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Objective: The goal of this study was to investigate the protective effect of recombinant human EPO(rhEPO) on cerebral microvascular endothelial cells and the mechanisms by which rhEPO interacts with TJs proteins, claudin-5, Occludin and ZO-1 during the early period following traumatic brain injury. Research design: Rats (n = 81) were randomly divided into sham-operated group, TBI group and rhEPO+TBI group. Traumatic brain injury was induced by the Marmarou method. Methods and procedures: Rats were killed at 3, 24, 72 and 168 hours after TBI. The integrity of the blood–brain barrier was investigated by using a spectrophotometer to assess extravasation of Evans blue dye. The expression of Claudin-5, Occludin and ZO-1 were determined by immunohistochemistry and real-time fluorescence quantitative PCR. Results: From 3 hours to 3 days, rats in the TBI group demonstrated a remarkable increase in Evans blue content in the brain, relative to rats in the sham-operated group (p < 0.05). The expression of Claudin-5 and Occludin was significantly lower than those in the sham-operated group (p < 0.05). In contrast, rats in the TBI+rhEPO group demonstrated a significant decrease in brain levels. Conclusion: It was found that administration of rhEPO protected cerebral microvascular endothelial cells and reduced permeability of BBB and the mechanisms may be due to increasing the expression of TJs proteins. [ABSTRACT FROM AUTHOR]

Primary objective: Lipopolysaccharide (LPS) is known to alter the integrity of the blood-brain barrier (BBB) in sepsis, although the underlying mechanism remains unknown. The aim of this study was to elucidate the molecular mechanisms underlying disruption of the BBB in LPS-induced sepsis. Research design: Both in vitro and in vivo experiments were designed to test the role of AMP-activated protein kinase (AMPK) in LPS-induced BBB dysfunction. Methods and procedures: Human brain microvascular endothelial cells (HBMECs) were cultured. The protein expressions were detected by western blot. BBB integrity was determined by Evans Blue. Main outcomes and results: LPS (1 μg ml-1) dramatically increased the permeability of the BBB and the ROS productions, as well as reducing the expression levels of occludin and claudin-5 in cultured HBMECs. Inhibition of NAD(P)H oxidase by apocynin or up-regulation of AMPK reversed the LPS-induced abnormities in HBMECs. In LPS-induced sepsis in mice, it was found that LPS dramatically increased NAD(P)H oxidase protein expressions and ROS productions in the brain and disrupted BBB function assayed by Evans blue staining, which were abolished by AICAR treatment. Conclusions: It is concluded that AMPK activation improves the functions of the BBB impaired by LPS through suppression of NAD(P)H oxidase-derived ROS in mice. [ABSTRACT FROM AUTHOR]