| Liver transplantation has become the most effective treatment for the end stage of liver diseases. But the incidence rate of primary nonfunction(PNF) after liver transplantation is still high. That is the main cause of death after liver transplantation and has complicated mechanisms. At the same time, the hepatic ischemia and reperfusion injury(IRI) has been thought of the main cause of PNF after liver transplantation. So how to relieve the hepatic IRI has became the hot spot of clinical research. Ischemic preconditioning(IPC) has shown to relieve the hepatic IRI effectively. But its clinical application is very complex because of its short-time ischemia and reperfusion. Adenosine has been proved to be the key point of the effect of IPC. The augmentation of the adenosine can protect the liver against IRI. Dipyridamole(DP) can increase the concentration of endogenous extracellular adenosine as an inhibitor of nucleoside transport. Recently there are many reports about the dipyridamole applied for the liver preconditioning. But most of them are fundamental research and the model of ischemia and reperfusion also differs from the liver transplantation model. Objective: In this study, we built the model of rat orthotopic liver transplantation(OLT) successfully and used different doze of dipyridamole to undertake preconditioning of liver. The level of serum alanine aminotransferase(ALT), aspartate aminotransferase (AST), liver tissue nitric oxide(NO), myeloperoxidase (MPO), Na+-K+-ATPase and Ca2+-ATPase were tested. At the same time we observed the histopathological change of liver. So we can evaluate the effect of dipyridamole preconditioning on IRI of the liver transplantation by the results. We hope it will help us finding the theoretical and experimental basis of dipyridamole preconditioning in protecting the liver against IRI. Methods: Eighty healthy male Wistar rats were divided into four groups randomly,there are twenty rats in every group. Group A is matched control group: we inject them 2ml Saline from dorsal vein of penis 1h before transplantation, then to practise orthotopic liver transplantation. Group B ,C and D are dipyridamole preconditioning groups. We inject them 2ml dipyridamole saline solution(at a dose of 0.2mg/kg ,0.3mg/kg and 0.4mg/kg respectively) from dorsal vein of penis 1h before transplantation, then to practise liver transplantation as group A. We will get 0.2g liver tissue before transplantation (from the donor) and 1h after reperfusion of the portal vein (from recipient before closing abdomen). And put the rat to death 6h after reperfusion of the portal vein and take hepatic lobule. The liver tissue we get above must be preserved at -70℃environment (liquid nitrogen). We shall draw blood about 1.5-2ml from abdominal aorta from the recipient before transplantation and 6h after reperfusion of the portal vein respectively, then get blood serum preserved at -20℃refrigerator. At last, the level of serum alanine aminotransferase(ALT), aspartate aminotransferase(AST), liver tissue nitric oxide(NO),myeloperoxidase(MPO),Na+-K+-ATPase and Ca2+-ATPase were all measured. At the same time, the histopathological changes of liver samples were observed under optical microscope. During the operation cold ischemic time, non-hepatic time and surgical time of recipient were all recorded. Results:(1).Cold ischemic time, non-hepatic time and surgical time of recipient among 4 groups have less discrimimation(P>0.05); (2).The levels of serum ALT and AST at 6h after reperfusion of the portal vein were significantly higher than that of time before transplantation in the same group (P<0.05). Among them group A is the highest. In the identical time, significant decreases were seen in group C and D comparing with group A (P<0.05), and group C is the lowest (P<0.05). (3).The level of NO: The liver tissue NO of group C is significantly higher than other groups (P<0.05). In the time of 1hafter reperfusion the portal vein, the level of NO of all groups decreased significantly compared with that of time before transplantation. In this time spot, Group C and D are significantly higher than group A and B (P<0.05). Group C is higher than group D (P<0.05). Its level still decreases in the time 6h after portal vein's reperfusion, and group C and D are still higher than group A and B, the difference is significant (P<0.05). At the same time, group C is higher than group D (P<0.05) . (4).The level of MPO: Liver tissue MPO has no significant difference among the four groups before transplantation. In the time of 1h after reperfusion of the portal vein, the level of MPO of all groups increased significantly comparing with that of time before transplantation (P<0.05). In the same time spot, group C and D are significantly lower than group A and B (P<0.05). Group C and D have no difference. Its level still increases in the time 6h after reperfusion of the portal vein. In this time spot group C and D are still significantly lower than group A and B (P<0.05). At the same time, group C is lower than group D (P<0.05) . (5).The level of Na+-K+-ATPase and Ca2+-ATPase have no significant difference among the four groups before transplantation. In the time of 1h after reperfusion of the portal vein, their level of all groups decreased significantly comparing with that of time before transplantation (P<0.05). In the same time spot, group C and D are significantly higher than group A and B (P<0.05). Group C is higher significantly than group D (P<0.05). Their level still increase in the time 6h after reperfusion of the portal vein, group C and D are still significantly higher than group A and B (P<0.05). Group C is still higher significantly than group D (P<0.05). (6).the histopathological changes: Before transplantation, the hepatocyte of group A line up in order, the structure of hepatic lobule is normal. After injecting DP intravenously, the capillary of the hepatic lobules dilated and congest obviously. This change is more significant as the dose of DP increase. So group D changes most significantly. When in the time of 6h after reperfusion, in...
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