AIM:The objective of this study is to elucidate the potentialrole of poly-morphonuclear neutrophils(PMN)in thedevelopment of such a sinusoidal endothelial cell(SEC)injury during early acute obstructive cholangitis(AOC)inrats.METHODS:Twenty one Wistar rats were divided into threegroups:the AOC group,the bile duct ligated group(BDLgroup),and the sham operation group(SO group).Thecommon bile duct(CBD)of rats in AOC group was duallyligated and 0.2 ml of the E.coli O_(111)B_4(5×10~9 cfu/ml)suspension was injected into the upper segment,in BDLgroup,only the CBD was ligated and in SO group,neitherinjection of Eo coli suspension nor CBD ligation was done,but the same operative procedure.Such group consisted ofseven rats,all animals were killed 6 h after the operation.Morphological changes of the liver were observed underlight and electron microscope.Expression of intercellularadhesion molecule-1(ICAM-1)mRNA in hepatic tissue wasdetermined with reverse transcription polymerase chainreaction(RT-PCR).The serum levels of alanineaminotransferase(ALT)were determined with anutoanalygerand cytokine-induced neutrophil chemoattractant(CINC)was determined by enzyme-linked immunosorbent assay(ELISA).RESULTS:Neutrophils was accumulated in the hepaticsinusoids and sinusoidal endothelial cell injury existed inAOC group.In contrast,in rats of BDL group,all thefeatures of SEC damage were greatly reduced.Expressionof ICAM-1 mRNA in hepatic tissue in three groups were 7.54±0.82,2.87±0.34,and 1.01±0.12,respectively.Therewere significant differences among three groups(P<0.05).The serum CINC levels in the three groups were 188±21 ng·L~(-1),94±11 ng·L~(-1),and 57±8 ng·L~(-1),respectively.Therewere also significant differences among the three groups(P<0.05).Activity of the serum ALT was 917±167 nkat·L~(-1),901±171 nkat·L~(-1),and 908±164 nkat·L~(-1),respectively,(P>0.05).CONCLUSION; Hepatic SEC injury occurs earlier than hepatic parenchymal cells during AOC. Recruitments of circulating neutrophils in the hepatic sinusoidal space might mediate the SEC injury, and ICAM-1 in the liver may modulate the PMN of accumulation. AIM: The objective of this study is to elucidate the potential ofleaf poly-morphonuclear neutrophils (PMN) in thedevelopment of such a sinusoidal endothelial cell (SEC) injury during early acute obstructive cholangitis (AOC) inrats.METHODS: Twenty one Wistar rats were divided into three groups: the AOC group, the bile duct ligated group (BDLgroup), and the sham operation group (SO group) .Thecommon bile duct (CBD) of rats in AOC group was duallyligated and 0.2 ml of the E.coli O 111 ) B_4 (5 × 10 ~ 9 cfu / ml) suspension was injected into the upper segment, in BDLgroup, only the CBD was ligated and in SO group, neither injection of Eo coli suspension nor CBD ligation was done, but the same operative procedure. These groups consisted of all rats, all of which were killed 6 h after the operation. Morphological changes of the liver were observed under light and electron microscope. Expression of intercellularadhesion molecule-1 (ICAM-1) mRNA in hepatic tissue wasdetermined with reverse transcription polymerase chain reaction RT -PCR). The serum levels of alanine aminotransferase (ALT) were determined with an autoanalyge and cytokine-induced neutrophil chemoattractant (CINC) was determined by enzyme-linked immunosorbent assay (ELISA) .RESULTS: Neutrophils was accumulated in the hepatics inusoids and sinusoidal endothelial cell injury existed in AOC group. In contrast, in rats of BDL group, all the features of SEC damage were significantly reduced. Expression of ICAM-1 mRNA in hepatic tissue in three groups were 7.54 ± 0.82, 2.87 ± 0.34, and 1.01 ± 0.12, respectively. differences among three groups (P <0.05). The serum CINC levels in the three groups were 188 ± 21 ng · L -1, 94 ± 11 ng · L -1 and 57 ± 8 ng · L -1 ~ (-1), respectively.Therewere also significant differences among the three groups (P <0.05) .Activity of the serum ALT was 917 ± 167 nkat · L -1, 901 ± 171 nkat · L -1 ), and 908 ± 164 nkat · L -1, respectively, (P> 0.05) .CONCLUSION; Hepatic SEC injury occurs earlier than hepatic parenchymal cells during AOC. Recruitments of circula ting neutrophils in the hepatic sinusoidal space might mediate the SEC injury, and ICAM-1 in the liver may modulate the PMN of accumulation.