Aquaporin-4 expression related to hydrocephalus severity in hydrocephalus mice model

Background: Aquaporin-4 (AQP4), a water channel protein, is important in regulating brain water distribution. We hypothesized that increased expression of AQP4 in the kaolin-induced hydrocephalic mice brain is associated with the severity of hydrocephalus. This study aims to evaluate the AQP4 expression related to hydrocephalus severity in hydrocephalus mice model.Methods: Hydrocephalus was induced in 8-10 weeks Sprague-Dawley mice by kaolin injection into cisterna magna. The mice were randomly divided into normal control and hydrocephalus groups and were sacrificed on days 7, 14, and 21 after kaolin induction. The brains were analyzed for AQP4 expression by histological and immunohistochemistry analysis. Data were analyzed using SPSS version 25.0 for Windows.Results: Histopathological analysis showed an increase in AQP4 expression in periventricular zone astrocytes with the duration of hydrocephalus (p < 0.001). A significant difference in AQP4 expression in this study was found in the hydrocephalus group between the 7th and 14th days (p = 0.023), 7th and 21st days (p < 0.001), and 14th and 21st days (p = 0.044) after kaolin induction. The highest expression of AQP4 was found in the hydrocephalus induction group on day 21.Conclusion: The results showed that the expression of AQP4 increased with the severity of hydrocephalus. Expression of AQP4 in the kaolin-induced hydrocephalic mice brain was significantly altered depending on the length of time after kaolin induction. Changes in AQP4 expression in periventricular zone astrocytes may be a compensatory mechanism resulting in drainage of CSF accumulation.