Ozone-initiated changes in erythrocyte membrane and loss of deformability

In vivo O3 exposure followed by in vitro incubation was observed to cause inhibition of mouse RBC deformability. The requirement for in vitro incubation to allow expression of these effects and the potential role for oxidizable membrane components were investigated. Membrane sulfhydryls (SHs) and membrane ATPase are both susceptible to oxidation by O3 and are essential for maintaining RBC membrane deformability. RBC SH levels and ATPase activity were unchanged immediately after exposure of mice to filtered air (controls) or 1 ppm O3. After a subsequent 6-hr in vitro incubation, RBCs from control mice exhibited significant increases in membrane SH and ATPase activity, while SH levels and ATPase activity in RBCs from O3-exposed mice remained unchanged. Although the stimulus for increasing membrane SH and ATPase activity is unclear, these changes appear to be essential to maintaining RBC deformability in vitro and are inhibited by in vivo O3 exposure.