[Role of cyclooxygenase-2 in pulmonary microcirculation disorder in rats with acute pancreatitis].

Objective To identify the expression of Cyclooxygenase-2(Cox-2)in lung tissues and its potential role in pulmonary microcirculation disorder in rats with acute pancreatitis. Methods The acute hemorrhagic and necrotic pancreatitis (AHNP) model was induced by the standard retrograde infusion of bilio-pancreatic duct with 4% sterile sodium taurocholate solution in Sprague-Dawley rats. The rats were randomly allocated into sham surgery group, AHNP group, and prophylactic celecoxib treated AHNP (C+ AHNP) group. The HE, phosphotungstic acid hematain (PTAH) and immunohistochemistrical (IHC) staining were employed to assess the dynamical alterations and interrelations of the histopathology, density of micro-thrombus and Cox-2 expression of lung tissue respectively over a time course of 3, 6, 12 and 24 hours. Results A significant and progressing increase in histopathologic scoring and Cox-2 expression in the lung tissues were found. There was a positive correlation between the Cox-2 expression and the histopathological scoring. A significant increase of pulmonary micro-thrombosis was detected at the early stage of the rat AHNP induced by sodium taurocholate, and the density of micro-thrombus was positively associated with the histopathological scoring. The prophylactic treatment with celecoxib, a highly selective inhibitor of Cox-2, attenuated the changes in histopathology, pulmonary micro-thrombosis and Cox-2 expression(P0.05). The down-regulated intensity of the Cox-2 expression by celecoxib was positively correlated with the improvement of the histopathology injury, but not with the change of the pulmonary micro-thrombosis. Conclusion The pulmonary microcirculation dysfunction caused by micro-thrombosis is an early event or even an enabler of the development of APALI. The over-expression of Cox-2 may have promoted the procoagulant activity which plays a key role in the development of pulmonary thrombus.