Fig. 4

In vivo transfusion studies demonstrating post-transfusion RBC recovery rate. A During storage, PS expression on the RBC surface can promote RBC adhesion to endothelial cells, leading to RBC clearance by macrophages. Consequently, outer leaflet PS exposure on the RBC membrane acts as an ‘eat-me’ signal. B Overview of the experimental setup for rabbit transfusion studies. Preparation of allogeneic RBC concentrates from donor rabbits and transfusion. New Zealand white rabbits were acquired and subjected to a series of steps for blood collection, centrifugation, and purification. Once prepared, the RBCs were stored under supercooling preservation. Following specific time intervals, RBCs were marked with CFSE⁺ and transfused back into the rabbits. C Morphological analysis of transfused RBC using blood smears. The morphological changes of rabbit RBC in control group and supercooling group with storage time. Red arrow: irreversible changes (sphero-echinocytes and fragmented RBCs). Scale bar = 10 µm. D Flow cytometry plots showing CFSE⁺ RBC labeling. E Recovery rates of RBCs stored at 4 °C versus supercooling conditions over 35 days. RBCs recovery in vivo after transfusion 24 h of supercooling preserve and control preserve on the 0, 14, 21, 28 and 35 days. Data are shown as the mean ± SD from three biological replicates (n = 3). independent samples t-test, *p < 0.05; ns, nonsignificant