The Relationship Between Acute Lung Injury And The Procoagulant And Pro-inflammatory Properties Of Red Blood Cell-derived Microparticles In Mice

Objective:The aim of this study is to investigate the procoagulant and pro-inflammatory properties of red blood cell-derived microparticles(RMPs)relrased from red blood cell suspension during storage,and the relationship between these two properties and acute lung injury in mice,so as to further clarify the correlation between RMPs and trandfusion-related acute lung injury(TRALI).METHODS:RMPs were isolated,purified and counted,andthen the contents of the activated partial prothrombin time(APTT),prothrombin time(PT)and thrombin generation test were detected in the plasma of red cell supernatant under the circumstances before and after the removal of the microparticles and different concentrations of RMPs.The effects of erythrocyte supernatant and RMPs on the respiratory burst of fMLP activated PMNs were analyzed by interacting with human peripheral blood PMNs and detecting their average fluorescence intensity.The expression of cell adhesion molecule-1(ICAM-1;CD54)on human pulmonary microvascular endothelial cells(HMVECs)was detected by flow cytometry,to determine the effect of RMPs on HMVECs activation.The levels of thrombin-antithrombin complex and plasminogen activator inhibitor-1 in mouse bronchalveolar lavage fluid(BALF)were measured by ELISA.The extravascular lung water and the total protein content of BALF in mice infused with RMPs orthe pre-and post-filteredred blood cell supernatants were measured.Histological observation of right lung tissue in the experimental group injected with 3×107 RMPs and the control group was conducted.RESULTS:The number of RMPs in red blood cell suspension increased gradually with the prolongation of storage time.As the concentration of RMPs added increased,the APTT value of the degranulated plasma decreased slightly,while the PT value did not change significantly.When erythrocyte supernatant and RMPs with a certain range of concentrations were added tothe plasma,the lag time and tt-peak could be shortened to some extent,while the peak and ETP were increased significantly and had a concentration dependence.RMPs could significantly induce respiratory burst of fMLP activated PMNs,thus inducing RMPS to participate in HMVECs injury.After 6 hours of RMPs induction,the expression of CD54 on HMVECs increased significantly.Compared with the control group,the TATc of BALF was significantly increased in the experimental group injected with 3×107 RMPs,the inflammation of the alveolar tissue was intensified and the procoagulant mechanism was enhanced.The removal of microparticles from red blood cell supernatants could partly inhibit the respiratory burst produced by PMNs,and the infusion of red blood cell supernatants to remove microparticles could inhibit the occurrence of acute lung injury in mice.Conclusion:RMPs can promote thrombin generation and thereby promote systemiccoagulation activity,lead to microvascular endothelial injury,can cause respiratory burst of PMNs and induce acute lung injury in mice,which may be closely related to adverse reactions such as the transfusion-related acute lung injury(TRALI)after blood transfusion in some patients.