Erythrocyte antioxidant systems protect cultured endothelial cells againstoxidant damage.

A study was undertaken to assess the ability of the erythrocyte to protect other tissues against oxidative damage. Radiolabelled (Cr-51) human umbilic al vein endothelial cells (HUVEC) were incubated with erythrocytes and neut rophils activated with phorbol myristate acetate (PMA). Damage to the endot helial cells was indicated by release of radioactivity into the suspending medium. We found that the co-incubation of HUVEC with an increasing range o f erythrocyte concentrations resulted in a dose-dependent reduction in the release of radioactivity. When the ability of superoxide to cross the eryth rocyte membrane or the glutathione systems was inhibited, the extent of end othelial cell damage increased. Inhibition of the catalase system did not a ffect results. It was concluded that the erythrocytes afforded some protect ion against oxidative damage to the endothelial cells by taking up and deac tivating the superoxide ions. This protection depends upon intact erythrocy te antioxidant systems. These data support the hypothesis that erythrocytes can provide antioxidant protection to other tissues in vivo.