Initial Studies On Platelet's Function Change By S1P,LPA

Various pathological factors such as heredity , radiotherapy and chemotherapy of tumor, drug reaction, blood loss etc. can all lead to reduce of platelet count or descend of platelet's function. Infusion of platelet is an important measure to release patient's complaint and save patient's life. But infusion of platelet always causes various transfusion reactions, which cause platelet transfusion refractory, PTR). It is a tough problem must to be faced with in clinical, and is also a focal point pay close attention to the field of transfusion. Many extensive fundament and clinical investigations have been done to aim directly at PTR. Though the reasons causing PTR are complex, but the two factors of immunity and non-immunity are generally accepted at present.The factor of immunity is caused by antibodies against donor's platelet present in the recipient's plasma, which can kill the donor's platelet. Non-immunity factors include infection, fever, septicemia, DIC etc.Otherwise, platelet can be activated during collection, centrifuge and storage by the factor of circumstance. These induce storage injury, influence the quality of platelet, and result in PTR. What create activation during storage and which channel cause PTR are become important questions. Up to now, there is no better method to solve the question of ineffective infusion by storage injury.One investigation reveals that the activated platelet delivers the sphingosine 1 phosphate and lysophosphatidic acid, which have some influence on platelet's function during conservation. Endothelial differentiation genes are the same membrane's receptor to LPA and S1P. It can create a series reaction of cell biology. At present, there are members of endothelial differentiation genes be discovered. It is the special receptor of S1P and LPA. By this foundation, we will detect the S1P and LPA created during conservation; observe the creative regularity and its affection to platelet's foundation. We also want to observe the improvement of platelet's function by using the blocking agent to block receptor.First, using enzyme linked immunosorbent assay to observe the create regularity of S1P and LPA. The result showed that: as to conservation time, the content of S1P, LPA continues to increase. Keep detect the platelet for five day, the content of S1P is 1.38±0.17,2.07±0.25,2.78±0.31,3.53±0.28,4.56±0.46(μmol/L)respectively. The content of LPA is 1.74±0.36,2.34±0.60,3.01±0.47,4.11±0.46,4.81±0.43 respectively. In the second part, we observed the changes of platelet's function after adding exogenous S1P and LPA with different concentration. The result displayed that the count of platelet, value of PH, content of lactic all have no disparity by statistics. The ratio of aggregation degree of activation and apoptosis has disparity different groups by statistics. The ultra micro architecture has been obviously changed. In part three, we use receptor antagonist pertussis toxin (PTX) blocking the binding of S1P, LPA with platelet surface receptors, and to observe the amelioration of platelet's function. The results reveal that platelet physico-chemical properties including platelet count, pH, and lactic have no statistical difference among the five groups, and in vitro aggregation, platelet activation, apoptosis and ultra micro architecture are restored by adding PTX. Experimental results are statistically differences (P <0.01).The above results reveal: the content of S1P and LPA increase with conservation. Different content S1P and LPA can induce the function of aggregation descent; increase the degree of activation and apoptosis. It demonstrates that the S1P and LPA is one of the important actors inducing the function descent of storage platelet. This paper concluded that the S1P and LPA can influence the function of platelet by the endothelial differentiation genes; the genes'blocking can block the binding of the receptors. PTX can alter the ratio of aggregation, degree of activation and inhibiting apoptosis during storage of platelet.The investigation indicates that S1P and LPA metabolic products of platelet are the main factors affecting the function of platelet in storage.It is the foundation to investigate the molecular mechanism of platelet's function during the conservation and to research the method and reagent of platelet's storage.