Pyrrolidine dithiocarbamate prevents 60 minutes of warm mesenteric ischemia/reperfusion injury in rats

BACKGROUND: Pyrrolidine dithiocarbamate (PDTC) is a low-molecular-weight thiol antioxidant and potent inhibitor of nuclear factor-kappaB (NF-kappaB) activation. It has been shown to attenuate harmful effects of ischemia/reperfusion (I/R) injury in many organs. In recent animal studies, destructive effects of reperfusion injury has been demonstrated. In this study, we aimed to investigate whether PDTC prevents harmful effects of superior mesenteric I/R injury in rats. METHODS: Wistar-albino rats were randomly allocated into the following 4 groups: (1) sham-operated group--these animals underwent laparotomy without I/R injury (group I, n = 12); (2) sham+PDTC group--identical to sham-operated rats except for the administration of PDTC (100 mg/kg intravenous bolus) 30 minutes prior to the commencement of the experimental period (group II, n = 12); (3) I/R group--these animals underwent laparotomy and 60 minutes of ischemia followed by 120 minutes of reperfusion (group III, n = 12); (4) PDTC-treated group (100 mg/kg, intravenously, before the I/R, group IV, n = 12). All animals were killed, and intestinal tissue samples were obtained for investigation of intestinal mucosal injury, myeloperoxidase (MPO) activity, malondialdehyde (MDA) levels, glutathione (GSH) levels, and intestinal edema. RESULTS: There was a statistically significant decrease in GSH levels, along with an increase in intestinal mucosal injury scores, MPO activity, MDA levels, and intestinal tissue wet-to-dry weight ratios in group III when compared to groups I, II, and IV (P < .05). However, PDTC treatment led to a statistically significant increase in GSH levels, along with a decrease in intestinal mucosal injury scores, MPO activity, MDA levels, and intestinal tissue wet-to-dry weight ratios in group IV (P < .05). CONCLUSIONS: This study showed that PDTC treatment significantly prevented the reperfusion injury caused by superior mesenteric I/R. Further clinical studies are needed to clarify whether PDTC may be a useful therapeutic agent to use in particular operations where the reperfusion injury occurs.     

Effect of resveratrol on oxidative stress enzymes in rats subjected to 70% partial hepatectomy

This experimental study investigated the antioxidant status of rats after resveratrol (R) treatment following 70% partial hepatectomy. Thirty Wistar albino rats (200 to 250 g) were divided among: groups A and B (n = 10 each) underwent laparotomy and 70% partial hepatectomy (PH). Whereas rats in group A received resveratrol 60 mg/d per nasogastric tube for 7 days before and 3 days after PH (PH + R), those in group B underwent PH only. Rats in group C (n = 10) were subjected to a sham operation. Significant increases in tissue levels of reduced glutathione (GSH) and decreased malondialdehyde (MDA) levels were observed in the PH group receiving R compared with those of the PH group (P < .001 for all). Comparison of these parameters with those of the sham group revealed significantly higher tissue levels of GSH and lower MDA levels among sham-operated compared with PH + R and PH groups (P < .001 for all). Concerning the NO levels, a trend to a slightly decrease was observed in the PH + R group (P < .06). Interleukin-6 levels showed significant decreases in both PH + R and PH groups (P < .001 and P < .05, respectively). The tissue GSH levels were slightly decreased in PH + R (P < .05), and decreased in the PH group compared with the controls (P = .002). We have suggested that patients undergoing living donor liver transplantation would likely benefit from prophylactic treatment with foods having resveratrol.     

Curcumin Nutrition for the Prevention of Mesenteric Ischemia-Reperfusion Injury: An Experimental Rodent Model

Background

Curcumin is an anti-oxidant molecule known to be a potent inhibitor of nuclear factor-κB (NF-κB). It has been shown to attenuate ischemia/reperfusion (I/R) injury in several organ systems. In this study, we sought to investigate the effects of curcumin on the prevention of superior mesenteric artery I/R injury in rats.

Methods

Wistar albino rats were randomly allocated to 3 groups: group I, sham operated (n = 10); group II, I/R injury only (n = 10); group III, curcumin-treated I/R cohort (n = 10). Group I animals underwent laparotomy without I/R injury. After group II animals underwent laparotomy, 60 minutes of superior mesenteric artery ligation were followed by 3 hours of reperfusion. In the curcumin group, 15 days before I/R, curcumin (40 mg/kg) was administered by gastric gavage. All animals were sacrificed at the end of reperfusion. Intestinal tissue samples were obtained to investigate intestinal mucosal injury; in addition we estimated levels of myeloperoxidase (MPO) activity, malondialdehyde (MDA), nitric oxide (NO), glutathione (GSH), interleukin (IL)-6, and tumor necrosis factor (TNF)-α.

Results

There were statistically significant decreases in GSH levels, along with an increase in intestinal mucosal injury scores, MPO activity, MDA levels, NO, IL-6, and TNF-α in group I when compared with groups II and III (P = .01). Curcumin treatment in group III produced a significant increase in GSH levels, as well as a decrease in intestinal mucosal injury scores, MPO activity, MDA, and NO levels when compared with group II (P < .05).

Conclusion

This study showed that curcumin treatment significantly attenuated reperfusion injury in a superior mesenteric artery I/R model in rats.     

Protective effect of resveratrol, a red wine constituent polyphenol, on rats subjected to portal vein thrombosis

This experimental study investigated the prophylactic effects of the antioxidant and antiaggregant compound resveratrol (R) on portal vein thrombosis (PVT) in rats. Thirty rats weighing 200- 250 g were distributed in 3 groups: Group A (n = 10) and underwent PVT+R, Group B (n = 10) PVT alone, and Group C (n = 10) were subjected to a sham operation. Group A rats received R (60 mg/d per naso-gastric tube) for 10 days before PVT. Concerning antioxidant status, statistically significant increases in both tissue and plasma levels of reduced glutathione (GSH) and decrease in malondialdehyde (MDA) levels were observed in the PVT+R group compared with the PVT group (P < .001 for all). Comparison of these parameters with those of the sham group revealed significantly higher tissue and plasma levels of GSH and low MDA levels among the sham-operated group when compared with to the PVT+R or PVT groups (P < .001 for all). Concerning the antiaggregant status, significant increases of c-AMP levels were detected in rats treated with R before experiencing PVT (P < .001). Cyclic AMP levels in the sham group were significantly higher than those of either the PVT or PVT+R groups (P < .001). One may advise patients undergoing liver transplantation and carrying certain cardiovascular disease risk factors to ingest foods containing R to minimize PVT.     

The Evaluation of Protective Effects of FK-506 on Neural Ischemic-Reperfusion Injury: an Experimental Study

Abstract Objective: In this study, we aimed to delineate the mode of neuroprotective action of FK-506, and demonstrated that FK-506 could decrease oxidative stress and apoptotic cell death in an in vivo rat model of neural ischemia-reperfusion after hemorrhagic shock. Methods: Thirty rats were used as experimental subjects and divided into five equal groups. Group A rats (sham group, n = 6) were anesthetized and craniotomies were performed for collecting brain tissue samples. In group B ischemia-reperfusion (I/R + 1 h, n = 6), group C (I/R + 24 h, n = 6), group D (I/ R + 1 h FK-506, n = 6) and group E (I/R + 24 h FK-506, n = 6), systolic blood pressure of the rats decreased to 40–50% of the normal level via bleeding from the femoral vein. Thus, a hemorrhagic shock and ischemic neural tissue model was formed. The bloodwas retained and given to the remaining animals in groups B, C,Dand E via femoral vein for reperfusion 20 min after the procedure. In group D and E, 1 mg/kg FK-506 in 0.5 ml isotonic solution was administered to the rats 5 min before reperfusion. Group B and D rats were sacrificed after 1 h and group Cand E rats were sacrificed 24 h after reperfusion; the rats were sacrificed via bleeding associated with intracardiac puncture. Craniotomy was also performed in groups B, C, D and E and brain tissue samples were fixed using neutral buffered 10% formaldehyde solution for immunohistopathological examination as in group A. Brain tissue superoxide dismutase (SOD) activities, malondialdehyde (MDA) levels, tissue myeloperoxydase (MPO) activities and apoptotic cell analyses with Apo 2.7 immunohistochemically were also performed in all groups. Results: The result of the study revealed that the SOD activities were lower for groups B (I/R + 1 h) and C (I/ R + 24 h) than for group A (sham group) (p < 0.05). In addition, SOD activities were higher in groups D (I/ R + 1 h FK-506) and E (I/R + 24 h FK-506) than in groups B (I/R + 1 h) and C (I/R + 24 h) (p < 0.05). MDA levels, MPO activities and the number of apoptotic cells were lower in group A (sham group) than in groups B (I/R + 1 h) and C (I/R + 24 h) (p < 0.05). In addition to these MDA levels, MPO activities and the number of apoptotic cells were higher in groups B (I/R + 1 h) and C (I/R + 24 h) as compared to groups D (I/R + 1 h FK-506) and E (I/R + 24 h FK-506) (p < 0.05). Conclusion: The results suggest that the prophylactic use of FK-506 in an in situ ischemic neural tissue may prevent reperfusion injury.     

Resveratrol, a red wine polyphenol, protects spinal cord from ischemia-reperfusion injury

OBJECTIVE: The cardioprotective effect of red wine has been attributed to resveratrol. The resveratrol-induced protection against ischemia-reperfusion (I/R) injury has been documented in heart, kidney, and brain. Resveratrol scavenges free O(2) radicals and upregulates nitric oxide (NO). However, the presence of resveratrol-induced spinal cord protection against I/R injury has not been reported in the literature. The objective of this study was to evaluate the effects of resveratrol on neurologic functions, histopathologic changes, and NO metabolism following temporary spinal cord ischemia (SCI) in rabbits.Material and methods SCI was induced with occlusion of the infrarenal aorta in rabbits. In addition to the sham group (group S, n = 7), group C (n = 7) received vehicle 30 minutes before ischemia. Group R1 (n = 7) and R10 (n = 7) received 1 mg/kg and 10 mg/kg resveratrol instead of vehicle, respectively. Blood samples were taken to obtain nitrite/nitrate levels during the surgical procedure. After neurologic evaluation at the 48th hour of reperfusion, lumbar spinal cords were removed for histopathologic examination and malondialdehyde measurement as a marker of oxidative stress. RESULTS: Five animals in group C had paraplegia while 5 in group R10 had normal neurologic functions. The average Tarlov score of group R10 was significantly higher than that the score of group C (4.1 +/- 1.2, vs 1.2 +/- 2.2; P =.014). Histopathologic examination revealed higher neuronal viability index in group R10 compared with that of group C (0.82 +/- 0.24 vs. 0.46 +/- 0.34; P =.018). Nitrite/nitrate levels decreased in group C (from 357 +/- 20.15 micromol/L to 281 +/- 47.9 micromol/L; P <.01) whereas they increased both in group R1 and group R10 (from 287+/-28 micromol/L to 310 +/- 33.9 micromol/L and from 296 +/- 106 micromol/L to 339 +/- 87 micromol/L, respectively) during SCI. Malondialdehyde levels of group R10 was lower than those of group C (55 +/- 12.9 nmol/mg protein vs 83.9 +/- 15.1 nmol/mg protein; P =.001, respectively). CONCLUSIONS: In this model of SCI, resveratrol decreased oxidative stress, increased NO release, and protected spinal cord from I/R injury. Resveratrol-induced neuroprotection is probably mediated by its antioxidant and NO promoting properties. Before considering the clinical use of this natural antioxidant, further research is warranted about its mechanism of effects, timing, and optimum dose. CLINICAL RELEVANCE: Paraplegia that results from spinal cord ischemia is a catastrophic complication of thoracic and thoracoabdominal aorta surgical procedures. Despite several surgical modifications and pharmacologic approaches, paraplegia has not been totally eliminated. On clinical grounds, the efficiency of currently used pharmacologic agents to prevent spinal cord injury during thoracic and thoracoabdominal aorta surgery is very limited and their benefit is controversial. Preischemic infusion of resveratrol protects the spinal cord from ischemia reperfusion injury in rabbits. Following clarification of the underlying protective mechanism, optimal dose, and timing, resveratrol may used in humans as an adjunct to eliminate this catastrophic complication.     

Glutathione synthesis in intestinal ischaemia-reperfusion injury: effects of moderate hypothermia

Purpose

Intestinal glutathione (GSH) levels are dramatically decreased after intestinal ischaemia and reperfusion (I/R) injury. Hypothermia has protective effects during I/R injury. The aim of this study was to determine the effects of intestinal I/R and hypothermia on GSH synthesis in erythrocytes and ileum.

Methods

Adult male rats (n = 8 per group) underwent superior mesenteric artery occlusion for 60 minutes followed by 90-minute reperfusion or sham operation (control) for 150 minutes. Animals were maintained at either normothermia or moderate hypothermia. All rats received intravenous d₂-glycine as a GSH synthesis precursor until the end of the experiment. Ileum and erythrocyte samples were analysed for enrichment of d₂-glycine and GSH. The ratio of d₂-enrichment in GSH to that in the glycine precursor represents GSH synthesis.

Results

In erythrocytes, GSH synthesis was increased by normothermic I/R but decreased to control levels by hypothermic I/R. Ileal GSH synthesis was unaffected by hypothermia in sham animals but was significantly decreased by I/R at normothermia (P < .001). Hypothermic I/R, however, caused significant preservation of GSH synthesis so that GSH/Gly ratio was similar to controls and significantly higher than I/R at normothermia (P < .05).

Conclusions

Intestinal I/R leads to decreased ileal GSH synthesis, which could contribute to GSH depletion. Hypothermia preserves GSH synthesis during intestinal I/R injury, and this could protect from further tissue damage. We speculate that reactive species released during I/R injury impair the enzymes of GSH synthesis, whereas these enzymes are protected by moderate hypothermia.     

阿魏酸钠对CCL4致肝硬化大鼠肝缺血再灌注损伤的影响

目的:研究阿魏酸钠(SF)对肝硬化大鼠肝脏缺血再灌注(I/R)损伤的保护作用.方法:用50%四氯化碳油溶液皮下注射的方法制作肝硬化大鼠模型,将30只肝硬化大鼠随机均分为3组.A组:假手术组(10只);B组:对照组(10只);C组:SF保护组(10只).B、C组分别从尾静脉缓慢注入生理盐水1.5 mL、SF 1.5 mL(150 mg/kg)后,完全阻断大鼠肝门血流30 min,比较各组肝脏再灌注2 h后的肝功能,肝组织抗氧化能力、一氧化氮(NO)含量及肝脏形态学改变.结果:肝脏再灌注2 h时,与对照组比较,SF保护组大鼠肝组织丙二醛(MDA)含量显著减少(P＜0.01),超氧化物歧化酶(SOD)和NO含量显著增高(P＜0.01),血清丙氨酸氨基转移酶(ALT)、天门冬酸氨基转移酶(AST)、乳酸脱氢酶(LDH)活性显著降低(P＜0.01),对肝脏显微结构和超微结构损伤较轻.结论:SF对肝硬化大鼠肝I/R损伤有明显的保护作用.     

Polyphenol (-)-epigallocatechin gallate protection from ischemia/reperfusion-induced renal injury in normotensive and hypertensive rats

INTRODUCTION: The effect of epigallocatechin gallate (EGCG) in an in vivo renal model of ischemia with reperfusion (I/R) was compared between normotensive (WKR) and hypertensive (SHR) rats. METHODS: WKR (groups I, II, III) and SHR groups (groups IV, V, VI) were divided into three types. Groups I and IV were sham-operated animals; groups II and V were subjected to 45 minutes of renal I/R; and groups III and VI received 10 mg/kg EGCG intravenously at the time of reperfusion. Three days after renal I/R, we compared renal function markers, malondialdehyde (MDA), and histologic changes. RESULTS: Following renal I/R, levels of blood urea nitrogen (BUN) and serum creatinine (sCr) were increased and serum creatinine clearance (CrCl) decreased in group V compared to group II (P < .001). Those receiving EGCG treatment (groups III and VI) had decreased BUN and sCr compared to non-EGCG I/R groups (P < .001), but not surprisingly, higher than sham groups. CrCl was lowest in the SHR groups. The MDA was significantly decreased after EGCG treatment (P = .028 in group III, P = .002 in group VI). Following renal I/R, tissue necrosis was more severe among SHR (P < .001). However, the ratio of regeneration to damage significantly increased in SHR after EGCG treatment. CONCLUSIONS: The reperfusion injury was greater among SHR compared with WKR in terms of renal function, lipid peroxidation, and tissue damage. EGCG treatment significantly ameliorated renal impairment and promoted tissue regeneration following renal I/R.     

Activated protein C attenuates intestinal reperfusion-induced acute lung injury: an experimental study in a rat model

BACKGROUND: Activated protein C (APC) is a serine protease with anticoagulant and anti-inflammatory activities. APC has been shown to attenuate local deleterious effects of ischemia/reperfusion (I/R) injury in many organs. We aimed to investigate the effects of APC on lung reperfusion injury induced by superior mesenteric occlusion. METHODS: Male Wistar-Albino rats were allocated into 4 groups: (1) sham-operated group, laparotomy without I/R injury (n = 12); (2) sham + APC group, identical to group 1 except for APC treatment (n = 12); (3) intestinal I/R group, 60 minutes of ischemia followed by 3 hours of reperfusion (n = 12); and (4) I/R + APC-treated group, 100 microg/kg injection of APC intravenously, 15 minutes before reperfusion (n = 12). Evans blue dye was injected into half of the rats in all groups. We assessed the degree of pulmonary tissue injury by measuring activities of oxidative and antioxidative enzymes, as well as nitrate (NO(3)(-))/nitrite (NO(2)(-)) levels, biochemically. We evaluated acute lung injury (ALI) by establishing pulmonary neutrophil sequestration and ALI scoring histopathologically. Pulmonary edema was estimated by using Evans blue dye extravasation and wet/dry ratios. The plasma levels of proinflammatory cytokines and D-dimer were measured. RESULTS: APC treatment significantly reduced activities of oxidative enzymes and nitrate/nitrite levels in the lung tissues, and plasma levels of proinflammatory cytokines and D-dimer, and also significantly increased activities of antioxidative enzymes (P < .05). Pulmonary neutrophil sequestration and ALI scores were decreased significantly with APC administration (P < .05). In addition, APC treatment significantly alleviated pulmonary edema (P < .05). CONCLUSIONS: This study clearly showed that APC treatment significantly attenuated the lung reperfusion injury. Further clinical studies are required to clarify whether APC has a useful role in the reperfusion injury during particular surgeries in which I/R-induced organ injury occurs.     

Protective effects of glucagon-like peptide 2 on intestinal ischemia-reperfusion rats

Our objective was to evaluate the protective effects of glucagon-like peptide 2 (GLP-2) on intestinal ischemia/reperfusion (I/R) rats. Thirty-two rats were randomly assigned to four experimental groups, each of 8: Group A, sham rats underwent laparotomy only, without superior mesenteric artery (SMA) occlusion; Group B, I/R animals underwent laparotomy and occlusion of the SMA for 60 minutes followed by 120 minutes of reperfusion; Group C, I/R animals underwent intestinal I/R, and received pretreatment with GLP-2 for 3 days preoperatively; and Group D, I/R animals underwent intestinal I/R, received pretreatment with GLP-2 as above, and during the reperfusion phase were injected intravenously with GLP-2. After the reperfusion of intestinal ischemia, samples of intestinal mucosa, mesenteric lymph nodes (MLN) and blood were prepared for determination. In the pretreatment rats with GLP-2 (group C), Chiu's scores, bacterial colony counts, serum D-lactate, intestinal mucosal MDA and ET-1, and serum endotoxin, TNF-alpha and IL-6 were significantly reduced compared with intestinal I/R rats (group B). Administration of GLP-2 during the reperfusion phase following pretreatment (group D) showed further protective effects in comparison with the pretreatment rats (group C). We conclude that treatment with GLP-2 attenuates intestinal I/R injury, reduces bacterial translocation, inhibits the release of oxygen free radicals and ET-1, and may well inhibit the production of proinflammatory cytokines.     

The effects of glucose-insulin-potassium solution and BN 52021 in intestinal ischemia-reperfusion injury

The objective of this study was to investigate effects of glucose-insulin-potassium (GIK) solution and BN 52021, a platelet-activating factor antagonist, on intestinal ischemia-reperfusion injury. Fifty male Sprague-Dawley rats (200-225 g) were divided into 5 groups each containing 10 rats; group SO, sham operation group; group I, mesenteric ischemia group (for 30 minutes); group R, ischemia plus reperfusion (for 60 minutes); group BR, ischemia-reperfusion plus BN 52021; group GR, ischemia-reperfusion plus GIK solution. Samples for malondialdehyde (MDA) and ileum (for mucosal injury score) were obtained. The mucosal injury scores of group R were significantly higher than those of group I (4 +/-0.20 and 3 +/-0.16, respectively, p<0.0001). The scores of groups BR and GR were significantly lower than those of group R (p<0.0001 and p<0.0001, respectively). When it was compared with the injuries in BR and GR groups, similar results were obtained in both groups (p=0.190). Mean MDA levels of group R were significantly higher than those of group I, BR and GR (131.33 +/-3.99 nmol/g, 93.74 +/-3.22 nmol/g, 104.81 +/-2.56 and 100.34 +/-5.30, respectively, p<0.0001). MDA levels of group BR and GR were significantly lower than those of group I (p<0.0001 and p=0.003, respectively). These observations suggest that treatment with GIK solution and BN 52021 before reperfusion and during reperfusion period may be useful in decreasing intestinal reperfusion injury.     

Pyrrolidine Dithiocarbamate Reduces Lung Injury Caused by Mesenteric Ischemia/Reperfusion in a Rat Model

Background Pyrrolidine dithiocarbamate (PDTC) is a low-molecular thiol antioxidant and potent inhibitor of nuclear factor-κB (NF-κB) activation. It has been shown to attenuate local harmful effects of ischemia/reperfusion (I/R) injury in many organs. In this study, we aimed to study the effect of PDTC on lung reperfusion injury induced by superior mesenteric occlusion. Methods Male Wistar-albino rats randomized into three groups: (1) sham-operated control group (n = 12), laparotomy without I/R injury; (2) intestinal ischemia/reperfusion (I/R) group (n = 12), 60 min of ischemia by superior mesenteric occlusion followed by 2 h of reperfusion; and (3) I/R+PDTC-treated group (n = 12), 100 mg/kg injection of PDTC intravenously, 30 min after the commencement of reperfusion. Evans blue dye was injected to half of rats in all groups before the induction of I/R. We assessed the degree of pulmonary tissue injury biochemically by measuring malondialdehyde (MDA), glutathione (GSH), and nitric oxide (NO) levels, and histopathologically by establishing pulmonary neutrophil sequestration and acute lung injury scoring. Pulmonary edema was evaluated by Evans blue dye extravasation, as well as lung tissue wet/dry weight ratios. Results Pyrrolidine dithiocarbamate treatment significantly reduced the MDA and NO levels, and increased the GSH levels in the lung parenchyma, biochemically (p < 0.05), and atteneuated the pulmonary parenchymal damage, histopathologically (p < 0.05). However, pulmonary neutrophil sequestration was not affected by postischemic treatment with PDTC (p > 0.05). Pyrrolidine dithiocarbamate administration also significantly alleviated the formation of pulmonary edema, as evidenced by the decreased Evans blue dye extravasation and organ wet/dry weight ratios (p < 0.05). Conclusions This study showed that postischemic treatment with PDTC significantly attenuated the lung reperfusion injury. Further clinical studies are needed for better understanding of the specific mechanisms of PDTC protection against I/R-related organ injury and to clarify whether PDTC may be a useful therapeutic agent during particular operations where remote organ I/R injury occurs.     

右美托咪啶后处理对大鼠离体心脏缺血再灌注时线粒体损伤的影响

目的 探讨右美托咪啶后处理对大鼠离体心脏缺血再灌注时线粒体损伤的影响.方法 健康雌性Wistar大鼠,体重220～250 g,成功制备Langendorff离体灌注模型的40个心脏随机分为5组(n=8):缺血再灌注组(A组)、右美托咪啶10 nmol/L组(B组)、右美托咪啶100 nmol/L组(C组)、线粒体通透性转换孔开放剂苍术苷组(D组)及右美托咪啶联合苍术苷组(E组).离体心脏经K-H液平衡灌注20 min后,采用全心停灌40 min再灌注60 min的方法制备离体心脏缺血再灌注模型.于再灌注即刻B组、C组、D组和E组分别灌注含10 nmol/L右美托咪啶、100 nmol/L右美托咪啶、20μmol/L苍术苷、100 nmol/L右美托咪啶和20 μmol/L苍术苷的K-H液10 min.再灌注结束即刻取心尖组织,分离线粒体,测定SOD、Na+ -K+ -ATP酶、Ca2+-ATP酶活性和MDA和Ca2+含量.结果 与A组比较,B组和C组线粒体SOD、Na+ -K+ -ATP酶和Ca2+ -ATP酶活性升高,MDA和Ca2+含量降低(P＜0.05),D组和E组上述指标比较差异无统计学意义(P＞0.05);与C组比较,D组和E组线粒体SOD、Na+-K+-ATP酶和Ca2+ -ATP酶活性降低,MDA和Ca2+含量升高(P＜0.05),B组上述指标比较差异无统计学意义(P＞0.05).结论 右美托咪啶后处理可减轻大鼠离体心脏缺血再灌注时的线粒体损伤,其机制可能与抑制线粒体通透性转换孔开放有关.     

Protection of preconditioning, postconditioning and combined therapy against hepatic ishemia/reperfusion injury

Objective： To study the protective effect of ischenlic preconditioning （I-pre） and ischemic postconditioning （I- post） against ischenlia/reperfusion （I/R） injury in rat＇ s liver. Methods： Using rat model of hepatic segmental I/R injury, rats were divided into 5 groups： Group A （sham group）, Group B （I/R injury）, Group C （I-pre group）, Group D （I-post group ） and Group E （combined treatment of I-pre and I-post ）. Serum alanine aminotransferase （ ALT ）, aspartate aminotransferase （ AST）, malondiaidehyde （ MDA ）, glutathione （ GSH ）, superoxide dismutase （ SOD ）, glutathione peroxidase （GSH-Px） and myeloperoxidase （MPO） in hepatic tissues were determined, respectively. In addition, 7 days＇survival of Groups B, C, D and E were evaluated. Results. Compared with Group B, Groups C, D and E exhibited significantly decreased ALT and AST release, minimized tissue injury, suppressed values of MDA and MPO, increased activities of SOD, GSH-Px and GSH （P〈0.05 ）, as well as improved animal survival. The differences among Groups C, D and E were not statistically significant. Conclusions： I-pre, I-post and combined therapy of I-pre and I-post have protective effect against hepatic I/R injury, which is correlated with its function of reducing the production of reactive oxygen species, maintaining the activities of antioxidant systems and suppressing neutrophils recruitment. No additive effect can be obtained in Group E.     

Free Radical Scavenging Activity of Fullerenol on the Ischemia-reperfusion Intestine in Dogs

Fullerenol, a water-soluble C₆₀-fullerene derivative, has been demonstrated to have the capability to scavenge free radicals in vitro and in vivo. The purpose of this study was to investigate whether fullerenol can scavenge the free radicals that are massively induced during ischemia-reperfusion (I/R) injury of the small intestine, either preventively or therapeutically. Clamping the superior mesenteric artery and vein for 60 minutes to induce I/R injury was performed on male mongrel dogs. Thirty dogs were divided into three groups (10 in each): The control (C) group received no medication; the preventive (P) group received fullerenol (1 mg/kg) intravenously 30 minutes before ischemia; the therapeutic (T) group received the same dose of fullerenol immediately after reperfusion. This study was an experimental randomized trial. Intestinal segments were obtained 10, 20, 30, and 60 minutes after reperfusion; and blood samples and specimens of major organs were taken 60 minutes after reperfusion. Concentrations of lipid peroxidation products, including conjugated diene (CD) and malondialdehyde (MDA), and the level of glutathione (GSH) in intestinal tissue were determined. Serum indicators of liver and renal function were measured. Histologic examination of the small intestine and major organs were also performed. A significant increase in intestinal MDA and CD contents was detected at 30 and 60 minutes after reperfusion. The tissue GSH content, in contrast, was decreased 60 minutes after reperfusion. Administration of fullerenol diminished these changes both preventively and therapeutically. Liver and renal functions were within normal limits in all groups. Moreover no obvious histopathologic additional damage could be found in either the P or the T group. It is suggested that fullerenol can be considered a powerful scavenger for the free radicals induced by I/R injury of the small intestine.     

齐墩果酸预先给药对大鼠肝脏缺血再灌注损伤的影响

目的 探讨齐墩果酸预先给药对大鼠肝脏缺血再灌注损伤的影响.方法 清洁级健康雄性SD大鼠128只,体重230～250 g,随机分为4组(n=32):假手术组(S组)、缺血再灌注组(IR组)、羧甲基纤维素钠组(CMC组)和齐墩果酸预处理组(OA组).OA组胃内灌注齐墩果酸混悬液100 mg/kg,CMC组以相同容积的0.5%羧甲基纤维素钠溶液、S组与IR组以相同容积的饮用水替代,每天1次,连续7 d,第8天时IR组、CMC组和OA组采用阻断门静脉及肝动脉分支60 min后再灌注的方法制备肝脏缺血再灌注模型,S组仅分离胆管及门静脉、肝动脉分支.于再灌注即刻、3、6和12 h时取下腔静脉血样,测定血清ALT活性;取左肝中叶组织,测定SOD活性、MDA和谷胱甘肽(GSH)含量和磷酸化磷脂酰肌醇-3激酶(p-PI3K)、蛋白质丝氨酸苏氨酸激酶(Akt)、p-Akt、Bcl-2、Bax、p-Bad和Bad的表达水平,观察肝组织病理学结果.结果 与S组比较,IR组、CMC组和OA组再灌注期间血清ALT活性和肝组织MDA含量升高,肝组织SOD活性和GSH含量降低,p-PI3K、p-Akt、Bax、Bad、p-Bad表达上调,Bcl-2表达下调(P＜0.05);与IR组比较,OA组再灌注期间血清ALT活性和肝组织MDA含量降低,肝组织SOD活性和GSH含量升高,p-PIK、p-Akt、Bcl-2和p-Bad表达上调,Bad和Bax表达下调(P＜0.05),CMC组上述指标差异无统计学意义(P＞0.05);与CMC组比较,OA组再灌注期间血清ALT活性和肝组织MDA含量降低,肝组织SOD活性和GSH含量升高,p-PI3K、p-Akt、Bcl-2和p-Bad表达上调,Bad和Bax表达下调(P＜0.05).OA组肝组织病理学损伤较IR组减轻.结论 齐墩果酸预先给药可减轻大鼠肝脏缺血再灌注损伤,其机制可能与激活PI3K/Akt信号通路,抑制细胞凋亡有关.     

再灌注期间给予富氢液对大鼠全脑缺血再灌注损伤的影响

目的 评价再灌注期间给予富氢液对大鼠全脑缺血再灌注损伤的影响.方法 成年雄性SD大鼠72只,月龄2.0～2.5个月,体重260～300 g,采用随机数字表法,将其随机分为3组(n＝24):假手术组(S组)、脑缺血再灌注组(I/R组)和富氢液组(H组).I/R组和H组采用四血管阻塞法(缺血15 min)制备全脑缺血再灌注损伤模型.H组于再灌注6h时腹腔注射0.6 mmol/L富氢液5ml/kg,I/R组给予等容量生理盐水.再灌注24h时,每组处死18只大鼠,取海马组织,测定丙二醛(MDA)、肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)含量、NF-κB活性、活化的caspase-3表达;再灌注72 h时,处死6只大鼠,取脑组织,HE染色,光镜下观察海马CA1区病理学结果,进行海马CA1区正常锥体细胞计数.结果 与S组比较,I/R组海马组织MDA、TNF-α、IL-6含量和NF-κB活性升高,活化caspase-3表达上调,正常锥体细胞计数减少(P<0.05);与I/R组比较,H组海马组织MDA、TNF-α、IL-6含量和NF-κB活性降低,活化caspase-3表达下调,正常锥体细胞计数增多(P<0.05).H组脑组织海马CA1区病理学损伤程度轻于I/R组.结论 再灌注期间给予富氢液可减轻大鼠全脑缺血再灌注损伤,其机制与抑制脂质过氧化反应、炎性反应和细胞凋亡有关.     

Biochemical and morphological evaluation of ischemia-reperfusion injury in rat small bowel modulated by ischemic preconditioning

The objective of this study was to evaluate the effect of ischemic preconditioning upon lesions produced by ischemia-reperfusion of the small intestine. Thirty EPM-1 Wistar rats were randomly distributed into three groups: ischemic preconditioning (IPC; n = 12), ischemia-reperfusion (I/R; n = 12), and control (C; n = 6). Laparotomy permitted isolation of the mesenteric artery for clamping. The animals were heparinized and hydrated. IPC was induced by: 10 minutes of ischemia followed by 10 minutes of reperfusion and then 50 minutes ischemia followed by another 30 minutes reperfusion. Group I/R was submitted to the same protocol except for the 20 minutes of preconditioning. Group C animals underwent only laparotomy for 100 minutes. After reperfusion small intestine fragments were examined histologically. Blood samples were obtained to measure LDH and lactate prior to euthanasia. Lactate values were significantly lower in the IPC as compared to I/R group, 39 versus 67 mg/dL, respectively (P < or =.05). However, neither IPC (grade 3) lesions of the mucosa versus I/R (grade 4) nor LDH values (PCI = 680, I/R = 873 U/L) were statistically different. Thus No morphological evidence of protection was observed following ischemic preconditioning.     

不同时间的缺血预处理对肝硬化大鼠缺血再灌注损伤的保护作用

目的 探讨缺血预处理(IPC)对肝硬化大鼠缺血再灌注损伤(I/R)的保护作用,并寻找对肝硬化I/R保护作用的最佳有效时间窗和理想方案.方法 通过构建正常大鼠及肝硬化大鼠模型,以正常肝脏I/R(A组)和正常肝脏10-10 min-IPC方案(B组)为对照组,肝硬化组则分别施行单纯I/R(C组)、5-10 min(D组)、8-10min(E组)、10-10 min(F组)及15-10 min(G组)的IPC方案,每组18只,分别在术后1 h、4 h及24 h三个时间点采静脉血,检测血清ALT、AST、LDH及肝组织中MDA、MPO、NO、SOD水平,评价肝功能及肝脏组织炎性浸润及抗损伤程度.结果 肝脏缺血30 min后肝脏功能受损明显,表现为各组的ALT、AST、LDH水平升高,尤以再灌注4 h时显著(P<0.05),但经过缺血预处理后,各IPC组中的NO、MDA、MPO及SOD水平亦显著高于其对应的I/R组,以E组的差别有显著意义(P<0.05).结论 10-10 min的IPC方案对于正常肝脏I/R确有保护作用,而8-10 min的IPC方案能最有效地启动对肝硬化大鼠肝脏I/R的保护作用.