The Study Of The Anti-thrombotic Function And Mechanism Of Loureirin A In Rats

Background: With the intensifying of aging society, the thrombotic disease is becoming a common disease, which not only declines the life quality, loses the labor function and increases the psychological burden and other issues, but also becomes a serious threat to the safety of patients. The prevention and treatment of thrombotic diseases has become the attention’s focus around the world. Discovering and enriching the antithrombotic drug is a significant medical research. The Dragon’s Blood is resin obtained by Dracaena cochinchinensis(Lour) S.C.Chen, which is a lipid-containing wood. The Dragon’s Blood includes flavonoids, volatile oils, phenols, cardiac glycosides, polysaccharides and other chemical components. The flavonoids mainly contain Loureirin A and B. Long-term clinical application demonstrates Dragon’s Blood has the effects of blood circulation, analgesic, antispasmodic, anti-inflammatory and hypoglycemic. With the development and utilization of the Dragon’s Blood, the clinical applications become more widely. Isolating the effective active substance and making into new forms will contribute to the Dragon’s Blood to play a good role, which has a good market prospects. However, the Dragon’s Blood has the problems of pharmacological activity and mechanism of action is unknown and the quality standard is imperfect. Therefore, we choose the loureirin A as the research object, to research the affect of thrombosis in rats and its mechanism.Aim:Discuss the anti-thrombotic function and anti-platelet aggregation mechanism of Loureirin A.Method:Part I: Establish the model of thrombus in rats and give drugs by groups. Study the impacts on different indicators of Loureirin A to explore its anti-thrombotic function.Specific methods are: Establish the arteriovenous shunt thrombus model to study the effects of Loureirin A on the formation of thrombus in vitro and in vivo by measuring the thrombus’ s wet weight, dry weight and thrombus inhibition rate; measuring the APTT, TT and PT, to study the impacts of Loureirin A on the coagulation function in vitro; establish the acute thrombus model, to study the effects of Loureirin A on the blood rheology by detecting the whole blood viscosity(low-cut, medium-cut and high-cut), plasma viscosity, hematocrit, fibrinogen, and erythrocyte electrophoresis; establish the acute thrombus model, to study the effects of Loureirin A on the function of platelet adhesion and aggregation by measuring the rate of platelet adhesion and aggregation inhibition rate. Part II: Preincubate and wash the platelets in 5 minute with drug or vehicle. Split the platelets after the aggregation each group. Use Western blot to observe the effect of each group on P-AKT(Ser473 / 474), and to analyze the results’ difference of each group. The experiment is repeated at least three times. Statistical Methods: Use SPSS19.0 statistical software. The measurement information and data are presented as mean ± SD. Use one-way ANOVA to analyze the differences between groups are statistically significant or not.Results:1. Loureirin A with high-dose, medium-dose, low-dose and aspirin reduce the thrombus’ s wet and dry weight in vivo and vitro(p<0.05). The thrombus inhibition increased with the increasing dose of Loureirin A(p<0.05); 2. Loureirin A with three different doses and aspirin are able to extend the APTT(p<0.05). Loureirin A with high-dose, medium-dose and aspirin can extend the TT(p<0.05). Loureirin A with high-dose and aspirin can extend the PT(p<0.05); 3. Different doses of Loureirin A and aspirin can reduce blood viscosity, plasma viscosity, hematocrit and fibrinogen levels(p<0.05). However, the increase was not significant on erythrocyte electrophoresis(p>0.05); 4. The function of reducing platelet adhesion on different doses of Loureirin A and aspirin is weak(p>0.05). But, the Loureirin A significantly inhibits the platelet aggregation(p<0.05).5. Loureirin A can inhibit the AKT’s phosphorylation stimulated by collagen(p<0.05).Conclusions:Loureirin A can inhibit the formation of thrombus in vivo and vitro. It can prolong the clotting time in vitro, reduce the blood viscosity, plasma viscosity, hematocrit and fibrinogen levels, and significantly inhibit the platelet aggregation. What’s more, Loureirin A may play a role in inhibiting the PI3K-AKT pathway to inhibit the platelet aggregation.