Role of peroxiredoxin-2 in protecting RBCs from hydrogen peroxide-induced oxidative stress.

The role of peroxiredoxin-2 (PRDX2) in preventing hydrogen peroxide-induced oxidative stress in the red blood cell was investigated by comparing blood from PRDX2 knockout mice with superoxide dismutase-1 (SOD1) knockout and control mice. Loss of PRDX2 increased basal levels of methemoglobin and heme degradation (a marker for oxidative stress), and reduced red blood cell deformability. In vitro incubation under normoxic conditions, both with and without inhibition of catalase, resulted in a lag phase during which negligible heme degradation occurred followed by a more rapid rate of heme degradation in the absence of PRDX2. The appreciable basal increase in heme degradation for PRDX2 knockout mice, together with the lag during in vitro incubation, implies that PRDX2 neutralizes hydrogen peroxide generated in vivo under the transient hypoxic conditions experienced as the cells pass through the microcirculation.