Department of Neurology, University of Heidelberg, Heidelberg, Germany.
Neuroscience. 2012 Apr 19;208:109-22. doi: 10.1016/j.neuroscience.2012.01.048. Epub 2012 Feb 10.
Hypothermia is one of the most robust experimental neuroprotective interventions against cerebral ischemia. Identification of molecular pathways and gene networks together with single genes or gene families that are significantly associated with neuroprotection might help unravel the mechanisms of therapeutic hypothermia.
We performed a microarray analysis of ischemic rat brains that underwent 90 min of middle cerebral artery occlusion (MCAO) and 48 h of reperfusion. Hypothermia was induced for 4 h, starting 1 h after MCAO in male Wistar rats. At 48 h, magnetic resonance imaging (MRI) was performed for infarct volumetry, and functional outcome was determined by a neuroscore. The brain gene expression profile of sham (S), ischemia (I), and ischemia plus hypothermia (HI) treatment were compared by analyzing changes of individual genes, pathways, and networks. Real-time reverse-transcribed polymerase chain reaction (RT-PCR) was performed on selected genes to validate the data.
Rats treated with HI had significantly reduced infarct volumes and improved neuroscores at 48 h compared with I. Of 4067 genes present on the array chip, HI compared with I upregulated 50 (1.23%) genes and downregulated 103 (3.20%) genes equal or greater than twofold. New genes potentially mediating neuroprotection by hypothermia were HNRNPAB, HIG-1, and JAK3. On the pathway level, HI globally suppressed the ischemia-driven gene response. Twelve gene networks were identified to be significantly altered by HI compared with I. The most significantly altered network contained genes participating in apoptosis suppression.
Our data suggest that although hypothermia at the pathway level restored gene expression to sham levels, it selectively regulated the expression of several genes implicated in protein synthesis and folding, calcium homeostasis, cellular and synaptic integrity, inflammation, cell death, and apoptosis.
低温是针对脑缺血最有效的实验性神经保护干预措施之一。鉴定与神经保护显著相关的分子途径和基因网络以及单个基因或基因家族，可能有助于揭示治疗性低温的机制。
我们对经历 90 分钟大脑中动脉闭塞（MCAO）和 48 小时再灌注的缺血大鼠脑进行了微阵列分析。雄性 Wistar 大鼠在 MCAO 后 1 小时开始进行 4 小时的低温诱导。在 48 小时时，进行磁共振成像（MRI）以进行梗死体积测量，并通过神经评分确定功能结果。通过分析单个基因、途径和网络的变化，比较了假手术（S）、缺血（I）和缺血加低温（HI）治疗的脑基因表达谱。对选定的基因进行实时逆转录聚合酶链反应（RT-PCR）以验证数据。
与 I 相比，HI 治疗的大鼠在 48 小时时梗死体积明显减小，神经评分提高。在芯片上存在的 4067 个基因中，HI 与 I 相比上调了 50 个（1.23%）基因，并下调了 103 个（3.20%）基因，倍数等于或大于 2 倍。新的基因可能通过低温介导神经保护，如 HNRNPAB、HIG-1 和 JAK3。在途径水平上，HI 全局抑制了由缺血引起的基因反应。与 I 相比，鉴定出 12 个基因网络发生了显著改变。改变最显著的网络包含参与凋亡抑制的基因。
我们的数据表明，尽管低温在途径水平上使基因表达恢复到假手术水平，但它选择性地调节了几个参与蛋白质合成和折叠、钙稳态、细胞和突触完整性、炎症、细胞死亡和凋亡的基因的表达。
