치밀이음부 구조단백질인 Occludin에 대한 활성산소종의 영향

초록

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. H2O2 induced occludin changes and effects in bovine brain BBB endothelial cells were examined in this study. The decrease of transendothelial electrical resistance (TEER) by H2O2 was due to disruption of occludin localization. Cytotoxicity test revealed that H2O2 did not cause cell death below 1 mM H2O2 within 4 hr. H2O2 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 H2O2 administration. Transmission electron microscopy revealed that the ultrastructure of tight junction was not changed by H2O2. These data suggest that functional disruption of BBB by H2O2 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.

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