Kaindl Angela M, Sifringer Marco, Koppelstaetter Andrea, Genz Kerstin, Loeber Rebecca, Boerner Constanze, Stuwe Janine, Klose Joachim, Felderhoff-Mueser Ursula
Department of Pediatric Neurology, Charité-Universitätsmedizin Berlin, Campus Virchow-Klinikum, Berlin, Germany.
Ann Neurol. 2008 Nov;64(5):523-34. doi: 10.1002/ana.21471.
Oxygen toxicity has been identified as a risk factor for adverse neurological outcome in survivors of preterm birth. In infant rodent brains, hyperoxia induces disseminated apoptotic neurodegeneration. Because a tissue-protective effect has been observed for recombinant erythropoietin (rEpo), widely used in neonatal medicine for its hematopoietic effect, we examined the effect of rEpo on hyperoxia-induced brain damage.
Six-day-old C57Bl/6 mice or Wistar rats were exposed to hyperoxia (80% O(2)) or normoxia for 24 hours and received rEpo or normal saline injections intraperitoneally. The amount of degenerating cells in their brains was determined by DeOlmos cupric silver staining. Changes of their brain proteome were determined through two-dimensional electrophoresis and mass spectrometry. Western blot, enzyme activity assays and real-time polymerase chain reaction were performed for further analysis of candidate proteins.
Systemic treatment with 20,000 IE/kg rEpo significantly reduced hyperoxia-induced apoptosis and caspase-2, -3, and -8 activity in the brains of infant rodents. In parallel, rEpo inhibited most brain proteome changes observed in infant mice when hyperoxia was applied exclusively. Furthermore, brain proteome changes after a single systemic rEpo treatment point toward a number of mechanisms through which rEpo may generate its protective effect against oxygen toxicity. These include reduction of oxidative stress and restoration of hyperoxia-induced increased levels of proapoptotic factors, as well as decreased levels of neurotrophins.
These findings are highly relevant from a clinical perspective because oxygen administration to neonates is often inevitable, and rEpo may serve as an adjunctive neuroprotective therapy.
氧中毒已被确认为早产幸存者不良神经结局的一个风险因素。在新生啮齿动物脑中，高氧会诱发弥漫性凋亡性神经变性。由于重组促红细胞生成素（rEpo）因其造血作用而在新生儿医学中广泛应用，且已观察到其具有组织保护作用，我们研究了rEpo对高氧诱导的脑损伤的影响。
将6日龄的C57Bl/6小鼠或Wistar大鼠暴露于高氧（80% O₂）或常氧环境24小时，并腹腔注射rEpo或生理盐水。通过DeOlmos铜银染色确定其脑中变性细胞的数量。通过二维电泳和质谱法测定其脑蛋白质组的变化。进行蛋白质印迹、酶活性测定和实时聚合酶链反应以进一步分析候选蛋白质。
以20,000 IE/kg的rEpo进行全身治疗可显著减少新生啮齿动物脑中高氧诱导的细胞凋亡以及半胱天冬酶-2、-3和-8的活性。同时，当仅施加高氧时，rEpo抑制了新生小鼠中观察到的大多数脑蛋白质组变化。此外，单次全身rEpo治疗后脑蛋白质组的变化指向rEpo可能产生其对氧中毒保护作用的多种机制。这些机制包括氧化应激的降低以及高氧诱导的促凋亡因子水平升高和神经营养因子水平降低的恢复。
从临床角度来看，这些发现具有高度相关性，因为给新生儿输氧往往不可避免，而rEpo可能作为一种辅助性神经保护疗法。
