Relation of fluorescence in lipid-containing red cell membrane extracts to in vivo lipid peroxidation.

Previous studies have demonstrated that the abnormal fluorescent peak consistent with the crosslinking of red cell membrane constituents by the lipid-peroxide decomposition product MDA is demonstrable in lipid-containing extracts of red cells obtained from patients treated with the oxidizing hemolytic agent diaminodiphenylsulfone. The present studies were primarily aimed at ascertaining the specificity of this fluorescence as an indicator of in vivo red cell lipid peroxidation. Repetitive injection of phenylhydrazine or acetylphenylhydrazine in rats resulted in gradually increasing levels of fluorescence despite the return in hematocrit toward normal. Chromatography on Sephadex LH-20 of lipid-containing extracts obtained from the red cells of rats and rabbits treated with phenylhydrazine revealed fluorescent peaks similar to those observed in red cell lipid incubated with MDA. In addition, increased levels of fluorescence were observed in the extracts of red cells obtained from three vitamin E--deficient premature infants. These findings suggest that the fluorescence assay is a sensitive indicator of in vivo red cell lipid peroxidation.