from a series of intracellular events. In this work, we tested whether severe hypoxia for 6 h can affect gene expression and protein levels of intracellular calcium channels, ryanodine receptors, and inositol 1,4,5-trisphosphate receptors in mouse cerebellum. In addition, we tested the effect of hypoxia on cerebellar granular cells of rats. We have found that gene expression of types 1 and 2 IP(3) receptors is significantly increased after the exposure of mice to hypoxic stimulus for 6 h and also in rat cerebellar granular cells. Increased gene expression of IP(3) receptors was reflected in increased protein levels of these channels as well. In this process, reactive oxygen species are most probably involved, as antioxidant quercetin abolished hypoxia-induced increase in both types 1 and 2 IP3 receptor. Ryanodine receptors of types 1 and 2 and sarco(endo)plasmic reticulum Ca(2+)-ATPase were not affected by hypoxia on the level of messenger RNA. To test physiological consequences, we measured levels of intracellular calcium. We observed significantly elevated calcium level in hypoxic compared to normoxic cells. Deeper understanding of mechanisms, through which hypoxia regulates intracellular calcium, could point towards the development of new therapeutic approaches to reduce or suppress the pathological effects of cellular hypoxia, such as those seen in stroke or ischemia.
缺氧性脑细胞损伤是一个由一系列细胞内事件导致的复杂过程。在本研究中，我们测试了6小时的严重缺氧是否会影响小鼠小脑内细胞钙通道、兰尼碱受体和肌醇1,4,5-三磷酸受体的基因表达及蛋白质水平。此外，我们还测试了缺氧对大鼠小脑颗粒细胞的影响。我们发现，小鼠暴露于缺氧刺激6小时后以及在大鼠小脑颗粒细胞中，1型和2型肌醇三磷酸（IP₃）受体的基因表达均显著增加。IP₃受体基因表达的增加也反映在这些通道蛋白质水平的增加上。在这个过程中，活性氧很可能参与其中，因为抗氧化剂槲皮素消除了缺氧诱导的1型和2型IP₃受体的增加。1型和2型兰尼碱受体以及肌浆网Ca²⁺-ATP酶在信使核糖核酸水平上不受缺氧影响。为了测试生理后果，我们测量了细胞内钙水平。我们观察到，与正常氧合细胞相比，缺氧细胞中的钙水平显著升高。对缺氧调节细胞内钙的机制有更深入的了解，可能会为开发新的治疗方法指明方向，以减少或抑制细胞缺氧的病理影响，比如在中风或缺血中所见的影响。
