Objective To explore the relationship between the severity of experimental acute pancreatitis (AP) and the expression of Myc interacting zinc finger protein 1 (MIZ1) in rat, to evaluate the value of MIZ1 for severity assessment .Methods Acute necrotizing pancreatitis ( ANP) model was induced by retrograde injection of sodium taurocholate into the pancreatic duct , and normal saline was used in control group.The rats were sacrificed at 6, 24, 48 h, and the blood and pancreas tissue was collected , and serum amylase level , C reactive protein ( CRP ) , TNF-α, IL-6 and MIZ1 were determined by ELISA .Pancreatic tissue was routinely examined by pathologist , and the MIZ1 protein expression in pancreatic tissue was measured by immunohistochemistry and Western blot .Results The serum amylase levels of control group and ANP group at 6, 24, 48 h were (449 ±40), (578 ±25), (1 021 ±205), (971 ±143)U/L, and the levels of CRP were (123 ±23), (169 ±25), (226 ±34), (229 ±24)mg/L;and the levels of IL-6 were (20.16 ± 4.11), (38.60 ±12.05), (52.33 ±6.77), (44.83 ±4.30)ng/L;and the levels of TNF-αwere (55.33 ±3.32), (82.8 ±5.26), (120.66 ±16.00), (108.33 ±12.17)ng/L;and the levels of MIZ1 were (5.51 ± 0.34), (3.44 ±0.56), (2.11 ±0.11), (2.41 ±0.43) ng/L.The pathologic scores of pancreas were (1.83 ±0.75), (6.00 ±1.67), (8.16 ±2.70), (9.33 ±1.50), and the expressions of MIZ1 in pancreatic tissue were 0.81 ±0.05, 0.53 ±0.07, 0.31 ±0.06, 0.21 ±0.08.Except for amylase level of ANP 6h group, other parameters of ANP group were significantly different with those of control group , and the parameters of ANP 24, 48 h group were significantly different with that of ANP 6 h group ( P<0.01), but there was no significantly different between ANP 24 and 48 h group.MIZ1 expression was negatively correlated with serum amylase level , CRP, TNF-α, IL-6 and pathologic scores of pancreas , and the difference was statistically signific ant (P<0.01).Conclusions The decreasing expression of MIZ1 is closely correlated with the severity of AP , and may be a potential marker for prognosis evaluation .