ACTIVATED GRANULOCYTE INDUCED ALTERATIONS IN RED-BLOOD-CELLS AND PROTECTION BY ANTIOXIDANT ENZYMES

Activated leukocytes generate oxygen free radicals and cause injury in a variety of surrounding cells. Red blood cells (RBC) are among the m ost susceptible cells to this injury. Deformability, lipid peroxidatio n and membrane proteins were investigated in RBC after incubation with activated granulocytes (2 hours, at 37 degrees C), obtained from guin ea pigs with experimental sepsis. A second group of experiments was co nducted with non-activated granulocytes isolated from blood of healthy guinea pigs, RBC transit time through 5 mu m pores measured by a cell transit analyzer was 3.25 +/- 0.12 msec and 2.86 +/- 0.02 msec in the suspensions containing activated and non-activated granulocytes, resp ectively (p < 0.05). Addition of superoxide dismutase (SOD) (20 mu g/m l) and catalase (40 mu g/ml) inhibited the effect of activated granulo cytes on RBC deformability. Lipid peroxidation was also increased unde r the influence of activated granulocytes (31.50 +/- 3.36 nmol/grHb ve rsus 20.02 +/- 2.97 nmol/grHb), SOD failed to prevent this increment, while catalase was found to be effective. A widening of Band 1 (spectr in) was observed in SDS-PAGE electrophoresis of membrane proteins of R BC incubated with activated granulocytes, indicating spectrin-hemoglob in crosslinking. This alteration was prevented by both SOD and catalas e, as in the case of transit time. The superoxide radical seems to be responsible for the membrane protein and mechanical alterations, while lipid peroxidation was induced by a different oxidative mechanism.