| Objective: With the development of surgical techniques, the clinical application of University of Wisconsin liquid and all kinds of new immunosuppressive agents, liver transplantation gradually becomes an effective therapy to the patients with final liver disease. But the receptors usually have many complications during perioperative period, and pulmonary dysfunction and failure are the most dangerous complications after operation. Pulmonary complications can generate the chain-reaction of multi-organic and systematic dysfunction and result in donative's liver failure in the end. So protecting the receptors from the emerging of pulmonary complications is very important. Most receptors in China suffered from posthepatitic cirrhosis with portal hypertension and a lot of enlarged portosystemic collaterals. Based on this characteristic, the orthotopic liver transplantation (OLT) without venous bypass, which is simpler and cheaper relatively, is widely adopted in China. The pulmonary ischemia-reperfusion injury (I-R injury) after anhepatic phase is known as the important inducement of pulmonary complications during perioperative period of OLT. In this experiment, the recoverable prehepatic portal hypertensive model rats were made at first, and then the first hepatic portal and the inferior vena cava below the liver were clamped at the same time. After 60 minutes of occlusion, the reperfusion is begun. We aim at imitating the anhepatic phase of clinical OLT and try to find the character and mechanism of pulmonary I/R injury after anhepatic phase. So we can make progress in precaution and treatment of pulmonary complications during perioperative period of OLT. Methods: 135 healthy male Wistar rats, weighted 250-300g,were used.15 rats were taken randomly as normal control group(NC),the recoverable prehepatic portal hypertensive models were generated on the other rats through the first operation which partly narrow portal vein and let the"mark ring"in. Three weeks later, all the model rats generated successfully. 15 model rats were taken randomly as portal hypertensive control group(PHTC), the other 105 model rats were performed the second operation and then were divided into 0h,6h,12h,24h,48h,72h,7d group according to different reperfusion time after the occlusion. Each group contained 15 rats. Free portal pressure and the area of esophageal submucosal veins were measured in NC group and PHTC group. Portovenography were performed in NC group and PHTC group. ALT ,AST ,TBiL level in serum, partial pressure of oxygen in arterial blood, myeloperoxidase(MPO) activity in lung tissue, dry-to-wet weight ratios of lung were measured. Morphology changes of liver and lung were observed by optical microscope and transmission electron microscope. All data of experimentwere analyzed by statistic software of SPSS 11.0. Results: Three weeks later after the first operation, all the portal hypertensive model rats were generated successfully. Ascites and varices of viscera could be seen in the PHTC group, but the color and texture of liver were normal. The free portal pressure of PHTC group was 15.6±3.1mmHg,is obviously higher than that of NC group(7.7 ±1.7mmHg),and the difference was significant(P<0.05).When the"mark ring"was removed, the portal pressure was 13.4±2.3mmHg,which was significantly higher than that of NC group (P<0.05),but there was no obvious difference compared with that of PHTC group (P>0.05).The portovenography of PHTC group showed that development of liver was slow, and a stenosis could be seen at the portal vein trunk proximal to the bifurcation, the vessels of portal system twisted and dilated, the enlarged veins such as left adrenal vein and azygos vein could be seen, the superior and inferior vena cava through the portosystemic shunt developed,the stenosis of portal vein disappeared after removing the "mark ring". There were no shunts between portal and venacaval system in NC rats. The area of esophageal submucosal veins of NC group and PHTC group were 5.620±1.301μm2 and 33.582±6.425μm2 respectively...
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