Expression of Aquaporin 4 in Diffuse Brain Injury of Rats / 法医学杂志

OBJECTIVE@#To observe the expression of aquaporin 4 (AQP4) in diffuse brain injury (DBI) of rats and to explore the corresponding effect of AQP4 for brain edema.@*METHODS@#The rat model of DBI was established using Marmarou's impact-compression trauma model. Brain water content was measured by dry-wet weight method. Blood-brain barrier permeability was evaluated by Evans blue (EB) staining. Immunohistochemical method was used to observe the expression of AQP4.@*RESULTS@#Brain water content increased after 3 h and peaked at 24 h after DBI. Brain EB content significantly increased and peaked at 12 h after DBI. The expression of AQP4 significantly increased after 3 h and peaked at 24 h after DBI, and the number of AQP4 positive astrocytes increased.@*CONCLUSION@#The increment of the permeability of blood-brain barrier and the expression of AQP4 may contribute to the development of brain edema in rat DBI. The change of AQP4 expression in astrocytes may also contribute to determine DBI.

Enhanced expression of aquaporin-9 in rat brain edema induced by bacterial lipopolysaccharides / 华中科技大学学报（医学）（英德文版）

To investigate the role of AQP9 in brain edema, the expression of AQP9 in an infectious rat brain edema model induced by the injection of lipopolysaccharide (LPS) was examined. Immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) analysis demonstrated that the expressions of AQP9 mRNA and protein at all observed intervals were significantly increased in LPS-treated animals in comparison with the control animals. Time-course analysis showed that the first signs of blood-brain barrier disruption and the increase of brain water content in LPS-treated animals were evident 6 h after LPS injection, with maximum value appearing at 12 h, which coincided with the expression profiles of AQP9 mRNA and protein in LPS-treated animals. The further correlation analysis revealed strong positive correlations among the brain water content, the disruption of the blood-brain barrier and the enhanced expressions of AQP9 mRNA and protein in LPS-treated animals. These results suggested that the regulation of AQP9 expression may play important roles in water movement and in brain metabolic homeostasis associated with the pathophysiology of brain edema induced by LPS injection.

Calcificaciones cerebrales con edema perilesional. ¿otro estadio de la neurocisticercosis? reporte de un caso / Brain calcification with perilesional edema ¿another stage of neurocysticercosis report of one case

Las calcificaciones cerebrales ocurren en estadíos tardíos de varias enfermedades infecciosas o inflamatorias incluyendo la neurocisticercosis (NCC). Existen escasos reportes en la literatura médica internacional sobre la aparición de edema alrededor de calcificaciones acompañado de síntomas neurológicos. Se presenta caso de una paciente evaluada de emergencia en dos oportunidades por presentar crisis epilépticas y déficit neurológico. La paciente había recibido albendazol hacía 10 años para tratamiento de cisticercos y era portadora de válvula para manejo de hidrocefalia. La tomografía cerebral mostró calcificaciones cerebrales con edema perilesional en ambas ocasiones, el cual mejoró después del tratamiento con esteroides. Se discuten las teorías sobre este fenómeno. Este caso apoya el concepto de que la calcificación con edema perilesionales otro estadío poco reconocido de la NCC...

Brain edema in acute liver failure.

Brain edema and consequent increase in intracranial pressure is a major complication of acute liver failure (ALF) and is a major cause of death in this condition. Rapid accumulation of ammonia in brain has been implicated in the pathogenesis of brain edema in ALF. Increased brain ammonia may cause brain swelling via the osmotic effects of an increase in astrocytic glutamine concentration or by inhibition of glutamate removal from brain extracellular space. Acute liver failure results in altered expression of several genes in the brain, some of which code for proteins involved in central nervous system function such as the glutamate transporter GLT-1, the astrocytic structural protein, glial fibrillary acidic protein, and the water channel protein, aquaporin IV. Loss of expression of GLT-1 results in increased extracellular brain glutamate. Therapeutic measures currently used to prevent and treat brain edema in acute liver failure include mannitol; strategies aimed at lowering of gut ammonia production are generally ineffective. Studies in experimental animals suggest that mild hypothermia or the use of L-ornithine-L-aspartate may be useful in the prevention of brain edema in these patients.