Downregulation of Potassium Chloride Cotransporter KCC2 After Transient Focal Cerebral Ischemia
Downregulation of Potassium Chloride Cotransporter KCC2 After Transient Focal Cerebral Ischemia
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DOI：
10.1161/strokeaha.109.570424
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发表时间：
2010-03-01
期刊：
影响因子：
8.3
通讯作者：
Frahm, Christiane
中科院分区：
文献类型：
--
作者：
Jaenisch, Nadine;Witte, Otto W.;Frahm, Christiane
背景和目的--氯化钾共转运体2(KCC2)是成人神经系统中主要的神经元氯化物挤出因子。因此，KCC2负责氯离子的内向电化学梯度，从而导致GABA介导的超极化反应。据报道，在某些病理生理条件下，由于KCC2的下调，GABA具有去极化作用。本研究首次分析了大鼠局灶性脑缺血后KCC2的表达。方法：采用大脑中动脉短暂阻断30分钟和120分钟分别造成轻度和重度脑缺血模型。采用定量聚合酶链式反应、Western blotting和免疫组织化学方法检测不同再灌注时间(2小时、1天、7天、30天、168天)缺血侧大脑半球KCC2基因和蛋白的表达。结果：重度缺血后KCC2基因表达水平显著降低，而轻度缺血后KCC2基因表达下调幅度更大。在梗死灶内可检测到表达KCC2的长期存活细胞。这些细胞被鉴定为GABA能中间神经元，主要表达细小蛋白。结论：我们的研究揭示了局灶性脑缺血后KCC2的神经元特异性下调。(笔划。2010年；41：e151-e159。)
Background and Purpose-The potassium chloride cotransporter 2 (KCC2) is the main neuronal chloride extruder in the adult nervous system. Therefore, KCC2 is responsible for an inwardly directed electrochemical gradient of chloride that leads to hyperpolarizing GABA-mediated responses. Under some pathophysiological conditions, GABA has been reported to be depolarizing because of a downregulation of KCC2. This is the first study to our knowledge analyzing the expression of KCC2 after a focal cerebral ischemia.Methods-Mild and severe ischemia were induced in rats by a transient occlusion of the middle cerebral artery for 30 and 120 minutes, respectively. KCC2 mRNA and protein expression were studied in the ischemic hemisphere after different reperfusion times (2 hour, 1 day, 7 days, 30 days, 168 days) by using quantitative polymerase chain reaction, Western blotting, and immunohistological staining.Results-We found a substantial decrease of KCC2 mRNA and protein levels in the ischemic hemisphere, with a stronger downregulation of KCC2 after severe vs mild ischemia. Long-term surviving cells expressing KCC2 could be detected in the infarct core. These cells were identified as GABAergic interneurons mainly expressing parvalbumin.Conclusions-Our study revealed a substantial neuron-specific downregulation of KCC2 after focal cerebral ischemia. (Stroke. 2010; 41: e151-e159.)