Lysoplasmenylethanolamine accumulation in ischemic/reperfused isolated fatty acid-perfused hearts.

Lysophospholipid accumulation has been implicated in the pathogenesis of irreversible injury during myocardial ischemia and reperfusion. Plasmalogens (phospholipids with a vinyl-ether bond in the sn-1 position) account for more than 50% of total myocardial sarcolemmal and sarcoplasmic reticulum phospholipids. Accumulation of plasmalogen choline and ethanolamine lysophospholipids (lysoplasmenylcholine and lysoplasmenylethanolamine) or the effects of exogenous fatty acids on lysoplasmalogen accumulation during ischemia and reperfusion have not been examined. Isolated working rat hearts perfused with buffer containing either 11 mM glucose or 11 mM glucose plus 1.2 mM palmitate were subjected to aerobic, ischemic, or ischemia/reperfusion protocols. Levels of lysoplasmenylcholine and lysoplasmenylethanolamine were quantified using a two-stage high-performance liquid chromatographic technique. In hearts perfused with glucose alone, no significant differences in levels of lysoplasmenylcholine or lysoplasmenylethanolamine were seen during ischemia or reperfusion. In fatty acid-perfused hearts, however, significant accumulation of lysoplasmenylethanolamine occurred during reperfusion but not during ischemia (723 +/- 112, 734 +/- 83, and 1,394 +/- 193 nmol/g dry wt for aerobic, ischemic, and ischemic/reperfused hearts, respectively; p less than 0.05 for ischemic/reperfused hearts versus aerobic or ischemic hearts). Lysoplasmenylcholine levels after ischemia and reperfusion did not differ significantly from aerobic values, regardless of whether fatty acids were present or absent from the perfusate. Aerobic and ischemic/reperfused rabbit hearts, in the presence of fatty acid, showed a similar profile in their lysoplasmalogen content. We conclude that differential lysoplasmenylethanolamine accumulation occurs during myocardial reperfusion when exogenous fatty acid concentrations are high. This may reflect the selective action of fatty acid intermediates on the metabolism of lysoplasmenylethanolamines.(ABSTRACT TRUNCATED AT 250 WORDS)     

Protective role of an endothelin-converting enzyme inhibitor (FR901533) in hepatic ischemia/reperfusion injury.

INTRODUCTION: There is evidence that endothelin (ET) contributes to disturbances of the hepatic microcirculation after warm ischemia/reperfusion (I/R) by causing vasoconstriction and by enhancing leukocyte endothelium interactions. The aim of this study was to investigate a possible protective role of the endothelin converting enzyme (ECE) inhibitor FR901533 in this setting. METHODS: In an in vivo model (42 Wistar rats), hepatic ischemia was induced for 30 min by Pringle's maneuver. Sham operated (I), untreated ischemic (II), and treatment (III) groups with FR901533 (1 mg/kg bw iv) were investigated. The effect of FR901533 in I/R was assessed by in vivo microscopy (30-90 min after reperfusion), measurement of local tissue pO2 (30 and 60 min after reperfusion), and determination of AST/ALT levels (2 h, 6 h, and 2, 6, and 14 days after reperfusion). RESULTS: In the untreated ischemic group (II) sinusoidal constriction to 76.3 +/- 4.2% of basic diameters was observed, leading to significant decreases in perfusion rate (82.3 +/- 3.6% of sham group) and in liver tissue pO(2) (43.5 +/- 3.2% of sham group) (P < 0.05). In addition, we found an increased percentage of stagnant leukocytes in sinusoids (138.3 +/- 9.8) and sticking leukocytes in postsinusoidal venules (155.2 +/- 3.3% of sham group) (P < 0.05). Hepatocellular damage (AST/ALT increase to 430.6 +/- 47.7 U/L/200.2 +/- 23.8 U/L, pre: 27.4 +/- 2.7 U/L/28.1 +/- 2.7 U/L) was detected 6 h after reperfusion (P < 0.05). Administration of the ECE inhibitor before ischemia significantly reduced I/R injury. Sinusoidal diameters were maintained (102.2 +/- 1.7%), while perfusion rate (93.1 +/- 1.8%) and tissue pO2 (105.3 +/- 2.7%) increased significantly (P < 0.05). Hepatocellular damage was decreased (AST/ALT levels after 6 h of reperfusion: 166.6 +/- 26.3 U/L/132.4 +/- 22.5 U/L, P < 0.05) and leukocyte sticking and rolling were significantly reduced (P < 0.05). CONCLUSION: Our results provide evidence that the new therapeutic approach with an ECE inhibitor is effective in reducing hepatic I/R injury.     

Glucose and palmitate oxidation in isolated working rat hearts reperfused after a period of transient global ischemia

Alterations in energy substrate utilization during reperfusion of ischemic hearts can influence the functional recovery of the myocardium. Energy substrate preference by the reperfused myocardium, however, has received limited attention. Therefore, we measured oxidation rates of glucose and palmitate during reperfusion of ischemic hearts. Isolated working rat hearts were perfused with 1.2 mM palmitate and 11 mM [14C]glucose, 1.2 mM [14C]palmitate and 11 mM glucose, or 11 mM [14C]glucose alone, at an 11.5 mm Hg preload and 80 mm Hg afterload. Hearts were subjected to 60-minute aerobic perfusion or 25-minute global ischemia followed by 60-minute aerobic reperfusion. Steady-state oxidative rates of glucose or palmitate were determined by measuring 14CO2 production. In hearts perfused with glucose alone, oxidative rates during reperfusion were not significantly different than nonischemic hearts (1,008 +/- 335 vs. 1,372 +/- 117 nmol [14C]glucose oxidized/min/g dry wt, respectively). In the presence of palmitate, glucose oxidation was markedly reduced in reperfused and nonischemic hearts (81 +/- 11 and 101 +/- 15 nmol [14C]glucose oxidized/min/g dry wt, respectively). Palmitate oxidation rates were not significantly different in reperfused compared with nonischemic hearts (369 +/- 55 and 455 +/- 50 nmol [14C]palmitate oxidized/min/g dry wt, respectively). [14C]Palmitate was incorporated into myocardial triglycerides to a greater extent in reperfused ischemic hearts than in nonischemic hearts (26.0 and 13.8 mumol/g dry wt, respectively). Under the perfusion conditions used, palmitate provided over 90% of the ATP produced from exogenous substrates. Addition of the carnitine palmitoyltransferase I inhibitor, ethyl 2-[6-(4-chlorophenoxy)hexyl]oxirane-2-carboxylate (Etomoxir, 10(-6) M), during reperfusion stimulated glucose oxidation and improved mechanical recovery of ischemic hearts.(ABSTRACT TRUNCATED AT 250 WORDS)     

库普弗细胞Toll样受体2在小鼠肝脏缺血再灌注损伤中的表达及意义

目的探索库普弗细胞Toll样受体2(TLR2)在肝脏缺血再灌注损伤中的表达变化,分析库普弗细胞TLR2信号通路参与肝脏缺血再灌注损伤的机制。方法动物分假手术对照(SH)组、缺血再灌注(I/R)组及氯化钆处理(Gd)组,复制小鼠肝脏部分缺血1 h再灌注4 h损伤模型,结束再灌注后,取缺血叶肝脏组织及其库普弗细胞,提取总RNA及膜蛋白质分析TLR 2 mRNA及蛋白的表达,同时提取缺血肝叶组织核蛋白分析核因子(NF—κB),并检测门静脉血中肿瘤坏死因子(TNF α)、丙氨酸氨基转移酶(ALT) 及内毒素水平。结果再灌注4 h,(1)I/R组缺血肝叶TLR2 mRNA及蛋白表达水平较SH组高,△Ct值分别为1.06±0.91和5.08±1.32,t=7.80,P<0.01;A值分别为433.91±25.53和102.86±13.58,t=28.04, P<0.01。Gd组缺血肝叶TLR2 mRNA及蛋白表达水平较I/R组下降,△Ct值分别为4.22±0.84和1.06±0.91,t=7.56,P<0.01;A值分别为125.89±15.49和433.91±25.53,t=25.27,P<0.01。(2)I/R组缺血肝叶库普弗细胞中TLR2 mRNA及蛋白表达水平较SH组高,△Ct值分别为0.52±0.23和2.61±0.1 8, t=17.47,P<0.01;A值分别为379.70±34.16和114.98±21.90,t=15.98,P<0.01。Gd组缺血肝叶库普弗细胞中TLR2 mRNA及蛋白表达水平则较I/R组下降,△Ct值分别为1.90±0.14和0.52±0.23,t= 12.     

Toll样受体参与小鼠肝脏缺血再灌注损伤

目的探讨Toll样受体是否参与小鼠肝脏缺血再灌注损伤及其机制. 方法用Toll样受体缺损小鼠(C3H/Hej,Hej组)和野生型(C3H/Heouj,Heouj组)小鼠复制部分肝脏缺血再灌注损伤模型,于缺血45min,再灌注1h和3h处死动物,检测血清天门冬氨酸氨基转移酶(AST)和血清肿瘤坏死因子α(TNFα)的含量;并以northern blot及髓过氧化物酶(MPO)试验分别检测缺血肝组织TNFα mRNA的表达和MPO的含量. 结果 (1)再灌注1、3h,与假手术组相比,小鼠血浆AST明显升高,但Hej组明显低于Heouj组(661.83U/L±106.09U/L和1215.5U/L±174.03U/L,t＝-6.65,P<0.01;1145.17U/L±132.43U/L和2958.17U/L±186.81U/L,t＝-5.57,P<0.01);(2)再灌注3h时,与假手术组相比,Hej组和Heouj组小鼠血清TNFα浓度明显升高,且前者明显低于后者(152.39pg/ml±43.3pg/ml和249.12pg/ml±51.89pg/ml,t＝-3.13,P<0.05);(3)再灌注1h,除假手术组外,Hej组和Heouj组小鼠缺血肝组织内可见TNFα mRNA的表达,但前者的表达水平明显低于后者,杂交带密度分析显示两者之间差异有显著性 (80.3±28.8与189.4±24.6,t＝-3.25,P<0.05);(4)再灌注3h,与假手术组相比,Hej组和Heouj组小鼠缺血肝组织内MPO含量明显升高,且前者含量明显低于后者(0.059±0.004和0.173±0.025,F＝33.49,P<0.01). 结论 Toll样受体可能通过其介导的炎性通路参与了小鼠肝脏缺血再灌注损伤.     

Protective effect of N2-mercaptopropionylglycine on rats and dogs liver during ischemia/reperfusion process

BACKGROUND: N2-mercaptopropionylglycine is a powerful super oxide synthesis inhibitor and has been tested as a preventive agent of metabolic and structural hepatic damage in the ischemia/reperfusion process. AIM: To analyze some effects of N2-mercaptopropionylglycine administration to animals of two species submitted to normothermic liver ischemia/reperfusion. MATERIAL AND METHODS: Twenty-two rats and 22 dogs were divided into four groups: group I: rats that received intravenous saline 0.9%; group II: rats that received 100 mg/kg of N2-mercaptopropionylglycine; group III: dogs that received saline intravenous 0.9% and group IV: dogs that received 100 mg/kg N2-mercaptopropionylglycine. RESULTS: Ten minutes after the saline or drug administration, each group was submitted to left lobe liver ischemia for 25 minutes followed by reperfusion. Biochemical studies 24 hours after reperfusion revealed a significantly lower elevation of transaminases in animals of groups II (AST = 271 +/- 182; ALT = 261 +/- 161 ) and IV (AST = 101 +/- 45; ALT = 123 +/- 89) when compared to the controls group: I (AST = 2144 +/- 966; ALT = 1869 +/- 1040 00) and III (AST = 182 +/- 76.51; ALT = 277 +/- 219), respectively. Histology study demonstrated a significantly minor aggression to animals of groups II and IV when compared to groups I and III, respectively. CONCLUSION: These results suggest a significant release of free radicals of oxygen in the process and that N2-mercaptopropionylglycine may have a significant protective effect on liver parenchyma when submitted to ischemia/reperfusion.     

Effects of Wy14643 on hepatic ischemia reperfusion injury in rats

AIM： To investigate the effects and possible mechanisms of Wy14643 on hepatic ischemiareperfusion （I/R） injury in rats. METHODS： Thirty male Sprague-Dawley rats weighing 220-280 g were randomly divided into five experimental groups： sham group （G1, n = 6）： a sham operation was performed （except for liver I/R）, I/R-untreated group （G2, n = 6）： rats underwent liver ischemia for 90 min followed by reperfusion for 4h; and I/R ＋ Wy14643 groups （G3, G4, G5; n = 6）： after the same surgical procedure as in group 2, animals were pretreated with Wy14643 at the dose of 1, 5 and 10 mg/kg 1 h before ischemia, respectively. Hepatic ischemia-reperfusion （I/R） was induced by clamping blood supply to the left lateral and median lobes of the liver for 90 min, and atraumatic clamp was removed for 4 h reperfusion. Blood samples and liver tissues were obtained at the end of reperfusion to assess serum and hepatic tissue homogenate aminotransferase （ALT）, aspartate aminotransferase （AST）, myeloperoxidase （MPO）, serum interleukin- 1β（IL-1β） and tumor necrosis factor alpha （TNF-α）, as well as activity of superoxide dismutase （SOD） and content of malondialdehyde （MDA） in the hepatic tissue homogenate. RESULTS： Hepatic I/R induced a significant increase in the serum levels of ALT, AST, TNF-α, IL-1β and MPO, as well as the levels of ALT, AST and MDA in the liver tissue homogenate, which were reduced by pretreatment with Wy14643 at the dose of 1, 5 and 10 mg/kg, respectively. The activity of SOD in the liver tissue homogenate was decreased after hepatic I/R, which was enhanced by Wy14643 pretreatment. In addition, serum and liver tissue homogenate ALT and AST in the Wy14643 10 mg/kg group were lower than in the Wy14643 1 mg/kg and 5 mg/kg groups, respectively. CONCLUSION： Wy14643 pretreatment exerts significant protection against hepatic I/R injury in rats. The protective effects are possibly associated with enhancement of anti-oxidant and inhibition inflammation res     

Protective effects of tumor necrosis factor antibody and ulinastatin on liver ischemic reperfusion in rats

AIM: To study the protective effects of tumor necrosis factor α(TNFα) antibody and ulinastatin on liver ischemic reperfusion in rats.METHODS: One hundred and twenty male SD rats were randomly divided into four groups: normal control group,ischemic group, TNFα antibody group and TNFα antibody + ulinastatin group. The animals were killed at 0, 3, 6, 9,12 h after ischemia for 60 min and followed by reperfusion.Serum alanine aminotransferase (ALT), malondialdehyde (MDA) and liver histopathology were observed.RESULTS: After ischemic reperfusion, the serum ALT and MDA were remarkably increased, and the hepatic congestion was obvious. Treatment of TNFα antibody and ulinastatin could significantly decrease serum ALT and MDA levels,and relieve hepatic congestion.CONCLUSION: Ulinastatin and TNFα antibody can suppress the inflammatory reaction induced by hepatic ischemic reperfusion, and have protective effects on rat hepatic ischemic reperfusion injury.     

Protective effects of tumor necrosis factor α antibody and ulinastatin on liver ischemic reperfusion in rats

AIM: To study the protective effects of tumor necrosis factor α (TNFα) antibody and ulinastatin on liver ischemic reperfusion in rats.METHODS: One hundred and twenty male SD rats were randomly divided into four groups: normal control group, ischemic group, TNFα antibody group and TNFα antibody + ulinastatin group. The animals were killed at 0, 3, 6, 9, 12 h after ischemia for 60 min and followed by reperfusion. Serum alanine aminotransferase (ALT), malondialdehyde (MDA) and liver histopathology were observed.RESULTS: After ischemic reperfusion, the serum ALT and MDA were remarkably increased, and the hepatic congestion was obvious. Treatment of TNFα antibody and ulinastatin could significantly decrease serum ALT and MDA levels, and relieve hepatic congestion.CONCLUSION: Ulinastatin and TNFα antibody can suppress the inflammatory reaction induced by hepatic ischemic reperfusion, and have protective effects on rat hepatic ischemic reperfusion injury.     

Gadolinium chloride and salvia miltiorrhiza compound ameliorate reperfusion injury in hepatocellular mitochondria

AIM: To investigate the effect of gadolinium chloride (GaCl3)and salvia miltiorrhiza compound (SMCo) on ischemia and reperfusion (I/R) injury in hepatocellular mitochondria.METHODS: Wistar rats were randomly to divided into control group, GaCl3 group, SMCo group and GaCl3 + SMCo group (n=15 each). GaCl3 (7 rmg@kg-1) was injected into tail vein on d 1 and d 2 in contrast group. SMCo ( 2 ml@kg-1) was injected into muscle on d 1 and d 2 in SMCo group. GaCl3+SMCo group received both GaCl3 (iv) and SMCo (im) injection. Control group received saline injection only. On d 3, all the rats were subjected to 2 h ischemia in the middle and left lobes of the liver, followed by reperfusion for 2 h, 6 h and 18 h respectively. The level of serum alanine aminotransferase (ALT) and malondialdehyde (MDA) in hepatocellular mitochondria was measured. Pathological changes in hepatic tissue and in hepatocellular mitochondria were determined with optical microscope and electronic microscope, respectively.RESULTS: Remarkablly pathohistological and biochemical changes were detected after 6 h of I/R. Compared with control, the level of ALT was decreased in GaCl3, SMCo and GaCl3+SMCo treated groups (1 314.0±278.7 vs809.4±196.1,716.6±242.8 and 837.2±190.6 IU@L-1, respectively. P＜0.05).Similarly, the level of MDA was decreased in GaCl3, SMCo and GaCl3+SMCo treated groups (293.1±±51.1 vs 190.8±55.5,214.3±32.9 and 221.0±47.3 nmol@g-1, respectively, P＜0.05).Accordingly, in control group, swelling, degeneration, focal necrosis, infilt-ation of leucocyte were found in reperfused tissue under an optical microscope, and mitochondda swelling, rupture and even breakdown were seen under an electronic microscope.These pathohistological and ultrastructural damages caused by I/R were greatly attenuated in GaCl3, SMCo and GaCl3+SMCo treated groups. However, there was no additive effect observed when GaCl3 and SMCo were used together.CONCLUSION: Both GaCl3 and SMCo can alleviate the I/Rinjury in hepatocellular mitochondria.     

Oxidant stress during reperfusion of ischemic liver: no evidence for a role of xanthine oxidase

Oxygen-derived free radicals might play a role in the injury produced by reperfusion of ischemic organs. Since the generation of reactive oxygen species results in an increased formation of glutathione disulfide, we have attempted to document an oxidant stress during reperfusion of ischemic liver by following the hepatic production of glutathione disulfide in vivo and in the perfused rat liver. Following partial hepatic ischemia of 120 min duration, the plasma concentration of glutathione disulfide gradually increased from 0.8 +/- 0.1 to 9.1 +/- 1.6 microM (mean +/- S.E., n = 6) after 1 hr of reperfusion. The plasma concentration of reduced glutathione increased only 2-fold from 21.4 +/- 2.4 to 38.1 +/- 3.4 microM. The rise in plasma glutathione disulfide was higher with increasing duration of ischemia from 30 to 120 min and was associated with a gradual increase in hepatic glutathione disulfide. The hepatic origin of glutathione disulfide was documented in the perfused rat liver where the release of glutathione disulfide increased gradually during reperfusion following 90 min of warm ischemia from 1.0 +/- 0.1 to 2.6 +/- 0.5 nmole per min per gm liver at 30 min after onset of reperfusion. The administration of allopurinol, an inhibitor of xanthine oxidase, did not decrease the release of glutathione disulfide (29.9 +/- 3.8 nmoles per gm in controls vs. 44.7 +/- 10.0 nmoles per gm in 30 min with allopurinol) and ALT (3.3 +/- 1.4 units per gm in controls vs. 2.6 +/- 0.8 units per gm in 30 min with allopurinol). Our studies document an oxidant stress associated with reperfusion of ischemic liver.(ABSTRACT TRUNCATED AT 250 WORDS)     

Modulation of liver oxidant-antioxidant system by ischemic preconditioning during ischemia／reperfusion injury in rats

AIM: To investigate effects of ischemic pre-conditioning on the liver endogenous oxidant-antioxidant system during ischemia/reperfusion injury. METHODS: Twenty-four male Sprague-Dawley rats were randomly divided into sham-operated (Sham), ischemia/ reperfusion (I/R), ischemic pre-conditioning plus ischemia/ reperfusion (IPC) groups. Serum ALT, AST and hyaluronic acid levels were assayed and pathologic alterations observed. Liver malondialdehyde (MDA) contents, endogenous antioxidant enzymes, superoxidase dismutase (SOD), catalase (CAT), gultathionine peroxidase (GSH-Px) activities, neutrophils accumulation marker, myeloperoxidase (MPO) activities were measured respectively. RESULTS: Compared with I/R group, sinusoidal endothelial cells as well as hepatocytes damages, as assessed biochemically and histochemically, were improved significantly in IPC group; neutrophils infiltration was also markedly reduced. In IPC group, liver peroxidation, as measured by MDA contents, was significantly decreased when compared with I/R group; endogenous antioxidant enzymes, SOD, CAT and GSH-Px activities were markedly higher than that in I/R group. CONCLUSION: Ischemic pre-conditioning exerts protective effects on both hepatic sinusoidal endothelial cells and hepatocytes during liver I/R injury. Its mechanisms may involve dimunition of neutrophils infiltration and modulation of the imbalance of endogenous oxidant-antioxidant system in the organism.     

Effect of MG132 on proteasome activity and prooxidant/antioxidant status of rat liver subjected to ischemia/reperfusion injury.

Aim: Previous studies have shown that proteasome inhibitors exerted protective effects against ischemia/reperfusion injury (IRI) of brain, heart, kidney and intestine. The aim of the present study was to investigate: (i) whether the proteasome inhibitor MG132 protects rat liver against IRI; and (ii) whether MG132 modulates prooxidant/antioxidant status of rat liver subjected to warm IRI. Methods: The left lateral and medial lobes (approximately 70% of the total liver volume) of livers of male Wistar rats were subjected to 30-min ischemia followed by 60-min reperfusion. Lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels were measured in the plasma. Proteasome chymotryptic-like (ChT-L) activity, levels of thiobarbituric acid-reactive substances (TBARS), protein carbonyls (PC) and glutathione (GSH), as well as superoxidase dismutase (SOD), catalase (CAT), glutathionine peroxidase and glutathionine reductase activities were measured in liver fractions. Results: Thirty-min ischemia followed by 60-min reperfusion increased liver TBARS and PC, CAT and SOD activities, but decreased GSH level. Ischemia/reperfusion-induced oxidative stress was exacerbated in mitochondria, indicating that these organelles are the preferential target of IRI. Plasma LDH and AST levels were decreased by MG132 during both ischemia and reperfusion, while ALT values were decreased only after 30 min of reperfusion. MG132 did not significantly affect liver TBARS and GSH levels, but it increased PC and decreased ChT-L activity; the activities of CAT and SOD were also decreased. Conclusions: MG132 exerts a protective effect during the early phase of reperfusion and it modulates prooxidant/antioxidant status of rat liver subjected to warm IRI.     

Steatotic livers are susceptible to normothermic ischemia-reperfusion injury from mitochondrial Complex-I dysfunction

AIM: To assess the effects of ischemic preconditioning (IPC, 10-min ischemia/10-min reperfusion) on steatotic liver mitochondrial function after normothermic ischemia-reperfusion injury (IRI). METHODS: Sixty male Sprague-Dawley rats were fed 8-wk with either control chow or high-fat/high-sucrose diet inducing > 60% mixed steatosis. Three groups (n = 10/group) for each dietary state were tested: (1) the IRI group underwent 60 min partial hepatic ischemia and 4 h reperfusion; (2) the IPC group underwent IPC prior to same standard IRI; and (3) sham underwent the same surgery without IRI or IPC. Hepatic mitochondrial function was analyzed by oxygraphs. Mitochondrial Complex-I, Complex-II enzyme activity, serum alanine aminotransferase (ALT), and histological injury were measured. RESULTS: Steatotic-IRI livers had a greater increase in ALT (2476 ± 166 vs 1457 ± 103 IU/L, P < 0.01) and histological injury following IRI compared to the lean liver group. Steatotic-IRI demonstrated lower Complex-I activity at baseline [78.4 ± 2.5 vs 116.4 ± 6.0 nmol/(min.mg protein), P < 0.001] and following IRI [28.0 ± 6.2 vs 104.3 ± 12.6 nmol/(min.mg protein), P < 0.001]. Steatotic-IRI also demonstrated impaired Complex-I function post-IRI compared to the lean liver IRI group. Complex-II activity was unaffected by hepatic steatosis or IRI. Lean liver mitochondrial function was unchanged following IRI. IPC normalized ALT and histological injury in steatotic livers but had no effect on overall steatotic liver mitochondrial function or individual mitochondrial complex enzyme activities. CONCLUSION: Warm IRI impairs steatotic liver Complex-I activity and function. The protective effects of IPC in steatotic livers may not be mediated through mitochondria.     

大白兔肝缺血再灌注损伤时血浆内毒素的变化及对肝肾功能的影响

目的探讨肝缺血再灌注损伤过程中,肠源性内毒素的动态变化和继发性肝肾功能损害。方法取27只健康成年新西兰大白兔,体重1.4~2.3?,随机分为对照组7只,另外20只作为实验组。以缺血10min(I10min)、缺血20min(I20min)、缺血30min(I30min)和分别再灌注30min(R30min)随机分为3组。对照组取门、腔静脉血测肝肾功能及血浆内毒素,实验组阻断第一肝门造成不同的缺血时段,松开血管夹再灌注30min,其余实验同对照组。结果实验组中血浆谷草转氨酶、谷丙转氨酶、尿素氮、肌苷含量及内毒素浓度均有升高,在I10min/R30min组即有升高,但与对照组相比差异无显著性(P>0.05);而后随着缺血时间的延长这些指标继续明显升高,至I30min/R30min组达最高值,与对照组比差异有显著性(P<0.05~0.01)。肾组织电镜观察发现I10min/R30min组肾脏超微结构无明显改变,而I20min/R30min组和I30min/R30min组肾脏超微结构损害明显。结论肝门阻断后门静脉系统淤血,致肠源性内毒素产生和移位;肝门再开放造成肝缺血再灌注损伤,且随着缺血时间的延长,门、腔静脉血中内毒素水平进行性升高,肝功能进一步损害,最终引起肝肾综合征。     

Oxygen free radical scavengers and reperfusion injury in dog lung preserved in cold ischemia.

Oxygen-derived free radicals are now considered important contributors to tissue injury associated with ischemia and reperfusion. The purpose of this study was to determine the influence of oxygen free radical scavengers on reperfusion injury. The left lower lobes of 15 canine lungs were isolated, preserved, and then reperfused for 120 minutes. Three groups of lobes were studied: Group 1 (n = 5), without ischemia, group 2 (n = 5) four hours of cold ischemia in Euro-Collins solution, group 3 (n = 5) four hours cold ischemia+oxygen free radical scavenger glutathione (0.1 nmol/L) given at the moment of perfusion. Extravascular lung water (grams per gram of blood-free dry lobe weight) after reperfusion was 2.82 +/- 0.32, 5.06 +/- 0.45, 4.21 +/- 0.33 for groups 1 through 3 respectively (p less than 0.001 group 1 versus group 2, p less than 0.001 group 2 versus group 3). Lung tissue lipid peroxidation, measured as thiobarbituric acid reactive material was 125 +/- 11, 270 +/- 30, and 185 +/- 17 nmol/g dry lobe weight for groups 1, 2 and 3 respectively (p less than 0.05 group 2 versus 1 and group 3 versus group 2). The data suggest that oxygen free radical scavengers attenuate reperfusion injury.     

NF-kB在大鼠肝缺血再灌注损伤中的活化及意义

目的探讨NFkB在肝缺血再灌注损伤过程中的作用。方法选择健康雌性Wistar大鼠24只,随机分为手术对照组,肝缺血90min组,肝缺血90min/再灌注120min组,每组8只。常规方法观察肝脏组织学改变,检测血清酶学水平和肝组织中髓过氧化物酶(MPO)含量,采用sABC免疫组织化学方法测定肝组织中NFkB的活化程度。结果手术对照组肝组织形态正常,无NFkB活化,肝功能酶学和MPO正常水平;缺血组动物肝细胞索排列紊乱,肝小叶变形,肝细胞和内皮细胞普遍水肿变性,NFkB呈中重度活化,血清酶学和MPO水平升高(P<0.01);肝缺血/再灌注组肝组织在缺血组改变基础上合并中央区局灶性肝细胞坏死,血窦内微血栓形成,汇管区中性粒细胞浸润,NFkB活化最为明显,血清酶学和MPO升高最为显著(P<0.01)。结论肝缺血再灌注时,NFkB被活化,使中性粒细胞组织浸润,对肝脏缺血再灌注损伤病理过程起到重要的作用。     

Impact of inhibition of complement by sCR1 on hepatic microcirculation after warm ischemia.

Recent observations provide evidence that complement is implicated as an important factor in the pathophysiology of ischemia/reperfusion injury (IRI). Here, we assessed the effects of complement inhibition on hepatic microcirculation by in vivo microscopy (IVM) using a rat model of warm hepatic ischemia clamping the left pedicle for 70 min. Ten animals received the physiological complement regulator soluble complement receptor type 1 (sCR1) intravenously 1 min prior to reperfusion. Controls were given an equal amount of Ringer's solution (n = 10). Microvascular perfusion and leukocyte adhesion were studied 30 to 100 min after reperfusion by IVM. Microvascular perfusion in hepatic sinusoids was significantly improved in the sCR1 group (80.6 +/- 0.6% of all observed sinusoids were perfused [sCR1] vs 67.3 +/- 1.2% [controls]). The number of adherent leukocytes was reduced in sinusoids (49.9 +/- 3.4 [sCR1] vs 312.3 +/- 14.2 in controls [adherent leukocytes per square millimeter of liver surface]; P < 0.001) as well as in postsinusoidal venules after sCR1 treatment (230.9 +/- 21.7 [sCR1] vs 1906.5 +/- 93.5 [controls] [adherent leukocytes per square millimeter of endothelial surface]; P < 0.001). Reflecting reduced hepatocyte injury, liver transaminases were decreased significantly upon sCR1 treatment compared to controls. Our results provide further evidence that complement plays a decisive role in warm hepatic IRI. Therefore, we conclude that complement inhibition by sCR1 is effective as a therapeutical approach to reduce microcirculatory disorders after reperfusion following warm organ ischemia.     

Effect of N—desulfated heparin on hepatic／renal ischemia reperfusion injury in rats

AIM：To invesigate the effect of N-desulfated heparin on hepatic/renal ischemia and reperfusion injury in rats.METHODS:Using rat models of 60minutes hepatic of renal ischemia followed by 1h,3h,6hand24h reperfusion.animals were randomly divided into following groups,the sham operated controls,ischemic group receiving only normal saline,and treated group receiving N-desulfated heparin at a dose of 12mg/kg at 5minutes before reperfusion.P-selectin expression was detected in hepatic/renal tissues with immunohistochemistry method.RESULTS:P-selectin expression,serumALT,AST,BUNand Cr levels were significantly increased during60minute ischemia and 1h,3h,6hand24hreperfusion.while the increment was significantly inhibited,and hepatic/renal pathology observed by light microscopy was remarkably improved by treatment with the N-desulfated heparin.Furthermore.the heparin was found no effects on PT and KPTT.CONCLUSION:P-selectin might mediate neutrophil infitration and contribute to hepatic/renai ischemia and reperfusion.THe N-desulfated heparin might prevent hepatic/renal admage induced by ischemia and reperfusion injury without significant anticoagulant activity.