| Using platelets addictive solution (PAS) instead of plasma to preserve platelets can maintain the activities and functions of the platelets, and avoid the dangers of fever, hypersusceptibility, and circulatory overload which will be induced by plasma transfusion. In this study, on the basis of the available PAS , the new type of PAS added metabolism substrates was developed to deliver theoretic foundation and technical support for its application in preservation of platelets.First, ingredients of the new type of PAS were ascertained according to the effects on platelets. Then, the morphology, structure, function of platelets and expression of membrane protein were researched with animal model of SCID mouse. After preserved platelets were separately transfused into the mice, the survival time and recoveries of stored platelets were detected to compare the protective effects of the new type of PAS, plasma and other available PAS. There were four groups in the experimental design: plasma group (group 1), 70% of the new type of PAS (group 2), PASIII group (group 3), and 100% of the new type of PAS (group 4). According to the studies above, ingredients of the new type of PAS was confirmed which includes sodium chloride,potassium chloride,MgCl2,sodium citrate,Na-acetate,Na2HPO4,and glucose. The new type of PAS accounts for 70% of the solution suspending the platelets. Observed under optical microscope and electron microscope, shapes and ultrastructures of stored platelets were intact which were preserved by the new type of PAS. The recoveries of platelets stored to day 5 in the four groups were 85.3%±4.2%,94.5%±1.5%,94.3%±1.3% and 78.3%±6.8% respectively(P>0.05). The activities of congregation induced by ADP were 16.7%±4.4%, 17.1%±3.9%, 22.6%±8.2% and 2.6%±0.4%. (There was distinct differentia between group 4 and the other three groups, P<0.05.) The activities of congregation induced by THR were 78.4%±14.7%, 75.2%±8.1%, 76.0%±7.2%,75.4%±11.0%(P>0.05), with no differentia among them. The pH values of the platelets were 6.7±0.2, 6.9±0.1, 6.8±0.1 and 5.8±0.4 separately. Further studies on the functions of the platelets in group 1, group 2 and group 3 showed that bonding rate of Annextin V to the surface of the membranes were 61.37%±13.1%, 36.23%±4.9% and 46.23%±5.8%. (There was significant differentia between group 1 and group 2, P value<0.05) The expression ratios of CD62P which is a marker for platelet activation were 46.79%±3.7%, 16.14%±4.3% and 28.1%±4.9%. (There was significant differentia between group 1 and group 2, P value<0.05) When the mice platelets stored for 0 day were transfused into the body of the BALB/c mice, the in vivo 24 h recoveries were observed as 18.1%±2.5%, 47.9%±7.5% and 49.2%±10.3% separately in group 1, group 2 and group 3. (There was significant differentia between group 1 and group 2, P value<0.05) When the mice platelets stored to day 1 were transfused, the data were 30.0%±12.3%,44.8%±13.0%,31.1%±15.0%. (Significant differentia between group 1 and group 2, P value<0.05) With platelets stored to day 3, the data were 8.1%±2.2%, 47.9%±13.9% and 26.2%±16.1%. (Significant differentia between group 1 and group 2, P value<0.05) 5 days, 0,7.5%±0.3%,0. The experiment of transfusing human blood to SCID mice demonstrates that the in vivo 4h recoveries of the platelets preserved to day 0 were 37.9%±13.1%, 64.9%±21.7% and 49.6%±10.3% respectively in group 1, group 2 and group 3. With platelets stored to day 1, the data were 17.2%±4.8%, 30.6%±7.9% and 25.1%±7.1%. With platelets stored to day 3, the data were 1.7%±0.6%, 58.8%±18.0% and 12.7%±9.7%. (Significant differentia between group 1 and group 2, P value<0.05) With platelets stored to day 5, the data were 0.2%±0.03%, 1.1%±0.6% and 0.The present study shows that the morphology and structures of the platelets preserved with the new type of PAS are normal, without any distinct difference comparing to the platelets stored in plasma. The detection of the pH value suggests that the new type of PAS has stronger buffer system than plasma. Apoptosis rates of platelets stored in plasma group are higher than that in the new type of PAS, which implies the new type of PAS can improve the protective quality. The measure of activation marker also suggests that the new type of PAS can reduce activation rates during storage. The in vivo recovery of platelets is a golden standard to evaluate the effects of preservation. In this experiment, the results show that the in vivo recoveries of platelets stored with the new type of PAS are higher than which are preserved in plasma or PASIIIM. However, we also notice that the in vivo recovery of platelets preserved in the new type of PAS to day 5 just reaches the value of 7.5%, far lower than the recovery of platelets preserved to day 3 which reaches 47%.In conclusion, through the analysis of comparison among the new type of PAS, plasma and PASIII, we can see that the new type of PAS can effectively protect the morphology, structure and functions of platelets, delay the course of platelets apoptosis and reduce the activation rate of platelets during storage. Platelets still have a long survival time and a high recovery after being preserved. All of those work validate our idea is feasible that the type of PAS can partly substitute the plasma in storing platelets. Using the new type of PAS may resolve many problems happened in the case of using plasma. So, our work can provide scientific and technical supports for the application of PAS in clinic. |
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