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This study aimed at obtaining an in-depth mapping of expressional changes of the cerebral microvasculature after transient global cerebral ischemia (GCI) and the impact on these GCI-induced expressional changes of post-GCI treatment with a mitogen-activated protein kinase kinase (MEK1/2) inhibitor. GCI was induced in male Wistar rats followed by treatment with either vehicle or the MEK1/2 inhibitor U0126 every 12 h post-GCI. Seventy-two hours after GCI or sham surgery, the cerebral microvasculature was isolated and the protein content analysed with state-of-the-art mass spectrometry. The proteomic profile of the isolated cerebral microvasculature 72 h after GCI (compared to sham) indicated that the main expressional changes could be divided into nine categories: (1) cellular respiration, (2) remodelling of the extracellular matrix, (3) decreased contractile phenotype, (4) clathrin-mediated endocytosis, (5) ribosomal activity, (6) expression of chromatin structure-related proteins, (7) altered synaptic activity, (8) altered G-protein signalling and (9) instability of the membrane potential. Treatment with U0126 partly normalized the expression of one or more of the proteins in all nine categories. Flow cytometry confirmed key findings from the proteome such as upregulation of the extracellular proteins lamininβ2 and nidogen2 ( p < 0.05) after GCI. These results provide valuable molecular insight into the broad and complex expressional changes in the cerebral microvasculature after GCI and the effect of early MEK1/2 inhibitor treatment on these changes. [ABSTRACT FROM AUTHOR]

Mouse models of global cerebral ischemia (GCI) allow experimental examination of cerebral pathophysiology in genetically modified mice and fast screening of new treatment strategies. Various surgical protocols of GCI-induction in mice have been published; however, many of these studies are hindered by limited neurological assessment protocols and present insufficient reporting of the cumulative survival rate. Therefore, we aim at developing a reproducible and easily implementable model of transient GCI in mice with minimal impact on normal mouse behavior. GCI was induced in male C57BL/6 mice by bilateral occlusion of the common carotid arteries for 10 min combined with isoflurane-induced hypotension which resulted in severe reduction in the cerebral blood flow of the forebrain. Sham operation served as a control. Exploratory behavior was evaluated in a home-cage environment the day before and again daily for up to 7 days after GCI or sham operation and was found to be significantly decreased 1-7 days after GCI compared to sham. Furthermore, we found delayed neuronal cell death in the frontal cortex and hippocampus 5 and 7 days after GCI but not at day 3 or after sham operation. The survival rate at day 7 was 100 % after sham operation and 42 % after GCI. The model of GCI in mice presented in this study compromises the exploratory behavior and resembles the cerebral damage and mortality rate seen after cardiac arrest and/or GCI in man, and is therefore a good model to use for studies of GCI pathophysiology. [ABSTRACT FROM AUTHOR]