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. 2013 Jan 7;121(9):1651–1662. doi: 10.1182/blood-2012-02-414037

Figure 1.

Figure 1

Comparison of osmotic fragility, fraction of reduced RBC membrane thiol, and reducing equivalent recycling in normal and SSRBCs after oxidant exposure. (A) NaCl-induced osmotic lysis at baseline and after oxidant exposure (HX/XO) for normal and SSRBCs; half-maximal effective concentration (EC50) increased for SSRBCs alone (n = 3-10). *P < .05, mean ± SEM, is plotted. (B) Free (reduced) membrane thiol for normal and SSRBCs at baseline and after oxidant exposure (HX/XO; n = 6-8). *P < .05 for % loss, normal versus sickle cell. (C) GSH and NADPH Ehc for normal and SSRBCs at baseline and during oxidant exposure (n = 4-6). *P < .05 for normal versus sickle cell (baseline); +P < .05 for normal versus sickle cell (HX/XO exposed comparison); #P < .05 for normal versus sickle cell (HX/XO exposed comparison). At baseline, note that relative to normal RBCs, SS membrane thiol redox poise favors oxidation and GSH and NADPH reducing power is diminished (ie, less negative Ehc). Antioxidant system failure in SSBRCs is evidenced by the rate and degree to which GSH and NADPH reducing power is lost under O2− loading. Moreover, after oxidant exposure, SSRBCs suffer membrane thiol depletion and lose resilience to osmotic fragility (ie, rightward shift).