The Mechanism And Protection Of Stomach Injury After Total Hepatic Ischemia-reperfusion

Background and Objective:Liver transplantation is the effective treatment of end-stage liver disease.During the operation the blood flow in the inferior vena cava, portal vein and hepatic artery need to be blocked, then lots of inflammatory mediator, oxygen redicals, pour into the distant organs with the blood, which lead to the distant organ injury in different degrees. At the same time the interruption of portal vein blood can increase the pressure of portal vein, which may lead to gastrointestinal tract injury, microcirculation disturbance, mucous membrane edema, hemorrhage, ulcers or necrosis. The most dangerous endotoxemia and displacement of intestinal bacteria may threaten the patients'survival.It has not been fullly clear that the mechanism and protection of stomach injury after total hepatic ischemia-reperfusionhas.We have established the model of total hepatic ischemia-repersusion by surgery to observe the changes of gastric function and structure and measure dynamically the changes of inflammatory reaction in plasma and gastric tissue, H2S/CSE system, CaN signal transduction path in the reperfusion injury.We also use NaHS, FK-506, Spiron and MP to search the effective intervention method.Our study is divided into two parts. Firstly, we explore the possible mechansim of the stomch injury after total hepatic ischemia-repersusion. Secondly, we ascertain the energy metabolism of mitochondria on the stomch injury after total hepatic ischemia-repersusion.Method:We have established the model of total rat liver ischemia-reperfusion by surgery.PartⅠ,184 Wistar rats were divided into 23 groups,8 rats each group:the control group,20min ischemia,2h,4h,6h,12h,24h,48h and 72h after 20min ischemia,.40 min ischemia,6h and 72h after 40min ischemia; Spiron, MP 40min+6h and 40min+72h interventianal group. PartⅡ,80 Wistar rats were divided into 10 groups,8 rats each group:control; ischemia 20min; FK506, Spiron, MP, NaHS control and 20min+6h interventianal group.The H2S,MDA, AngⅡ,ALD,TNF-αin blood; and the activity of CSE,CaN;the content of ICAM-1,NF-κB,CaN and the expression of stomch tissue CaNAβmRNA in tissue are determinded.Optical microscope was used to observe the pathological change of gastric mucous.Lastly, we determined the respiratory control rate(RCR),P/O ratio,membrane potential and Na+/K+ ATPase, Ca2- -ATPase activity of mitochondrion by electron microscope to research the mechanism of stomch and mitochondrion injury after ischemia-reperfusion.Result:The results of the first part were as follows:During the beginning period 2h-6h of hepatic ischemia-reperfusion, the stomach function, such as gastric emptying rate and intestinal motility, reached the worst damage. Pathological change of gastric mucous indicated that the most serious injure occur at 6h after ischemia-reperfusion.All variables were compared with the control group.The levels of TNF-α,MDA, Angll in plasma and ICAM-1,NF-κB,ALD in stomch were significantly increased after ischemia-reperfusion,and reached the peak at about 2-6h (P<0.05). The level of ALD in plasma reached the peak at ischemia 20min then decreased after reperfusion. The content and mRNA of CaN in stomch was increased in ischemia period then down to the valley at 12h after reperfusion, reached baseline at 72h. The activity of CaN didn't change in ischemia period and the beginning of reperfusfion; it increased until reperfusion 6h, and got the peak at 12h after reperfusion. The levels of H2S in plasma increased significantly at 2h after ischemia and reached a peak 6h after reperfusion, then reached baseline 72h. The stomch level of CSE was markedly decreased and reached the lowest at 12h after reperfusion. The trend in the ischemia 40min was the same as the ischemia 20min, but the indexes changed more obviously than the ischemia 20min group, and the pathological examination showed the tissue injury was more severe. After the intervention of the four medicines:FK506, MP, Spiron and NaHS, the injury of the gastric tissue were improved with the varying degrees.The results of the second part were as follows:The activity of the mitochondria enzyme changes, and the RCR,P/O and membrane potential were significantly lower. After the intervention of the four medicines above, the respiratory function and ATPase activity were improved under the varying degrees after total hepatic ischemia reperfusion.Conclution:The total hepatic ischemia and reperfusion can induce the injury of the renmote stomch, the longer stomch ischemia, the more serious injury, and the most serious time point is the 6 hours after ischemia-reperfusion. The mechanism may be involved in the activating of neutrophil and inflammatory cytokines, excess oxidative stress. Down-regulation of endogenous H2S/CSE system and up-regulation of CaN signal transduction also participate in the stomch and mitochondrion injury after total liver ischemia and reperfusion. Exogenous H2S, MP,FK506,Spiron can protect stomch after ischemia-reperfusion.