Expression of the water-channel protein aquaporin 4 in the H-Tx rat: possible compensatory role in spontaneously arrested hydrocephalus

Abstract

Object 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. Methods 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 w...