The effect of hypothermia on gene expression in the ischemic hippocampal CAI

众所周知，亚低温可以防止神经元因缺血而损伤，但其机制尚未确定。在本研究中，我们组装了一个基于遥测仪的脑温度控制系统，可以连续监测和调节脑温度，以研究低温的神经保护作用。将脑温度变送器置于沙鼠颅骨上，诱导其短暂缺血5min。再循环后1小时开始降低脑温，在32℃下保持24小时。结果表明，该系统持续调节沙鼠脑温度，证明缺血后低温对海马CA1具有有效且持久的神经保护作用。然后，我们试图检测沙鼠海马CA1基因表达在缺血和/或低温下的变化。除了干扰素诱导基因2、GTPase、Ca<^2+>泵等多种缺血诱导基因产物外，低温还可诱导酪氨酸磷酸酶受体类型等多种基因特异性上调或下调。这一结果表明，低温诱导的这些基因可能为脑中风预防/治疗的发展提供一种新的策略。

It has been known that mild hypothermia prevents neuronal damage against ischemia, however, the mechanism has not been established. In the present study, we assembled a telemeter-based brain temperature control system that allows continuous monitoring and regulating of brain temperature to investigate the neuroprotective effects of hypothermia. A brain temperature transmitter was attached to the gerbil skull and 5-min transient ischemia was induced. The brain temperature was lowered from 1 hour after recirculation and kept at 32℃ for 24 hours. The result showed that this system regulated gerbil brain temperature continuously, and proved that the post-ischemic hypothermia provided effective and long lasting neuroprotection in the hippocampal CA1. Then, we attempted to examine changes of gene expression in gerbil hippocampal CA1 subjected to ischemia and/or hypothermia. Besides numerous ischemia induced gene products such as interferon induced gene 2, GTPase, and Ca<^2+> pump, hypothermia induced specific up regulation or down regulation of several genes including tyrosine phosphatase-receptor type. This result suggests that these genes induced by hypothermia may be used to present a novel strategy for development of preventives/therapeutics of brain stroke.