大鼠伽玛刀照射后AQP4的表达及其与脑水肿的相关性研究

AQP4 expression and its relationship with brain edema after gamma kife radiosurgery in rats

目的探讨大鼠伽玛刀照射后AQP4的表达及其与脑水肿的相关性。方法Wistar大鼠随机分成对照组和实验组。实验组通过伽玛刀照射尾状核头部（100Gy，4mm）制成大鼠脑水肿模型。观察时间点选定于照射后1、3、7、15、30和45d。干湿比重法检测脑含水量，免疫组化、原位杂交检测AQP4及其mRNA的表达。结果AQP4及其mRNA在软脑膜下星形胶质细胞、脉络膜丛、室管膜及血管周围星形胶质细胞胞膜上均有表达。照射后，上述部位AQP4及其mRNA表达显著增强，30d达高峰。AQP4 mRNA及AQP4，AQP4与脑含水量的变化呈显著正相关。结论伽玛刀照射大鼠尾状核后，可促使特定区域内AQP4及其mRNA表达增加，其意义之一可能在于参与脑水肿的发生发展。

Objective To explore AQP4 expression and its relationship with brain edema after gamma knife radiosurgery （GKRS） in rats. Methods Wistar rats were divided into two groups-the control group and experimental group. The experimental group model was established by radiating rat left rotral caudate nucleus with GKRS （100 Gy, 4 mm）, and was examinded at interval times of 1 d, 3 d, 7 d, 15 d, 30 d and 45 d. Brain water content （BWC） was determined by wet-dry weighing method. AQP4 expression on mRNA and protein were measured by immunohistochemistry （ICH） and in situ hybridization （ISH）. Results In control group, AQP4 protein and its mRNA were expressed in subpial astrocytes, choroid plexus, ependyma and perivascular astrocytes. After GKRS, AQP4 protein and its mRNA in these sites were enhanced, and became most remarkable at 30 d. The positive corrlationship was showed between AQP4 and its mRNA, and AQP4 and BWC. Conclusions AQP4 protein and its mRNA can be induced in some brain zone after irradiating rat left rotral caudate nucleus with GKRS. The increased expression of AQP4 and its mRNA may play a role in the ocurrence or development of brain edema after GKRS.