The Changes of Occludin in Tight Junction of Blood-Brain Barrier by ROS

Cerebral microvessel endothelial cells that form blood-brain barrier (BBB) have tight junction for maintaining brain homeostasis. Occludin, one of tight junction protein, is crucial for BBB function. induced occludin changes and effects in bovine brain BBB endothelial cells were examined in this study. The decrease of transendothelial electrical resistance (TEER) by was due to disruption of occludin localization. Cytotoxicity test revealed that did not cause cell death below 1 mM within 4 hr. caused intermittent disruption and loss of occludin at tight junctions and occludin disappeared with dose dependent manner from tight junction in confocal laser microscopy. But Western blot revealed that the total amounts of occludin increased by administration. Transmission electron microscopy revealed that the ultrastructure of tight junction was not changed by . These data suggest that functional disruption of BBB by was due to the localized loss of occludin in tight junction, but the expression of occludin increased in order to compensate the disrupted function in BBB.