Expression of Aquaporins-4 and Its Relation to Brain Water Content in the Developmental Mouse Brain
|School||Nanjing Medical University|
|Keywords||Aquaporin 4 Brain water content Development Knockout Water balance Connexin 43 Ependymal cells Gap junctions|
Studies have shown that aquaporin-4 (AQP4) involved in the formation and maintenance of brain water balance. However, AQP4 expression changes throughout the brain regions, its correlation and brain water content changes during development has not been reported. Western blot analysis and optical density analysis CD1 mice in the first week after birth, the brain of AQP4 expression level of only 21.3% of the adult level, but in two weeks AQP4 expression was significantly increased to 67.4% of the adult level, to 4 weeks reached 88.6% of the adult level. Consistent with AQP4 expression increased brain water content dynamically reduced during development. The statistical analysis of AQP4 protein expression levels and brain water content was confirmed during the development of some of the negative correlation relationship (rP2P, = 0.92, P = 0.002). AQP4 knock-out in addition to mice and wild-type mice brain water content in the first weeks after birth there was no significant sex difference. However, from the the second Zhou Zhicheng year, AQP4 knockout mice basis of brain water content higher than the control group of the same litter. In addition, our application of immunohistochemistry combined with semi-quantitative image analysis to study changes in the temporal and spatial expression of AQP4 CD1 mice brain after birth. The results show that AQP4 expression in the brain stem and hypothalamus than earlier in the cerebral cortex and cerebellum. To 14 days after birth, the brain regions perivascular astrocytes protrusions and chamber tube membrane cell basolateral membrane expression of AQP4 showed a mature characterized. These results reveal the characteristics of the development of the brain AQP4, AQP4 play an important role in brain water balance homeostasis mature establish direct evidence. The ependymal cells arranged along the brain wall epithelial cells, participation constitutes the brain - brain barrier and cerebrospinal fluid formation. Studies have shown that ependymal cells basolateral membrane water has a rapid transit role of aquaporin-4 (AQP4) expression. AQP4-specific expression characteristics suggesting that it may participate in to maintain the integrity of the ependymal membrane structure and function. This thesis the application of the laboratory building adult the AQP4 gene knock deratization as the object of study, to verify speculated. Histological analysis showed that AQP4 knockout mouse lateral ventricle and aqueduct ependymal layer structure disorders. 92.7% of AQP4 knockout mice exhibit reduced lateral ventricle volume, 7.3% Display expanded or normal lateral ventricles, accompanied by narrow aqueduct. Immunohistochemical results showed that AQP4 deletion leads to reduce the gap junction protein 43 (Cx43) expression in the ependymal cells. Electron microscopy results further confirmed AQP4 knock in addition to the mouse ependymal membrane cell basolateral membrane junctional complex missing. In addition, compared with wild-type mice, AQP4 knock addition to decreased production of rat cerebrospinal fluid and brain water content increased. These results suggest that AQP4 play an important role in maintaining the structure and function of ependymal. In addition, AQP4 knock ventricle phenotype in addition lead to abnormal individual differences suggest that AQP4 function polymorphism.