A Serial Study Of Hepatic Ischemia/reperfusion Injury On Cell Death Patterns And Protection Of Hepatocyte In Rats With Obstructive Jaundice

Part 1 A serial study of hepatic ischemic reperfusion injury on cell death patterns in rats with obstructive jaundiceAbstract ObjectiveWe are used to classifying cell death as apoptosis and necrosis, however, it has been a new recognition that cell death patterns are oncosis and apoptosis, necrosis is just a change of morphology after oncosis and apoptosis since Majno produced cell oncosis in 1995. Previously Miyoshi etc. considerd that the main pattern of hepatic cell death after obstructive jaundice was cell apoptosis, nevertheless recent research on obstructive jaundice found that oncosis but apoptosis is the main pattern of hepatic cell death, obviously the two completely contrary results suggestion that there is no final conclusion of hepatic cell death pattern when obstructive jaundice. Besides, literature reported inflammatory reaction occurred in cell oncosis but not in cell apoptosis. Therefore we infer that reducing hepatic cell oncosis is more significant than decreasing apoptosis, but it is deficient in study of hepatic ischemia/reperfusion injury on cell death patterns in condition of obstructive jaundice especially on oncosis. For this reason identifying the very pattern - oncosis, apoptosis or both but one is principal on cell death in hepatic ischemia/reperfusion injury when obstructive jaundice has significance of searching ways to reducing hepatic cell death and relieving hepatic ischemia/reperfusion injury when obstructive jaundice.This experiment uses obstructive jaundice - hepatic ischemia/reperfusion/ biliary tract recanalization rat model to investigate hepatic cell death patterns in obstructive jaundice and hepatic ischemia/reperfusion injury after obstructive jaundice, to provide a new evidence of the mechanism of hepatic ischemia/reperfusion injury after obstructive jaundice, to prepare for the following study of hepatic ischemia/reperfusion injury protection of hepatocyte with obstructive jaundice.Methods27 male Wistar rats were divided into three groups randomly: simulation operation group ( SO group) and obstructive jaundice group ( OJ group) had 5 rats each, obstructive jaundice complicating with hepatic ischemia/reperfusion group ( OJ - IR group) had 17 rats. Obstructive jaundice models were set up according to Yoshidomes maneuver to ligate and cut rat common bile duct. A week later, hepatic ischemia/reperfusion model were established by blocking porta hepatis for fifteen minutes on the basis of Pi-ingle's maneuver. During reperfu-sion, biliary tract recanalization was performed to produce Ryan model. The materials were gained at the time of 0,1,6,24 hours after hepatic reperfusion.An auto analyzer was used to determine serum bilirubin, ALT, AST and LDH level;HE and electron microscope were used to observe cell morphous, hepatic cell apoptosis and oncosis;while flow cytometry are used to count the percentage of hepatic cell apoptosis and oncosis in order to reveal hepatic cell patter.Results1. Ischemia/reperfusion injury to liver with obstructive jaundice;detecting serum ALT,AST,LDH,TBIL,DBIL,UDBIL, ALP and 7 - GT level at 1,6,24 hour demonstrates ischemia/reperfusion injury to liver with obstructive jaundice. Compared with OJ group, serum AST, ALT and LDH level in OJ - IR group are higher than OJ group, it stated that hepatocyte injury aggravated. Since OJ - IR group serum TBIL, DBIL, UDBIL, ALP and7 - GT level are higher than OJ group, it had no meaning in statistics, P >0.05.2. HE manifestation: in OJ group most biliary ductulis broaden and midrange hyperplasy, neutrophil infiltrates appearently. Desmoconnective tissuehyperplasy. A great number of hepatic cells are oncosis, and apoptosis is limited. Hepatic sinusoid becomes narrow, where many RBC and neutrophil appear. When hepatic ischemia stops (reperfusion does not start) , hepatic cell oncosis increases correlation with OJ group, after reperfusion hepatic cell oncosis raises in OJ - IR group. Especially after 6 hours of reperfiision, a large area of hepatic cell oncosis are seen near central vein and neutrophil infiltrates. After 24 hours of reperfusion, hepatic cell swelling reduces, but apoptosis increases and neutrophil infiltrates a little.3. Electron microscope observation: both apoptosis and oncosis appear in OJ group and OJ - IR group, and oncosis in OJ - IR group is obvious, especially 24 hours later when reperfusion.4. Flow cytometry count: there is a little hepatic cell apoptosis and oncosis in SO group, compared with SO group, the percentage of cell oncosis and necrosis increases in OJ group and OJ - IR group ( P <0. 05) , meanwhile cell apoptosis decrease in OJ group but increase in OJ - IR group, the result has no statistics meaning ( P >0. 05);at the reperfusion time of 1,6 and 24 hours, oncosis and apoptosis is higher in OJ - IR group than in OJ group even at the time of 24 hour, the peak amplitude appear at 6 hour, then oncosis begins to decrease;in OJ - IR group apoptosis raises followed with reperfusion until the time of 24 hour (P<0.05).ConclusionThis experiment aims to study hepatic cell death patterns in obstructive jaundice and reperfusion after obstructive jaundice through obstructive jaundice - hepatic ischemic reperfusion/ biliary tract recanalization rat model, the results manifest that;1. Hepatic cell death pattern of rats with obstructive jaundice is firstly oncosis and secondly apoptosis.2. Hepatic cell death pattern of rats with obstructive jaundice followed with ischemic reperfusion injury depends on oncosis mostly, and at 24 hour the pattern changes into apoptosis.3. Hepatic cell injury in obstructive jaundice followed with ischemic reperfusion has a close relationship with the increase of hepatic cell oncosis after ischemic reperfusion.