RESUMO
<p><b>OBJECTIVE</b>The purpose of this study was to assess weather the immortalized mouse brain endothelial cell line Bend.3 displays the comparative barrier characteristics as the primary brain microvascular endothelial cells (BEMC).</p><p><b>METHODS</b>Immortalized mouse brain endothelial cell line, Bend.3 cells were cultured in transwell inserts and their restrictive characteristics were assessed by transendothelial electrical resistance (TEER) and horseradish peroxidase (HRP) permeability assays. Western blot and direct fluorescent staining methods were used to detect the tight junction protein expression and F-actin distribution.</p><p><b>RESULTS</b>The TEER in Bend.3 cells increased with the prolonged culture time and increased to 82.3+/-6.0 Omega cm2 10 days after culture, which was significantly higher than that 3 days after culture (37.3+/-3.1 Omega cm2; P<0.05). There were significant differences in the permeability rates for HRP 3 and 10 days after culture (4.3+/-0.20)% vs (2.2+/-0.05)% (P<0.05). Western blot indicated high level expression of tight junction proteins occludin and ZO-1 in Bend.3 cells 10 days after culture. F-actin was visualized around the cell membrane and presented scrobiculate linear fluorescence 10 days after culture.</p><p><b>CONCLUSIONS</b>Bend.3 cells have similar barrier characteristics to BEMC, and their barrier function may reach to the best effect 10 days after culture.</p>