ZIGI mouse model: experimental scheme and measure of RBC half-life. (A) Experimental scheme. Inflammation was obtained by a first intraperitoneal injection of 40 μg of LPS followed 6 days later by a single intraperitoneal injection of 0.8 mg/g zymosan. The day of zymosan injection is considered as day 1 and referred to as Z1. ZIGI mice were killed at various time points: Z5, Z9, Z12, and Z17. Intraperitoneal injections of 200 IU of Epo were performed on 4 consecutive days starting at Z5. Mice were analyzed one day (Z9Epo1), 4 days (Z12Epo4), or 9 days (Z17Epo9) after the final injection. Control naive mice received the Epo injections on 4 consecutive days (days 1-4) and were analyzed 1 day (Epo1) or 4 days (Epo4) after the final injection. (B-D) RBC turnover after zymosan injection. Biotin was injected on 3 consecutive days, and zymosan was injected 1 day after (day 1). At the indicated times, a small aliquot of blood was analyzed by streptavidin labeling to detect the decay of biotinylated erythrocytes over time; n = 2 for control mice and n = 3 for ZIGI mice. (B) Representative histograms of data from one mouse in each group are shown for day 1 to day 21. (C) Remaining biotinylated RBCs at different time points after zymosan injection, expressed as percentage of the total circulating RBCs. The decay curves are shown for 2 control mice and 3 ZIGI mice. (D) Correlation between Hb level of the 2 control and 3 ZIGI mice (at Z5) and the measured RBC half-life. Statistical significance was analyzed by linear regression.