Objective      To determine the roles of TNF-α and IL-8 in the delayed apoptosis in polymorphonuclear leukocyte (PMNs) in rats with acute lung injury after acute severe pancreatitis (ASP).       Methods      Twenty-four male SD rats were inflicted with 3.5% taurocholic acid into the biliopancreatic duct to establish ASP rat model complicated with acute lung injury. After injection

these rats were divided into 3

6

12 h groups with 8 rats in each group

and another 24 health rats served as control. At scheduled time

bronchoalveolar lavage fluid from the model and control group was drawn and then PMNs were obtained by gradient density gradient centrifugation. Through flow cytometry

the ratio of apoptosis and necrosis of PMNs was assayed. The expression of NF-κB p65 was detected by immunohistochemical assay. The levels of TNF-α and IL-8 in the bronchoalveolar lavage fluid were determined by ELISA.       Results      The levels of TNF-α and IL-8 in the bronchoalveolar lavage fluid were significantly increased compared with the control and remained higher for a relatively long period (P0.05). The ratio of survival PMNs was increased (P0.05)

indicating that apoptosis was delayed. The expression of NF-κB p65 in lung tissue in the model rats were significantly higher than control (P0.05).       Conclusion      TNF-α and IL-8 might play important roles in acute lung injury after acute severe pancreatitis.