Aquaporin‐4 gene deletion in mice increases focal edema associated with staphylococcal brain abscess
Open Access
- 25 August 2005
- journal article
- Published by Wiley in Journal of Neurochemistry
- Vol. 95 (1), 254-262
- https://doi.org/10.1111/j.1471-4159.2005.03362.x
Abstract
Brain abscess is associated with local vasogenic edema, which leads to increased intracranial pressure and significant morbidity. Aquaporin-4 (AQP4) is a water channel expressed in astroglia at the blood–brain and brain–CSF barriers. To investigate the role of AQP4 in brain abscess-associated edema, live Staphylococcus aureus (105 colony-forming units) was injected into the striatum to create a focal abscess. Wild-type and AQP4-deficient mice had comparable immune responses as measured by brain abscess volume (∼ 3.7 mm3 at 3 days), bacterial count and cytokine levels in brain homogenates. Blood–brain barrier permeability was increased comparably in both groups as assessed by extravasation of Evans blue dye. However, at 3 days the AQP4 null mice had significantly higher intracranial pressure (mean ± SEM 27 ± 2 vs. 17 ± 2 mmHg; p < 0.001) and brain water content (81.0 ± 0.3 vs. 79.3 ± 0.5 % water by weight in the abscess-containing hemisphere; p < 0.01) than wild-type mice. Reactive astrogliosis was found throughout the abscess-containing hemisphere; however, only a subset of astrocytes in the peri-abscess region of wild-type mice had increased AQP4 immunoreactivity. Our findings demonstrate a protective effect of AQP4 on brain swelling in bacterial abscess, suggesting that AQP4 induction may reduce vasogenic edema associated with cerebral infection.Keywords
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