Objective:To evaluate the role of caspase-3 in aggravation of the oxidative stress injury in stored red blood cells (sRBCs) by cardiopulmonary bypass (CPB).Methods:Eight patients with type O blood undergoing valve replacement with CPB were selected, blood samples 7 ml were collected through the central venous catheter before CPB, blood samples 20 ml were collected at 2 h after CPB, and the plasma before and after CPB was obtained after centrifugation. Eight samples of sRBCs 14 ml of blood type O stored for 7-14 days were collected and each sample was divided into A, B, C and D groups with 3.5 ml in each group. Normal saline 30 μl was added to group A and group B, 10% dimethyl sulfoxide 30 μl was added to group C, and 3.5 mmol/L Z-DEVD-fmk solution 30 μl was added to group D. The sRBCs were pretreated in a 37 ℃ water bath for 2 h in the four groups. Then group A was incubated with plasma before CPB, group B, C and D were incubated with plasma at 2 h of CPB, and four groups were incubated for 48 h in a thermostatic oscillator at 37 ℃ and 80 rpm. At 2, 24 and 48 h of incubation, the activity of caspase-3 and concentration of ATP were determined by enzyme-linked immunosorbent assay, the concentrations of glutathione (GSH) and free hemoglobin (FHb) were measured by colorimetry, and the exposure rate of cell membrane phosphatidylserine (PS) was detected by flow cytometry.Results:With the prolongation of incubation time, the activity of caspase-3, exposure rate of PS at cell membrane and concentration of FHb were gradually increased, and the concentrations of ATP and GSH were gradually decreased in the four groups ( P<0.05). Compared with group A, the activity of caspase-3 was significantly increased at each time point of incubation in group B and group C, the activity of caspase-3 was increased at 24 and 48 h of incubation in group D, and the concentration of ATP was decreased at 24 and 48 h of incubation, and the concentration of GSH was decreased and the concentration of FHb was increased at each time point of incubation in group B, group C and group D ( P<0.05). Compared with group B and group C, the activity of caspase-3 was significantly decreased, the concentrations of ATP and GSH were increased, and the exposure rate of PS at cell membrane and concentration of FHb were decreased at 24 and 48 h of incubation in group D ( P<0.05). There was no significant difference in the parameters mentioned above between group B and group C ( P>0.05). Conclusions:Caspase-3 is involved in aggravation of oxidative stress injury in sRBCs by CPB.

Red blood cells (RBCs) are one of the most needed blood products in clinical blood transfusion treatment. At present, RBCs are mainly provided by blood donors, and the contradiction between supply and demand is extremely prominent. Customizable RBCs cultured in vitro bring dawn to solve this contradiction. RBCs can be differentiated and cultured from human induced pluripotent stem cells, immortalized adult erythroid progenitor cells, embryonic stem cells (ESCs), hematopoietic stem cells or the mononuclear cells extracted from umbilical cord blood and peripheral blood. Each method, with its own advantages and drawbacks, are still in the stage of laboratory research. However, according to the current progress, it is not far from clinical application. This paper summarizes the progress in this field.

Objective: To evaluate the effect of compound electrolyte injection on phosphatidylserine (PS) exposure in erythrocytes after blood salvage-retransfusion in dogs. Methods: Twenty healthy mongrel dogs, weighing 10-15 kg, aged 3-5 weeks, were divided into 2 groups (n=10 each) using a random number table method: normal saline group (group NS) and compound electrolyte injection group (group MEI). The process of intraoperative blood salvage-retransfusion was simulated in both groups: femoral vein was cannulated for blood withdrawal until the volume of blood lost was 400 ml, and the shed blood was salvaged by a blood recovery machine.The washing solution was normal saline in group NS and compound electrolyte injection in group MEI.The erythrocytes were retransfused after being labeled with fluorescein isothiocyanate.Blood samples were obtained before and after blood salvage for determination of erythrocyte ATP content by enzyme-linked immunosorbent assay.Blood samples were obtained at 24, 48 and 72 h after blood retransfusion, and the PS exposure rate of the salvaged erythrocytes was determined by flow cytometry.The spleen was taken at 72 h after retransfusion to detect the phagocytosis rate of salvaged erythrocytes by monocytes. Results: There was no significant difference in ATP content before and after blood salvage between the two groups (P>0.05). Compared with NS group, the PS exposure rate of the salvaged erythrocytes at each time point after retransfusion and phagocytosis rate of salvaged erythrocytes by monocytes were significantly decreased in MEI group (P<0.05). Conclusion Compound electrolyte injection as a washing solution for intraoperative blood salvage can reduce the PS exposure in salvaged erythrocytes and is helpful in prolonging the lifespan of erythrocytes after retransfusion in dogs.