ObjectiveTo investigate The role of tumor necrosis factor-α (TNF-α) in pancreatitis-associated adrenal cells' apoptosis of severe acute pancreatitis (SAP). MethodsForty Wistar rats were randomly divided into sham operation group (SO group) and SAP group by random number method, the SAP group was divided into 3, 6, 12, and 24 h 4 subgroups, 8 rats in each group. SAP model was induced by retrograde injection of 5% sodium taurocholate into the bilipancreatic duct. At 3, 6, 12, and 24 h after operation, serum amylase and lipase was measured, adrenal injury was evaluated by histological examination, apoptosis of the adrenal cells was observed by TUNEL method, and expressions of TNF-α and Caspase-3 protein were detected by Western blot. ResultsThe levels of serum AMY and LIP, histopathological scores of pancreatic tissues and adrenal tissues at each time point after operation in SAP group increased significantly than SO group (P < 0.05). With the duration extension of SAP, the apoptosis index of adrenal cells in SAP group progressively heightened, and were higher than those in the SO group (P < 0.05). And the expressions of TNF-α and Caspase-3 protein in adrenal tissues of SAP group gradually increased, at 24 h this data slightly decreased, but still higher than SO group (P < 0.05). ConclusionTNF-α may be involved in the pathogenesis of adrenal injury in SAP rats by activate the protein expression of Caspase-3.