Effect of LDL derived from heme-, metHb-, or ferroHb- and activated PMN–containing plasma on endothelial cell cytotoxicity.
LDL derived from heme-, metHb-, or ferroHb- and activated PMN–containing plasma provoke endothelial cell cytotoxicity. (A) Confluent endothelial cells were incubated with native LDL (200 μg/mL protein) (first bar) or LDL isolated from plasma containing 80 μM heme (second bar), 20 μM ferroHb (third bar), 20 μM metHb (fourth bar), 80 μM metmyoglobin (fifth bar), 80 μM cytochrome c(sixth bar), 20 μM cyanometHb (seventh bar), or 20 μM metHb liganded to haptoglobin (eighth bar) in medium 199 for 4 hours followed by MTT assay as described in “Materials and methods.” (B) Endothelial cells were exposed to native LDL (first bar); to LDL derived from plasma containing 20 μM ferroHb (second bar); 20 μM ferroHb and 500 ng/mL PMA-activated PMNs (107/mL) (third bar); or PMA-activated PMNs alone (fourth bar); to LDL from plasma containing 20 μM ferroHb and resting PMNs (fifth bar); or to LDL from plasma containing 20 μM ferroHb and PMA (sixth bar). After a 4-hour incubation with LDL (200 μg/mL protein), MTT assays were performed. Results represent the percentage of specific cytotoxicity (mean ± SE) of at least 3 experiments done in duplicate.
