Antioxidant cocktail attenuates Tat and cocaine-mediated augmentation of endothelial dysfunction.

<p>Effect of antioxidants (A) and catalase or SOD (B) on cocaine (1 µM) and Tat (25 ng/ml) mediated barrier dysfunction of HPMECs. Confluent monolayers were grown on collagen-coated Transwell inserts and treated with antioxidant cocktail followed by Tat and cocaine exposure for 6 or 24 hours. Monolayers were then treated with FITC-dextran and after 15 min the fluorescence in the lower compartment was measured and expressed as percentage of basal fluorescence. (C) Effect of antioxidants on Tat and/or cocaine mediated down-regulation of tight junction protein expression in pulmonary arterial endothelial cells. Cells grown on coverslip were immunostained for TJP-1. (D) Quantification of ZO-1 immunofluorescence using ImageJ software. (E) Western blot analysis of ZO-1 in various cellular compartments. Blot is representative of at least three independent experiments with histogram showing the average densitometry analysis normalized to β-integrin for membrane fraction, β-actin for cytosolic fraction and PCNA for nuclear compartment. The values shown are means (±S.E.M.). *P≤0.001 compared to control; ^@P≤0.001, compared to cocaine and Tat treatment.