Researches On Early Change Of Blood Markers In Pulmonary Thromboembolism And Pulmonary Ischemia Reperfusion Injury During Thrombolytic Therapy

【Backgrounds and objectives】Pulmonary thromboembolism is a very common disease with high morbidity and mortality in clinical practice. Early diagnosis, early treatment and improving the prognosis of patients with pulmonary thromboembolism remain challenges of clinical work. How can we establish diagnosis of pulmonary thromboembolism at early stage? How does ischemical reperfusion injury generate after pulmonary thromboembolism? What can we do to avoid ischemical reperfusion injury? In order to approch the above problems, we studied the changes of D-dimer and LDH isoenzymes after experimental pulmonary thromboembolism and evaluated their value for the early diagnosis of pulmonary thromboembolism. We also studied the changes in tissue plasminogen activator (t-PA) and inhibitor-1(PAI-1) expression in pulmonary artery after acute pulmonary thromboembolism. Meanwhile, We investigated the change of superoxide dismutase (SOD), malondiadehyde (MDA), wet to dry lung weight ratio and ICAM-1, which revealed the mechanism of ischemical reperfusion injury. In addition, we used puerarin as intervention to treat the ischemical reperfusion injury.【Methods】(1)Thrombin and human fibrinogen were delivered into clots in the embolism group to establish pulmonary thromboembolism models. The plasma levels of D-dimer were measured by the method double antibodies ELISA. The serum levels of LDH isoenzymes were measured by rapid electrophorosis. (2)The expressions of tissue plasminogen activator and inhibitor-1 were measured by immunohistochemical and western blot in the obstructed pulmonary artery. (3)Serum gained by centrifugalization was uesd to detect SOD and MDA. The mRNA expression of intercellular adhesion molecule-1 was detected by immunohistochemistry and RT-PCR.【Results】(1)The plasma D-dimer level was elevated at 30min after embolism, increased to the highest at 1 to 2 hour , and then decreased at 24 hour. The changes of the levels of LDH3 were the most significant in that of LDH isoenzymes. The serum levels of LDH3 increased at 4 hour after embolism. And up to the highest at 24 to 48 hour , then decreased at 3 to 4 day after embolism.(2)t-PA was stained in the endothelial cells of the morbid pulmonary artery 8h after PTE but not in normal or morbid pulmonary artery 4h after PTE. Staining data was supported by Western blot data. Immunohistohemical revealed PAI-1 staining in the endothelial cells of the normal and the morbid pulmonary artery 24 after PTE but little in morbid pulmonary artery 4h and 8h after PTE. The staining data was also supported by Western blot data.(3)Pathology results and the changes of SOD,MDA,lung W/D ratio showed the lung ischemical reperfusion injury. RT-PCR revealed ICAM-1 mRNA expression in sham group was negative, the expression in urokinase group was higher than that in thrombolysis-only group, and the expression in puerarin group was lower than that in urokinase group,the results were almost consistent with those of immunohistochemistry.【Conclusions】(1)To monitor the levels changing dynamically of the plasma D-dimer and the serum LDH3 were benefited to the diagnosis of pulmonary thromboembolism in the early stage.(2)The fibrinolysis activity was enhanced greatly at the early state of pulmonary thromnoembolism in rabbit, the balance between t-PA and PAI-1 is shifted which might be helpful for lysis of the embolus.(3)The pulmonary reperfusion injury may occur during the thrombolytic therapy of rabbit acute pulmonary thromboembolism and ICAM-1 expression was enhanced; Puerarin may relieve pulmonary reperfusion injury by antioxidation and inhibiting expression of ICAM-1.