The receptors for the complement anaphylatoxins C3a and C5a are expressed by glial cells and neurons in normal and inflamed brain. Previous studies demonstrated modest elevations in mRNA expression of these receptors in a model of focal cerebral ischemia. Using a similar model system for both mice and rats, we report markedly different patterns of anaphylatoxin receptor mRNA expression in cerebral ischemia. C5a receptor expression was dramatically elevated within 3 h after middle cerebral artery occlusion, while C3aR expression was reduced to 25% of control animals. By 24 h post-occlusion, expression of both receptors was higher than at any other time point examined. This increased expression at late time points after occlusion is most likely the result of massive infiltration of leukocytes expressing the receptors. We also observed increased receptor mRNA expression in sham-operated animals, indicating that the procedures used for arterial occlusion affects mechanisms regulating receptor expression. This latter result highlights the importance of including this important control group in ischemic model systems for proper interpretation of changes in gene expression.

中文翻译：

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永久性局灶性局部缺血后补体C3a和C5a受体的表达：另一种解释。

正常和发炎的大脑中的神经胶质细胞和神经元表达补体过敏毒素C3a和C5a的受体。先前的研究表明在局灶性脑缺血模型中这些受体的mRNA表达适度升高。使用针对小鼠和大鼠的相似模型系统，我们报告了脑缺血中过敏毒素受体mRNA表达的明显不同模式。C5a受体表达在大脑中动脉闭塞后3小时内显着升高，而C3aR表达降低至对照组动物的25％。闭塞后24小时，两种受体的表达均高于检查的任何其他时间点。在闭塞后的较晚时间点上这种增加的表达很可能是表达受体的白细胞大量浸润的结果。我们还观察到假手术动物中受体mRNA表达的增加，表明用于动脉闭塞的程序会影响调节受体表达的机制。后一个结果突显了在缺血模型系统中包括这个重要对照组的重要性，以正确解释基因表达的变化。