A Study Of The Level Of Cyclooxygenase-2 And Urokinase-type Plasminogen Activator In The Left And Right Atrium Of Acute Atrial Fibrillation In Canines

Objective: The purpose of this study was to investigate the expression of Cyclooxygenase-2(COX-2) and Urokinase-type plasminogen activator (u-PA) in right and left atrial appendages in canine acute atrial fibrillation (AF) model, and discuss the possible relationship with AF-related thromboembolism.Methods: Twelve adult mongrel canines were randomly divided into rapid atrial pacing (RAP) group (n=6) and sham control (SC) group (n=6). A model of acute AF in RAP group has been developed. Cellular structural changes were studied by light and electron microscope in atrial endothelium taken from right and left appendages. Immunohistochemistry was performed to detect the changed expression of the COX-2 and u-PA expression at the protein level in endothelium of atrial appendages.Results: (1) Paroxysmal AF was induced in all of the canines of RAP group. (2)HE stain showed no cellular structural change in both of RAP and SC groups. (3) Compared with SC group, the loss of endothelial cell in the atrial endothelium in RAP group in electron microscope study has been found. (4) Immunohistochemistry study indicated that in RAP and SC groups, the rate of COX-2 expression was 83.3%(10/12) and 25.0%(3/12) respectively. COX-2 expression was significantly stronger in the former (p=0.013). The rate of u-PA expression was 0.0%(0/12) and 75.0%(9/12) respectively, which was significantly lower in the former (p< 0.001 =.Conclusion: Acute AF in canines led to ultra structural changes in the atrial ndothelium. COX-2 protein expressed in RAP group showed inflammation...