大鼠全脑照射后早期大脑皮质水通道蛋白4表达变化的研究

目的观察单次全脑照射大鼠大脑皮质水通道蛋白4(AQP4)表达的变化,探讨AQP4在早期放射性脑损伤中的作用。方法将雄性SD大鼠100只随机分为2、10、30 Gy单次全脑照射后1d、1周和1个月及对照10个组别,构建放射性脑损伤大鼠脑组织芯片,用免疫组化法检测皮质AQP4蛋白表达变化。结果与对照组比较,2 Gy照射后各时间点皮质AQP4表达水平无明显变化;10、30 Gy照射后1 d皮质AQP4表达迅速降低,照后1周达最低点(P<0.01),1个月时表达水平又明显高于对照组(P<0.05);随着受照剂量增加AQP4表达也明显降低,30 Gy组达最低点(P<0.01)。结论大鼠全脑照射后脑皮质AQP4表达呈时程性和剂量依赖性变化;早期放射性脑损伤中AQP4表达下降是一种保护性反应,具有减轻脑水肿效应。

Early changes of aquaporin-4 in the cortex of rats following whole brain irradiation

Objective To investigate the early changes of aquaporin-4 (AQP4) expression in the cortex of rats following whole brain irradiation and its role in the early phase irradiation-induced brain injury. Methods 100 male Sprague-Dawley rats were randomly divided into sham-irradiation group,and irradiation group.One day,1 week and 1 month after whole brain irradiation of these rats with a single-dose of 2,10 and 30 Gy by 4 MeV electron beam.Tissue microarray of radiation-induced brain injury in rats was construc- ted and AQP4 expression in the cortex was examined by immunohisto-ehemical method.Results Com- pared with the sham-irradiation group,AQP4 expression in the cortex of rats in the 2 Gy group showed no ob- vious change.However,AQP4 expression in 10 Gy and 30 Gy groups decreased quickly in D1 post-radiation and reached the lowest point one week post-radiation.Then,it increased slowly and the level of AQP4 ex- pression in M1 was obviously higher than those of the sham-irradiation group (P<0.05).AQP4 expression lowered in a manner of dose-dependent after whole brain irradiation and reached the lowest point at 30 Gy. Conclusions Aquaporin-4 expression in the rat cortex changed at in a time-and-dose-dependent manner af- ter whole brain irradiation.After irradiation,the lowered AQP4 expression is a protective response to blood- brain barrier,as it could reduce cerebral edema.