The Effects And Mechanisms Of Cycloxyenase-2 On Apoptosis Of Acinar Cells In Rats With Acute Pancreatitis

Objective To investigate the effects of cycloxyenase-2(COX-2) on apoptosis of acinar cells in rats with experimental acute pancreatitis(AP) and explore the possible mechanisms.Methods Thirty Sprague-Dawley(SD) rats were randomly divided into three groups: group A(shame operation group), group B(AEP group) and group C(AHNP group) each with ten in group. AP model was induced by modified method: acute edematous pancreatitis(AEP) and acute hemorrhagic necrotizing pancreatitis(AHNP) were induced by injection of 0.5% or 5% sodium deoxycholate through retrogradely common biliopancreatic ducts via papilla duodeni with epidural catheter, closed puncture hole with medical sealant glue. Rats were anatomized after 12 hours of injection. Ascites and blood samples were obtained. The pancreatic tissues were harvested for assessing the histopatholonical change, general and histological changes of pancreas was evaluated by the corresponding score system. The apoptosis of acinar cells was measured by TUNEL staining, and the expression of Cox-2, Bcl-2, Bax were determined by immunohistochemical technique.Results1 The serum amylase activity in group A, group B and group C were 1479.10±111.73U/L, 4569.70±423.90U/L, 7116.90±363.83U/L; And AC(P<0.01). In group B and group C, apoptotic index were negatively correlated with general score(B: r=-0.761 P<0.05; C: r=-0.780 P<0.01) and histological score(B: r=-0.763 P<0.05; C: r=-0.664 P<0.05).4 The positive rate of Cox-2 in each group were 0%, 40%, 90%; and AC(χ2=4.96 P<0.05).5 In group B and group C, the expressions of Cox-2 were negatively correlated with the apoptotic index of acinar cells(B: rs=-0.874 P<0.01; C: rs=-0.890 P<0.01).6 In group B and group C, the expressions of Cox-2 were positively correlated with the expressions of Bcl-2(B: rs=0.791 P<0.01; C: rs=0.700 P<0.05); However, negatively correlated with the expressions of Bax(B: rs=-0.687 P<0.05; C: rs=-0.724 P<0.05).Conclusion1 The apoptosis of acinar cells was observed in rats with AP, and negatively correlated with disease severity of pancreatic tissues, which indicating as a self-protection mechanism of individuals with AP.2 The over expression of Cox-2 was observed in rats with AP, and closely related to disease severity of pancreatic tissues, which indicating Cox-2 play an important role in AP developing proceedure.3 The expression of Bcl-2 and Bax were observed in rats with AP, differential expression of them in different individuals closely related to disease severity of pancreatic tissues, which indicating Bcl-2 and Bax were involved with the regulation of the acinar cells apoptosis.4 The over expression of Cox-2 in rats with AP were negatively correlated with the apoptosis of acinar cells, positively correlated with the expressions of Bcl-2, and negatively correlated with the expressions of Bax; Cox-2 may up-regulate the expressions of Bcl-2, down-regulate the expressions of Bax, which inhibiting the apoptosis of acinar cells and deteriorate pancreatic disease.