| Objective To develop a model of microthrombosis in the rat coronary microcirculation induced by microthrombotic particles; To investigate the mechanism of rat endocardial microvascular thrombosis induced by microthrombotic particles; To evaluation the alterations of cardiac function following coronary artery microthrombosis in rats.Methods The rats were randomly divided into model group, sham group and control group. The model of coronary artery microthrombosis was induced by aortic root injection with 0.2ml microthrombotic particles after clamping the ascending aorta. In sham group, 0.2ml 0.9% Sodium Chloride was injected into aorta after clamping the ascending aorta. The sample was taken 1h, 1d, 1w, 2w, 3w and 4w after operation respectively. A echocardiography was performed to monitor the alterations of rats cardiac function before being executed. The myocardial sections were stained with hematoxylin-eosin, endocardial microvascular thrombosis was observed by the optics microscope and the amount of coronary artery with microthrombosis was calculated. The level of von Willebrand Factor (vWF) in sera was detected with the use of enzyme-linked immunosorbent assay (ELISA). The expression of fgl2 prothrombinase mRNA in the myocardial sections was detected by RT-PCR.Results①Microscopic examination of hematoxylin-eosin stained sections revealed that platelet and fibrin microthrombus formed in the coronary microcirculation, some were conglutinated tightly with microvascular endothelial cells. The amount of coronary artery with microthrombosis in model group was higher than those in sham group, which were (23.06%±1.73%) vs (5.72%±2.02%)(P<0.01); but there was no significant difference between sham group and control group, which were (5.72%±2.02%) vs (2.15%±1.01%)(P>0.05).②The vWF levels in sera increased remarkably 1 hour after operation. fgl2 prothrombinase mRNA was detected in the myocardial sections of model group, its level was highest after 1 hour following operation and it could be detected after 4w following operation continuously. The level of fgl2 prothrombinase mRNA was correlative with the vWF level in sera.③1 day following operation, by comparing model group with sham and control group, FS was decreased (45.95%±1.77% vs 51.8%±3.25%, 57.30%±1.41%, P<0.05), so did EF (82.78%±2.40% vs 90.35%±0.21%, 91.08%±1.07%, P<0.05); 4 weeks following operation, by comparing 4w model group with 1d model group, sham and control group, LVIDd was significantly enlargmented (6.65mm±0.21mm vs 5.25mm±0.21mm, 5.40mm±0.46mm, 4.70mm±0.28mm, P<0.05), FS was significantly decreased (31.60%±0.56% vs 45.95%±1.77%, 51.50%±4.20%, 57.30%±1.41%,P<0.05), so did EF(65.46%±0.48% vs 82.78%±2.40%, 87.81%±2.45%, 91.08%±1.07%, P<0.05).Conclusion 1. Microthrombotic particles injected into aortic root could not only blocked the coronary microcirculation, but also induced rat endocardial microvascular thrombosis. 2. It is suggested that the microthrombotic particles could induce rat coronary artery microthrombosis by activation endocardial microvascular endothelial cells. The coronary artery microthrombosis may be related to the high expression of fgl2 prothrombinase, which could provide a new clew for the diagnosis and treatment of coronary artery microthrombosis. 3. Progressive cardiac remodeling happened following coronary artery microthrombosis and rats cardiac function was decreased gradually. |
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