Shen Xi Qing, Miyajima Masakazu, Ogino Ikuko, Arai Hajime
Department of Neurosurgery and Research Institute for Diseases of Old Age, Juntendo University School of Medicine, Tokyo, Japan.
J Neurosurg. 2006 Dec;105(6 Suppl):459-64. doi: 10.3171/ped.2006.105.6.459.
Aquaporin (AQP) water channels play an important role in water movement in the central nervous system. The authors used an animal model to examine the relationship between AQP4 expression and spontaneously arrested hydrocephalus.
. Congenitally hydrocephalic H-Tx (hH-Tx) rats and nonhydrocephalic H-Tx (nH-Tx) rats were used in the study. Brain tissue sections were obtained from animals in both groups at 1 day, 1 week, 4 weeks, and 8 weeks of age. Sections were immunostained using AQP4 antibodies, and AQP4 expression was assessed. In the nH-Tx group, no AQP4 expression was seen in 1-day-old rats, and AQP4 expression was found in astrocytes around capillaries of the cerebral cortex and in ependymal cells lining the ventricles in 1-week-old rats. In the 4- and 8-week-old nH-Tx animals, AQP4 expression was seen in subpial zones of the cortex, on foot processes of pericapillary astrocytes, and in periventricular regions. A marked increase in cerebral cortical expression of AQP4 was observed at 8 weeks in the hH-Tx rats but not in the nH-Tx rats.
The authors hypothesize that the differences in cerebral AQP4 expression in the 1-day-old and 1-week-old nH-Tx rats compared with the 4- and 8-week-old nH-Tx rats may be related to the fact that the cerebrospinal fluid (CSF) circulation of newborns and infants differs from that of adults. It is also possible that the increased expression of AQP4 seen in the 8-week-old hH-Tx animals was related to the development of alternative pathways of CSF circulation, which also may occur in instances of spontaneously arrested hydrocephalus.
水通道蛋白(AQP)水通道在中枢神经系统的水转运中起重要作用。作者使用动物模型来研究AQP4表达与自发性静止性脑积水之间的关系。
本研究使用先天性脑积水的H-Tx(hH-Tx)大鼠和非脑积水的H-Tx(nH-Tx)大鼠。在1日龄、1周龄、4周龄和8周龄时从两组动物获取脑组织切片。切片用AQP4抗体进行免疫染色,并评估AQP4表达。在nH-Tx组中,1日龄大鼠未见AQP4表达,1周龄大鼠在大脑皮质毛细血管周围的星形胶质细胞和脑室衬里的室管膜细胞中发现AQP4表达。在4周龄和8周龄的nH-Tx动物中,在皮质的软膜下区域、毛细血管周围星形胶质细胞的足突以及脑室周围区域可见AQP4表达。在hH-Tx大鼠中,8周龄时观察到大脑皮质AQP4表达明显增加,而nH-Tx大鼠未出现这种情况。
作者推测,与4周龄和8周龄的nH-Tx大鼠相比,1日龄和1周龄的nH-Tx大鼠大脑AQP4表达的差异可能与新生儿和婴儿的脑脊液(CSF)循环不同于成年人这一事实有关。8周龄的hH-Tx动物中AQP4表达增加也可能与CSF循环替代途径的发展有关,这在自发性静止性脑积水病例中也可能发生。