【Abstract】ObjectiveTo investigate whether heme oxygenase-1 can alleviate the ischemiareperfusion injury of the aged donor liver. MethodsThe activity of superoxide dismutase (SOD) and catalase (CAT), and the contents of tocopherol (Vit E), ascorbic acid (Vit C) and malondialdehyde (MDA) were measured in the livers of adult SD rats (n=5) and aged SD rats (n=5). The experimental aged donor group (n=30) received intraperitoneal injection of Hemin 24 hours before operation, the control aged donor group(n=30) received saline. The histologic changes and apoptosis in the donor liver were observed. ResultsThe activity of SOD and the contents of Vit E and Vit C decreased significantly in 5 aged rats（P＜0.05）, but the content of MDA increased（P＜0.05）. Before the harvesting of the grafts, the activity of SOD and the contents of Vit E and Vit C increased significantly in rats pretreated with Hemin （P＜0.05） and the content of MDA decreased（P＜0.05）. The apoptotic cells in the livers pretreated with Hemin also decreased significantly after reperfusion（P＜0.05）. ConclusionThe liver of aged rat presents oxidative stress and peroxidative state. Ischemia-reperfusion injury can be alleviated by the induction of HO-1.
【Abstract】 Objective To investigate the effect of verapamil on apoptosis, calcium and expressions of bcl-2 and c-myc of pancreatic cells in ischemia-reperfusion rat model. Methods Wistar rats were randomly divided into three groups: control group （n=10）; ischemia-reperfusion group （n=10）; verapamil treatment group （n=10）. The anterior mesenteric artery and the celiac artery of rats in both ischemia-reperfusion group and verapamil treatment group were occluded for 15 min followed by 12-hour reperfusion. Verapamil （1 mg／kg） was injected via caudal vein to the rats in verapamil treatment group 15 min before occlusion and 1 hour after the initiation of reperfusion, respectively; and ischemia-reperfusion group was given the same volume of salient twice intravenously. Pancreatic tissues were collected from the dead rats after twelve hours since the reperfusion. The pathologic characters of pancreatic tissue were observed under light microscope; The level of calcium in the tissue was measured by atomic absorption spectrometer; TUNEL was used to detect apoptosis of pancreatic cells; and the expressions of c-myc and bcl-2 in the cells were also analyzed by immunohistochemistry technique and flow cytometry. Results The pathologic change in verapamil treatment group was less conspicuous than that of ischemia-reperfusion group. Both the calcium level and the number of apoptotic cells in verapamil treatment group were less than those of ischemia-reperfusion group 〔（411.1±55.8） μg/g dry weight vs （470.9±31.9） μg/g dry weight, P＜0.05 and （9.5±2.9）% vs （18.4±3.1）% 〕, P＜0.05. After taking verapamil, the number of apoptotic cells decreased, whereas the expressions of bcl-2 and c-myc increased. The fluorescent indexes of bcl-2 and c-myc in verapamil treatment group were significantly higher than those of ischemia-reperfusion group (1.72±0.11 vs 1.41±0.07, P＜0.05; 1.76±0.19 vs 1.55±0.13, P＜0.05. Conclusion Ischemia-reperfusion injury can induce apoptosis of pancreatic cells. Verapamil could protect the injured pancreatic tissue by reducing the level of calcium, stimulating the expressions of bcl-2 and c-myc and inhibiting apoptosis of pancreatic cells.
Objective To summarize recent research advancement on gene therapy for hepatic ischemia-reperfusion injury (IRI). Methods Relevant references about basic and clinical researches of hepatic IRI were collected and reviewed. Results Recent experimental researches indicated that the expression of several genes and cytokines could protect hepatic cells by suppressing cell apoptosis, decreasing the production of oxyradical, remaining and improving portal venous flow, promoting bilifaction, self immunoloregulation and decreasing inflammatory reaction, so that it could decrease IRI. Conclusion IRI could be decreased by regulating the expressing of target genes or transducing relative genes in vivo, but the path of gene transfer and the selection and optimization of gene carrier still need more basic and clinical researches to prove.
Objective To investigate the maximum tolerance limit of rats to hepatic inflow occlusion with portal vein blood bypss (PBB) in normothermia. Methods First. A new animal model was established, the animal survival rate were calculated following 7 days of reperfusion after hepatic inflow occlusion of 30, 60, 90, 100, 110, 120 min or portal triad clamping (PTC) of 30 min. And then, the hepatic energy metabolism (RCR, P/O, ATP, AKBR) was studied following 30, 90, 120 min of ischemia or 1, 6, and 24 hours of reperfusion after the ischemia. According to the reversibility of the hepatic motochondrial function injury and maximum as long as a period of liver warm ischemia of all animal postoperative 7 days survial, the safe limit of rat to hepatic inflow occlusion was evaluated. Results The survival rate on postoperative 7 days was one hundred percent subjected to 30, 60 and 90 min of hepatic inflow occlusion, and 50, 30, 20 percent in 100, 110, 120 min, respectively, the survival rate in rats with 30 min of portal triad champing was about 40 percent. The parameters of hepatic motochondrial function reflecting the degree of liver damage to ischemia showed significantly different as compared to sham group. The functional lesion was exacerbated during inital reperfusion, then was restored progressively in PBB-30 min and PBB-90 min groups, but was maintained low level in PBB-120 min and PTC-30 min groups.Conclusion The 90 minutes is the maximum limit of rats to hepatic inflow occlusion in normothermia.
Objective To investigate the effects of adenosine 2A receptor (A2AR) activation on oxidative stress in small-forsize liver transplantation. Methods A rat orthotopic liver transplantation model was performed using 40% graft, 18 recipients were given intravenously saline (control group), CGS21680 (A2AR agonist, CGS21680 group) or ZM241385 (A2AR antagonist, CGS21680+ZM241385 group) randomly. Aspartate aminotransferase (AST), enzymatic antioxidants 〔superoxide dismutase (SOD); catalase (CAT); glutathione peroxidase (GSH-Px)〕, non-enzymatic antioxidants 〔ascorbic acid (AA); glutathione (GSH); α-tocopherol (TOC)〕 and lipid oxidant metabolites malondialdehyde (MDA) were measured and analyzed at 6 h after reperfusion. Results Compared with the control group and CGS21680+ZM241385 group, A2AR activation increased the activities of SOD and GSHPx (Plt;0.05), reduced the productions of AST and MDA (Plt;0.05), increased the levels of AA, GSH and TOC (Plt;0.05) in CGS21680 group. But there was no significant change in CAT activity (Pgt;0.05) among 3 groups. Conclusions A2AR activation improves the antioxidant enzyme activities, promotes the production of antioxidants, and slowes down the increase in MDA level, depresses of the increase in AST activity. A2AR activation suppresses oxidative damage and increases the antioxidant capacity which in turn minimizes their harmful effects of ischemia-reperfusion in small-for-size liver transplantation.
【Abstract】ObjectiveTo investigate the effect of ischemia-reperfusion （I/R） injury on apoptosis of pancreatic cells in rats with acute pancreatitis(AP). MethodsFifty-four SD rats were randomized into 3 groups: pancreatitis group (n=24), I/R-injury group (n=24) and control group (n=6). The animal model of AP was induced by retrograde injection of 3% sodium taurocholate into biliopancreatic duct in rats. Pancreatic I/R was caused by blocking the inferior splenic artery and removing the clamp after AP induction. At 1 h, 3 h, 6 h and 12 h, groups of rats were sacrificed. A terminal deoxynucleotidyl transferase-mediated dUTP-biotion nick end labeling (TUNEL) was used to detect pancreatic apoptosis, and histological changes of the pancreas were observed. ResultsPancreatic hemorrhage, necrosis were respectively observed in the pancreatitis rats at 6 h and the I/R-injury rats at 1 h. Histological changes of the pancreatitis rats at 1 h and 3 h were only congestion and edema. Apoptoic acinar cells increased after AP induction, the peak respectively appeared at 6 h in the pancreatitis rats and at 3 h in the I/R-injury rats. Compared with the pancreatitis rats, apoptosis index (AI) of the I/Rinjury rats was significantly higher at 1 h and 3 h (P＜0.01, P＜0.05, respectively), but lower at 6 h and 12 h (P＜0.05, P＜0.01, respectively). ConclusionI/R injury can induce conversion of edematous pancreatitis to hemorrhagic necrotizing pancreatitis and apoptosis of acinar cells. Apoptosis may be a beneficial response to pancreatic injury in AP.
Objective To investigate the research base and current understanding of the mechanism of ischemia-reperfusion injury (IR) to intrahepatic cholangiocytes after l iver transplantation, so as to identify the key points of the mechanism and provide references for cl inical practice. Methods We searched PubMed (1970 to 2007) and CBM(1979 to 2007). Qual ity assessment and data collection were performed by two reviewers independently. Since the baseline supplied and the measure were very different, we decided to provide a descriptive summary only. Results The earliest study on liver IR was publ ished in 1970. A total of 65 papers were included. There were 13 on cl inical studies, 35 on basic research studies; and 17 review articles. Most basic studies focus on injury mechanism: ① The physiology of bile ducts and Intrahepatic Bil iary Duct Cells(IBDC); ②the IR caused injury mechanism of IBDC during or after liver transplantation; ③ the basic injury mechanisms include: cold ischemia, warm ischemia, reperfusion, injury of bile and bile salts. Most clinical studies focused on preventive measures, including surgical and non-surgical approaches. Based on the evidence from basic research, changing the composition and perfusion methods of perfusate and protecting the specific blood supply to biliary ducts and cholangiocytes during the operation were important in preventing or reducing such an injury. Conclusion ① The heterogeneity of morphology, function, status and the special blood supply in large and small IBDC are important material base. ② Our own study indicated that simple IR or H/R was able to change the expression of MHC, MIC, DR4, DR5 and other adhesion molecules. ③ Compared to hepatic cells, hIBDC can’ t resist cold ischemia and even worse in tolerating reperfusion injury. ④ Hydrophobic bile salts will could increase the harm to bile ducts during organ preservation. ⑤ Due to the low quantity and limited quantities of clinical researches, the power of evidence was low. The evaluation indexes and baseline conditions are not unified. So the conclusions are for reference only.
【Abstract】 Objective To study the effects of ischemic preconditioning (IP) on the activity of nuclear factor-κB （NF-κB） and the expressions of TNF-α and intercellular adhesion molecule-1 (ICAM-1) during early reperfusion following liver transplantation in rats. Methods The models of rat orthotopic liver transplantation were established. The donor livers were stored for 2 hours in Ringers solution at 4 ℃ before transplantation. All rats were randomly divided into sham operation group （SO group）， control group and IP group. IP group was achieved by clamping the portal vein and hepatic artery of donor liver for 10 minutes followed by reperfusion for 10 minutes before harvesting. The activity of NF-κB and expressions of TNF-α and ICAM-1 at 1 h, 2 h, 4 h and 6 h after reperfusion were measured. Serum ALT, LDH were also determined. Results The liver function of recipients with IP were significantly improved. Compared with SO group， the graft NF-κB activity increased after transplantation in control group and IP group (P＜0.05), while compared with control group that was significantly attenuated at 1 h and 2 h in IP group. Similarly, hepatic levels of TNF-α and ICAM-1 were significantly elevated in control group and were reduced in IP group. Conclusion IP might down-regulated TNF-α and ICAM-1 expression in the grafts after orthotopic liver transplantation through depressed NF-κB activation， and attenuate neutrophil infiltration in the grafts after reperfusion.
Objective To observe the influences of depolarized arrest and hyperpolarized arrest on alternation of fluidity of myocardial cell membrane during cardiopulmonary bypass (CPB) and evaluate the protective effects on myocardium of hyperpolarized arrest. Methods Seventy-two felines were randomized into three groups, each group 24. Control group: 180 minutes of CPB was conducted without aortic and vena caval cross-clamping. Depolarized arrest group: hearts underwent 60 minutes of global ischemia after aortic cross-clamping (ACC) followed by 90 minutes of reperfusion. The cardioplegic solution consisted of St. Thomas solution (K+16mmol/L). Hyperpolarized arrest group: the protocol was the same as that in depolarized arrest group except that the cardioplegic solution consisted of St.Thomas solution with pinacidil (50 mmol/L,K+5mmol/L). Microviscosity, the reciprocal of fluidity of myocardial membrane was measured in all groups by using fluorescence polarization technique. (Results )Microvis cosity of myocardial cell in depolarized arrest group during ACC period was significantly higher than that before ACC and kept on rising during reperfusion period. Microviscosity of myocardial cell in hyperpolarized arrest group during ACC was trending up and reperfusion periods as well, but markedly lower compared to that in depolarized arrest group at corresponding time points(Plt;0.01). Conclusion Hyperpolarized arrest is more effective in protecting myocardial cells from ischemia-reperfusion injury than depolarized arrest during CPB by maintaining better fluidity of myocardial membrane.
Objective To study the effect of dexamethasone to protect flaps from an ischemia-reperfusion injury and elucidate its mechanism of regulating the death course of the neutrophils.Methods The rats were randomly divided into 3 groups.The vein of the rat was clamped for 8 h after the flap had formed. Group A: the normal flap; Group B: the saline control flap; Group C: the treatment flap with dexamethasone. The survival area of the flaps was measured at 7 days; the apoptotic and necrotic neutrophils,tumor necrosis factor α （TNF-α）, and interleukin 10 （IL-10） concentrations were measured. Results The flap survival areas in Groups A and C were larger than those in Group B. The apoptotic neutrophils in Group B were fewer than those in Groups A and C on the 1st and 3rd days after operation; however, they were more in number in Group B than in groups A andC on the 6th day. The necrotic cells in Group B were more in number than those in Groups A and C. In Group B, the plasma TNF-α concentration reached the maximum level at 1 h,while the IL-10 level reached the lowest 3 h after the reperfusion. In Group C, the TNF-α concentration was lower than that in Group B and decreased dramatically at 6 h. The IL-10 concentration was the lowest at 1 h, and increased rapidly at 3 h. Thus, ischemia reperfusion could injure the flaps, probably through the abnormal action of the neutrophils, such as the disordered secretion of the cytokines and abnormal death course of the neutrophils. Conclusion Dexamethasone can protect the flap from an ischemia-reperfusion injury by its regulation for the neutrophil function.