The Role Of 5-Hydroxtryptamine On Cell Proliferation, Anti-apoptosis And Its Mechanisms In Megakaryocytes

Background and Objective: Thrombocytopenia is a common clinical syndrome, with the develop of tumour treatment such as chemotherapy and stem cell transplant, 5 years survival rate of cancer patients is much higher than before. Side-effects and complications are common reasons that lead to death of cancer patients. Thrombocytopenia is one main complication of cancer treatment, and its mortality is high relatively. Platelets transfusion is a effective and broadly used means to correct low platelets state quickly, though it can induce anti-platelets antibody and invalidate platelets transfusion if reduplicative application. Therefore it is usually difficult to manage for thrombocytopenia at the late stage. How to promote platelets counts quickly and avoid antibody produce and other untoward reaction have become a clinical problem eagerly to be resolved. These years, with the discover of some cytokines such as granulocyte-clone stimulate factor(G-CSF), granulocyte monocyte-clone stimulate factor(GM-CSF) and erythropoietin(EPO), agranulemia and anemia can be cured with a better therapeutic effect, it may also bring a new way for the therapy of thrombocytopenia. In 1994, thrombopoietin (TPO) was purified, but the unexpected functions of inducing antibody and activating platelets greatly limit its clinical application. And the effectiveness of promoting platelets is not as it is expected before. Because proliferation and differentiation of megakaryocyte and platelets produce are special physiological processes, it is important to find a new substance to replace or assist TPO and accelerating recover of platelets for clinic demand.5-Hydroxtryptamine(5-HT, Sertonin, C₁₀H₁₂N₂O)is an indolemine compounds ,being neurotransmitter and vasoactive agent, it has important functions in both central nervous system and peripheral organs. Nemecek et al in 1986 firstly reported that 5-HT can stimulate cardiovascular smooth muscle cell proliferation. Later researches identified that 5-HT is a grow factor and has mitotic function in many cell kinds. Confined by the blood brain barrier(BBB), 5-HT in central nervous system is not exchange with witch in other peripheral organs. About 98% of serotonin of circulation is stored in the dense granules of platelets. 5-HT is a important content of platelet dense granules, it can be released into the blood stream when platelets are activated and cause blood vessel constrict, platelets assemble. Therefore 5-HT is closely with platelets and megakaryocytes, and has important roles in the hemostasis...