Fig. 1.
Changes in blood O2 equilibrium curves during normoxia, 10% O2 hypoxia, and 5% O2 hypoxia. Each panel includes arterial (square), arteriolar (circle), and venular (triangle) O2 saturation for each group. BL, baseline; Nor, normoxia (A); Hyp10, 10% O2 hypoxia (B); Hyp5, 5% O2 hypoxia (C). Severe hypoxia was induced by normobaric hypoxia with 10% O2 balanced N2, and, after characterization, the animals were exposed to extreme hypoxia using 5% O2 balanced N2. Reduction of the fraction of inspired O2 limits the amount of O2 bound to the Hb in pulmonary circulation; therefore, increasing hemoglobin (Hb) O2 affinity augments the O2 transported by the blood to the tissues. 5-Hydroxymethyl-2-furfural (5HMF) increased the blood O2 saturation at lower Po2.