Objective To study the expression of aquaporins-4 (AQP4) in the brain tissue of rats with pancreatic encephalopathy (PE) induced by phospholipase A2 and to explore the role of aquaporins-4 in PE.Methods Twenty five healthy Wistar rats were randomized into 3 groups:blank group ( n =5),PE group (n =10 ) and control group (n =10 ).The experimental model was established in rats by injecting phospholipase A2 into carotid artery (0.1 ml/100 g body weight).Same amount of normal saline was used in the control group and no treatment was used in the blank group.One day later,the rats were sacrificed,then the measurement of brain tissue wet/dry (W/D) weight ratio was performed,and brain tissue was routinely pathologically examined,immunohistochemistry and Western blotting were performed in each group to detect the expression of aquaporins-4.Results There was no obvious brain tissue pathological change in the control group and blank group.Neurons in the brain tissue of PE rats presented with significant edema and ballooning degeneration,infiltration of inflammatory cells,leukocyte aggregation around the microvessels.The water contents in the brain tissue in the blank group and control group,PE group were (61.44 ±0.36)％,(63.20±0.32)％ and (78.33 ±0.24)％,and it was significantly higher in PE group than that in the control and blank group (P＜0.05).The expressions of aquaporins-4 in the brain tissue were 0.41 ±0.27,0.49 ±0.13,0.98 ±0.21,respectively,and it was significantly increased in PE group than that in the control and blank group (P ＜ 0.05 ).Conclusions Aquaporins-4 may play important roles in the pathogenesis of pancreatic encephalopathy.