RESUMEN
Objective The aim of this study is to demonstrate the pathological characteristics about two types of pancreati‐tis ,providing new thinking about the mechanism of severe acute pancreatitis .Methods Thirty male Sprague‐Dawley rats were ran‐domly divided into three equal groups :sham‐operated (SO ,n=10) group ,mild acute pancreatitis (MAP ,n=10)) group and severe acute pancreatitis (SAP ,n=10) group ,all the rats were killed after 12 h of building model .Under the microscope ,we detected the pathological changes of pancreas ,liver ,lung and small intestine .The ultrastructure of pancreas ,liver ,lung and small intestine tissue were observed by transmission electron microscope .Results In SAP group ,congestion ,edema ,inflammatory cell infiltration ,lea‐king of blood componedts ,vascular endothelial injury and thrombosis of microcirculation were obviously observed .There is no ap‐parent pathological changes in the MAP group except the edema of pancreas .Conclusion Hemorrhage and necrosis are the main pathological characteristics in SAP rats ,has essential difference with MAP .These pathological characteristics provides us a new thinking for further study about the mechanism of SAP .