Oxygen transport properties in malaria-infected rodents - A comparison between infected and noninfected erythrocytes

Abstract

This study was performed to investigate oxygen transport properties in whole blood (WB) of malaria-infected rats as well as in infected erythrocytes (IE) and noninfected erythrocytes (NIE) separated by density centrifugation. One week after inoculation with Plasmodium berghei, mean parasitemia was 26.5% and high correlations were found between parasitemia and hemoglobin concentration ([Hb]; r = -.902), mean cellular Hb concentration (MCHC; r = - .712), MetHb (r = .923), and base excess (r = -.922). Compared with control animals (C), the oxygen affinity was lower in WB under standard (pH 7.40) and simulated 'in vivo' (pH 7.00) conditions (difference in P50, 5.7 and 5.1 mm Hg, respectively; 2P < .01, 2P < .001), which correlates with lower [2,3-BPG], increased MetHb content, and higher intrinsic Hb-O2 affinity. However, at pH 7.00, the oxygen affinity was lower in IE when compared with NIE, which was most likely due to high [ATP] in IE. The resulting Bohr coefficients (BC) calculated for CO2 and lactic acid were extremely high in IE and low in NIE (at 50% O2- saturation BC(CO2): IE -1.04 ± 0.06, NIE -0.26 ± 0.10, 2P < .001; BC(Lac): IE -0.82 ± 0.16, NIE -0.47 ± 0.07, 2P