Expression of Aquaporin 1 and 4 in the Choroid Plexus and Brain Parenchyma of Kaolin-Induced Hydrocephalic Rats

다국어 초록 (Multilingual Abstract)

Objective: Aquaporin (AQP) is a recently discovered protein that regulates water homeostasis. The present study examines changes in AQP 1 and 4 in kaolin induced experimental hydrocephalic rats to elucidate the pathophysiology of waterhomeostasis in the disease.
Methods: Hydrocephalus was induced by percutaneous intracisternal injection of kaolin. The brain parenchyma and choroid plexus were obtained at 3, 7, 14 and 30 days after injection. Protein expressions of AQP 1 and 4 were measured bywestern blot, immunohistochemistry (IHC) and immunofluorescence (IF) stains.
Results: In the choroid plexus of the kaolin-induced hydrocephalus group, AQP 1 expression identifed by western blotexhibited sharp decrease in the early stage (55% by the 3rd day and 22% by the 7th day), but indicated a 2.2-fold increasein the later stage (30th day) in comparison with control groups. In the parenchyma, a quantitative measurement of AQP 4expression revealed variable results on the 3rd and 7th days, but indicated expression 2.1 times higher than the control inthe later stage (30th day). In addition, the IHC and IF fndings supported the patterns of expression of AQP 1 in the choroidplexus and AQP 4 in the parenchyma.
Conclusion: Expression of AQP 1 decreased sharply in the choroid plexus of acute hydrocephalus rats and increased atlater stages. Expression of AQP 4 in the brain parenchyma was variable in the early stage in the hydrocephalus group, butwas higher than in the control in the later stage. These fndings suggest a compensating role of AQPs in water physiologyin hydrocephalus.