This study was designed to examine the effects of diamide and thioredoxin (TRX) on vascular endothelial cells in order to clarify the mechanism by which vascular damage is mediated by oxygen free radicals.

The pulmonary artery endothelial cell (PAEC) line derived from bovine serum was cultured for 8 hours in media supplemented with various concentrations of diamide and TRX. The XTT assay, MTS assay, SRB assay, LDH activity and lipid peroxidation tests were perfomed.

In XTT and MTS assays, diamide significantly decreased the cell viability of cultured PAEC in a dose- and time-dependent manner. Diamide showed a decrease in the amount of total protein, although it showed an increase of lipid peroxidation and LDH activity in cultured PAEC. In regards to the protective effect of TRX on diamide-induced cytotoxicity, this showed an increase of total protein, however it showed a decrease of lipid peroxidation and LDH activity.

Our results suggest that diamide has a vasculotoxic effect on cultured bovine PAEC and that TRX is very effective in the protection of diamide-induced cytotoxicity by duye to the increase of total protein and the decrease of lipid peroxidation and LDH activity in these cultures.