HIGH METABOLIC RATES OF 4-HYDROXYNONENAL IN BRAIN CAPILLARY ENDOTHELIAL-CELLS DURING HYPOXIA REOXYGENATION/

We measured the accumulation of 4-hydroxynonenal (HNE), a major lipid peroxidation product during hypoxia/reoxygenation of brain capillary e ndothelial cells (BCEC). The concentration of HNE after 2 h of hypoxia was 0.23 nmol/mg protein and rose up to 0.28 nmol/mg protein after 30 min of reoxygenation. That reflects a 1.5-fold increase, whereas aort ic endothelial cells (AEC) increased the HNE level 5-fold, compared to the control. Therefore, the ability of BCEC to degrade exogenously ad ded HNE was tested. The HNE consumption in BCEC achieved a rate of abo ut 600 nmol . min(-1). mg protein(-1), about two times higher than in AEC. The higher ability of BCEC to degrade HNE is probably the reason of the 2-fold higher IC50 value against the aldehyde. Therefore, we co ncluded that the high ability of BCEC to degrade HNE is a substantial part of the secondary antioxidative defense of the brain.