Figure 2.

Enhanced susceptibility to oxidant and osmotic stress in Per2-null erythrocytes. A, percent survival of WT and Per2-null mice subjected to PHZ-induced hemolysis. Mice were injected with a single dose of PHZ (0.23 mg/g body weight) and monitored for 7 days. Each group consisted of 20 mice. B, decreased hematocrit in Per2-null erythrocytes after exposure to the oxidant PHZ. WT and Per2-null mice were treated with a single dose of PHZ (0.20 mg/g). C, time course of H₂O₂-induced hemolysis of erythrocytes. RBCs were incubated in 2 mm H₂O₂ for the indicated time. The extent of hemolysis was measured as described under “Materials and methods.” D, dose course of H₂O₂-induced hemolysis of RBCs. RBCs were incubated for 2 h in the indicated concentrations of H₂O₂. E, erythrocytes from WT and Per2-null mice were subjected to an osmotic fragility test as described under “Materials and methods.” Results are expressed as the percentage of lysis in graded salt concentrations after a 30-min incubation. F, erythrocytes were incubated in 0.55% NaCl for the indicated time. Results represent mean ± S.D. (error bars); n = 5 in each group; *, p < 0.05; **, p < 0.01.