Role In Ischemia-reperfusion Research Articles

Seabuckthorn Pulp Oil Protects against Myocardial Ischemia-Reperfusion Injury in Rats through Activation of Akt/eNOS.

Seabuckthorn (SBT) pulp oil obtained from the fruits of seabuckthorn [Hippophae rhamnoides L. (Elaeagnaceae)] has been used traditionally for its medicinal and nutritional properties. However, its role in ischemia–reperfusion (IR) injury of myocardium in rats has not been elucidated so far. The present study reports the cardioprotective effect of SBT pulp oil in IR-induced model of myocardial infarction in rats and underlying mechanism mediating activation of Akt/eNOS signaling pathway. Male albino Wistar rats were orally administered SBT pulp oil (5, 10, and 20 ml/kg/day) or saline for 30 days. On the day 31, ischemia was induced by one-stage ligation of left anterior descending coronary artery for 45 min followed by reperfusion for 60 min. SBT pulp oil pretreatment at the dose of 20 ml/kg observed to stabilize cardiac function and myocardial antioxidants such as glutathione, superoxide dismutase, catalase, and inhibited lipid peroxidation evidenced by reduced malondialdehyde levels as compared to IR-control group. SBT pulp oil also improved hemodynamic and contractile function and decreased tumor necrosis factor and activities of myocyte injury marker enzymes; lactate dehydrogenase and creatine kinase-MB. Additionally, a remarkable rise in expression of pAkt–eNOS, Bcl-2 and decline in expression of IKKβ/NF-κB and Bax was observed in the myocardium. The histopathological and ultrastructural salvage of cardiomyocytes further supports the cardioprotective effect of SBT pulp oil. Based on findings, it can be concluded that SBT pulp oil protects against myocardial IR injury mediating favorable modulation of Akt-eNOS and IKKβ/NF-κB expression.

Rapamycin protects kidney against ischemia reperfusion injury through recruitment of NKT cells.

BackgroundNKT cells play a protective role in ischemia reperfusion (IR) injury, of which the trafficking in the body and recruitment in injured organs can be influenced by immunosuppressive therapy. Therefore, we investigated the effects of rapamycin on kidneys exposed to IR injury in early stage and on trafficking of NKT cells in a murine model.Material and methodsBalb/c mice were subjected to kidney 30 min ischemia followed by 24 h reperfusion. Rapamycin (2.5 ml/kg) was administered by gavage daily, starting 1 day before the operation. Renal function and histological changes were assessed. The proportion of NKT cells in peripheral blood, spleen and kidney was detected by flow cytometry. The chemokines and corresponding receptor involved in NKT cell trafficking were determined by RT-PCR and flow cytometry respectively.ResultsRapamycin significantly improved renal function and ameliorated histological injury. In rapamycin-treated group, the proportion of NKT cells in spleen was significantly decreased but increased in peripheral blood and kidney. In addition, the CXCR3+ NKT cell in the kidney increased remarkably in the rapamycin-treated group. The chemokines, CXCL9 and CXCL10, as the ligands of CXCR3, were also increased in the rapamycin-treated kidney.ConclusionsRapamycin may recruit NKT cells from spleen to the IR-induced kidney to ameliorate renal IR injury in the early stage.

Histopathological Changes at Colonic Anastomotic Site after Ischemia Reperfusion Injury: Role of Aminoguanidine in Experimental Model

Inducible nitric oxide synthase (iNOS) has a significant role in ischemia reperfusion (I-R) injury. I-R injury impairs the healing at the intestinal anastomotic site. This study was designed to assess the role of aminoguanidine (AG, a selective inhibitor of iNOS), in healing at the colonic anastomotic site after intestinal I-R injury in rats. Methods: Female Wistar rats (n = 60) were divided into three groups. Group I (n = 15): sham operation, Group II (n = 15): I-R injury and anastomosis, and Group III (n = 30): I-R injury + anastomosis + AG-50 mg/kg. On the 7th postoperative day, relaparotomy was done and 4 cm of the colon with an intact area of the anastomosis was resected. Bursting pressure and histology at the anastomotic site were assessed. The bursting pressure was significantly higher in Group III. In addition, bridging parameters (i.e., mucosal continuity, muscular continuity, re-epithelization, and granulation tissue), collagen pattern, and collagen density were significantly better in Group III. While the polymorphonuclear density was higher in Group II, suggestive of delayed healing. AG, by decreasing inflammation and increasing collagen content in an organized pattern, helped in preventing I-R injury at the site of colonic anastomosis in rats.

Protective Effect of SGK1 in Rat Hippocampal Neurons Subjected to Ischemia Reperfusion

Background/Aims: To investigate the protective effect of SGK1 (serum- and glucocorticoid-inducible protein kinase 1) in rat hippocampal neurons in vitro and in vivo following ischemia reperfusion (I/R). Methods: Isolated rat hippocampal neurons were subjected to 2 h of oxygen and glucose deprivation (OGD) then returned to normoxic conditions for 10, 30 or 60 min. Cell apoptosis and protein expression of SGK1 were analyzed. To examine SGK1 function, we overexpressed SGK1 in rat hippocampal neurons. Finally we examined the involvement of PI3K/Akt/GSK3β signaling by treating the cells (untransfected or transfected with expression vector encoding SGK1) with the PI3K inhibitor LY294002. Findings were confirmed in vivo in a rat model of middle cerebral artery occlusion. Results: I/R caused a time-dependent increase in apoptosis, both in vitro and in vivo. SGK1 protein levels decreased significantly under the same conditions. Overexpression of SGK1 reduced apoptosis following OGD or I/R compared to cells transfected with empty vector and subjected to the same treatment, or sham-operated animals. Addition of LY294002 revealed that the action of SGK1 in suppressing apoptosis was mediated by the PI3K/Akt/GSK3β pathway. Conclusion: SGK1 plays a protective role in ischemia reperfusion in rat hippocampal neurons, exerting its effects via the PI3K/Akt/GSK3β pathway.

Dose-Effects of Aorta-Infused Clenbuterol on Spinal Cord Ischemia-Reperfusion Injury in Rabbits

BackgroundThe β2 adrenergic receptor (β2AR) plays an important role in ischemia-reperfusion (I/R) injury in various organs. Recently, a selective β2AR agonist clenbuterol was suggested to protect against cerebral I/R injury. This study was designed to investigate changes of β2ARs after spinal cord I/R injury and dose-effects of aorta-infused clenbuterol on spinal cord I/R injury in rabbits.MethodsSpinal cord ischemia was induced in New Zealand white rabbits by infrarenal abdominal aortic occlusion with a balloon catheter for 30 minutes except the sham group. During occlusion, nothing (I/R group), normal saline (NS group) or clenbuterol at different doses of 0.005, 0.01, 0.05, 0.1, 0.5, or 1 mg/kg (C0.005, C0.01, C0.05, C0.1, C0.5, and C1 groups) was infused into the occluded aortic segments. The hemodynamic data, blood glucose and serum electrolytes were measured during experimental period. Neurological function was assessed according to the modified Tarlov scales until 48 hours after reperfusion. After that, the lumbar spinal cord was harvested for β2AR immunohistochemistry and histopathologic evaluation in the anterior horns.ResultsThe β2AR expression in the anterior horns of the spinal cord was significantly higher in the I/R group than in the sham group. Tarlov scores and the number of viable α-motor neurons were higher in C0.01-C0.5 groups than in the NS group, C0.005 and C1 groups and were highest in the C0.1 group. Hypotension and hyperglycemia were found in the C1 group.Conclusionβ2ARs in the anterior horn were upregulated after spinal cord I/R injury. Aortic-infused clenbuterol (0.01–0.5 mg/kg) can attenuate spinal cord I/R injury dose-dependently during the ischemic period. The Optimal dosage was 0.1 mg/kg. Activation of β2AR could be a new therapeutic strategy for the treatment of spinal cord I/R injury.

Treatment of Rats With Hypolipidemic Compound Pirinixic Acid Protects Their Hearts Against Ischemic Injury: Are Mitochondrial KATP Channels and Reactive Oxygen Species Involved?

Hypolipidemic compound pirinixic acid (WY-14643, WY) is known to exert pleiotropic (other than primary) effects, such as activation of peroxisome proliferator-activated receptors (PPAR-alpha), transcription factors regulating different cardiac functions. Their role in ischemia-reperfusion (I/R) injury and cardioprotection is less clear, although protective effects of PPAR agonists have been documented. This study was designed to explore the effects of WY on the I/R injury in the rat heart and potential mechanisms involved, including mitochondrial K(ATP) channels (mitoK(ATP)) opening and production of reactive oxygen species (ROS). Langendorff-perfused hearts of rats intragastrally treated with WY (3 mg/kg/day) for 5 days and of control animals were subjected to 30-min global ischemia and 2-h reperfusion with or without 15-min perfusion with mitoK(ATP) blocker 5-hydroxydecanoate (5-HD) prior to I/R. Evaluation of the infarct size (IS, TTC staining) served as the main end-point of protection. Lipid peroxidation (a marker of ROS production) was determined by measurement of myocardial concentration of conjugated dienes (CD), whereas protein expression of endothelial NO synthase was analysed by Western blotting. A 2-fold increase in the cardiac protein levels of eNOS after treatment with WY was accompanied by lower post-I/R levels of CD compared with those in the hearts of untreated controls, although WY itself enhanced ROS generation prior to ischemia. IS was reduced by 47 % in the hearts of WY-treated rats (P<0.05), and this effect was reversed by 5-HD. Results suggest that PPAR-alpha activation may confer protection against lethal I/R injury in the rat heart that involves up-regulation of eNOS, mitoK(ATP) opening and reduced oxidative stress during I/R.

Anti-Apoptotic Pro-Survival Effect of Clotrimazole in a Normothermic Ischemia Reperfusion Injury Animal Model

Increasing evidence suggests that apoptosis plays a critical role in ischemia reperfusion (IR)-mediated liver injury. Clotrimazole (CTZ) is a potent antimycotic drug that also has a free radical scavenger activity. This study investigated the possible anti-apoptotic, pro-survival role of CTZ in hepatic IR injury in rats. Male Sprague-Dawley rats were divided into three groups: sham, control, and CTZ-treated (n = 10 each). Control and CTZ-treated animals were subjected to 60 min of normothermic ischemia of the left lateral lobe of the liver followed by 6 h of reperfusion. Animals were then sacrificed, the liver excised, and blood samples collected. CTZ induced a significant increase in expression of anti-apoptotic Bcl-xL protein. Serum levels of aspartate transaminase and alanine transaminase were significantly lower in CTZ-treated animals than in controls. Histopathologically, tissue damage in the form of apoptosis was significantly lower in CTZ-treated animals than in controls. Expression of the activated form of caspase-3 and the cleaved form of its substrate, poly-ADP-ribose polymerase, decreased significantly in the CTZ-treated group compared with controls. CTZ increased the expression of phospho-p 44/42 ERK1/2 and decreased the phosphorylated form of JNK, without affecting p38 MAPK. CTZ protects the liver against IR apoptosis in rats through overexpression of the anti-apoptotic protein Bcl-xL. Other pro-survival pathways such as phospho-p 44/42 ERK1/2 kinase are also activated while JNK is down-regulated.

NADPH Oxidase in Bone Marrow–Derived Cells Mediates Pulmonary Ischemia-Reperfusion Injury

Reactive oxygen species (ROS) play a crucial role in ischemia-reperfusion (IR) injury after lung transplantation. We hypothesized that NADPH oxidase derived from bone marrow (BM) cells contributes importantly to lung IR injury. An in vivo mouse model of lung IR injury was employed. Wild-type C57BL/6 (WT) mice, p47(phox) knockout (p47(phox)-/-) mice, or chimeras created by BM transplantation between WT and p47(phox)-/- mice were assigned to either Sham (left thoracotomy) or six study groups that underwent IR (1 h left hilar occlusion and 2 h reperfusion). After reperfusion, pulmonary function was assessed using an isolated, buffer-perfused lung system. Lung injury was assessed by measuring vascular permeability (via Evans blue dye), edema, neutrophil infiltration (via myeloperoxidase [MPO]), lipid peroxidation (via malondialdyhyde [MDA]), and expression of proinflammatory cytokines. Lung IR resulted in significantly increased MDA in WT mice, indicative of oxidative stress. WT mice treated with apocynin (an NADPH oxidase inhibitor) and p47(phox)-/- mice displayed significantly reduced pulmonary dysfunction and injury (vascular permeability, edema, MPO, and MDA). In BM chimeras, significantly reduced pulmonary dysfunction and injury occurred after IR in p47(phox)-/--->WT chimeras (donor-->recipient) but not WT-->p47(phox)-/- chimeras. Induction of TNF-alpha, IL-17, IL-6, RANTES (CCL5), KC (CXCL1), MIP-2 (CXCL2), and MCP-1 (CCL2) was significantly reduced after IR in NADPH oxidase-deficient mice and p47(phox)-/--->WT chimeras but not WT-->p47(phox)-/- chimeras. These results indicate that NADPH oxidase-generated ROS specifically from BM-derived cells contributes importantly to lung IR injury. NADPH oxidase may represent a novel therapeutic target for the treatment of IR injury after lung transplantation.

Liver HIF-1 Alpha Induction Precedes Apoptosis Following Normothermic Ischemia-Reperfusion in Rats

Apoptosis plays an important role in ischemia-reperfusion (I-R) injury during liver transplantation. The hypoxia-inducible factor alpha (HIF-1α) may trigger liver apoptosis following I-R through the induction of hypoxically regulated genes. The aim of this study was to evaluate the effect of normothermic liver I-R on HIF-1α expression and apoptosis in rats. Segmental normothermic ischemia of the liver was induced in rats for 120 minutes. Liver extracts from either ischemic or nonischemic lobes were prepared at 0, 1, 3, and 6 hours after reperfusion. Liver HIF-1α protein expression was examined by Western blot analysis. Liver apoptosis was quantified using terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick end labeling assay. Normothermic I-R resulted in a significant ( P < .05) increase in liver HIF-1α protein levels 1 and 3 hours after reperfusion. Liver apoptosis was significantly ( P < .005) increased at 3 and 6 hours after reperfusion. In conclusion, normothermic liver I-R leads to increased liver expression of HIF-1α and apoptosis.

Abstract 1396: Mitigation Of Cardiac Injury By Sulfaphenazole, A CYP2C9 Inhibitor Through Involvement Of Inducible Nitric Oxide Synthase (iNOS) in Post-ischemic Heart

Cytochrome P450 enzymes play a significant role in ischemia-reperfusion (I/R) injury. Sulfaphenazole (SFZ), a potent CYP2C9 inhibitor, is known to reduce I/R injury. However, the mechanism of its cardioprotective effects and the role of nitric oxide (NO) is not clear. Objective : Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are important mediators of I/R injury. The objective of this study was to determine how SFZ treatment modulates myocardial tissue oxygenation (pO 2 ) and RNS generation in vivo . Methods: Myocardial infarction was induced in rats by ligating the left anterior descending coronary artery (LAD) for 30 min, followed by 24 h of reperfusion. The study was divided into 4 groups: Untreated I/R control, SFZ, L-NAME, and SFZ+L-NAME. L-NAME (100 mg/kg/day), a nitric oxide synthase inhibitor, was given orally for 3 days prior to LAD ligation. SFZ (1.5 mg/kg, ip) was injected 30 min prior to LAD ligation. Oxygen-sensing crystals were implanted into the LV wall and the rat was placed in an L-band (1.2 GHz) electron paramagnetic resonance (EPR) spectrometer for measurement of myocardial tissue pO 2 during I/R injury. Hemodynamic data was collected with a microtip catheter. Infarct size was measured after 24 h of reperfusion. Superoxide generation was determined by dihydroethidium fluorescence imaging. Immunohistological staining was performed for nitrotyrosine and iNOS. Results: After LAD ligation, pO 2 decreased from 18 mmHg baseline to &lt;2 mmHg. At reperfusion, there was a significant myocardial hyperoxygenation in SFZ-treated rats compared to control group (45.0±1.3 vs. 34.0±2.0 mmHg, P&lt;0.05). In L-NAME and L-NAME+SFZ-treated rats, there was a significant reduction in pO 2 (24.0±1.6 and 26.0±2.3 mmHg, respectively). Compared to control, SFZ treatment significantly improved the left ventricular developed pressure (94.0±4.7 vs. 69.0±6.5 mmHg, P&lt;0.05), decreased infarct size % (35.0±4.2 vs. 16.0±2.5, P&lt;0.05), decreased superoxide generation and nitrotyrosine production. Conclusions: These findings demonstrate that SFZ may provide potent cardioprotection by attenuating post-ischemic ROS and RNS generation, and could serve as an attractive adjuvant therapy in the clinical setting of myocardial I/R injury.

Implication of Ischemia-Reperfusion in the Development of Acute Lung Injury (Review)

The review considers a role of ischemia-reperfusion in the pathogenesis of acute lung injury (ALI) and presents data on the experimental models of ischemia-reperfusion in the lung and its resistance to ischemia. It also demonstrated the leading role of systemic inflammatory reaction in the pathogenesis of ALI in ischemia-reperfusion. ALI is shown to occur in spontaneous ischemia-reperfusion of both the lung (lung transplantation, extracorporeal circulation) and other organs, such as the intestine, liver, and lower limbs.

Alleviation of ischemia-reperfusion injury in rat liver transplantation by induction of small interference RNA targeting Fas

Cellular apoptosis plays an important role in ischemia-reperfusion (I/R) injury during organ transplantation. Synthetic small interference RNA (siRNA) targeting apoptotic receptor Fas has proven effective to protect mice against hepatitis and renal I/R injury. The objective of this study is to investigate the silencing impact of Fas siRNA to alleviate I/R injury in rat liver transplantation. Rat hepatocytes (BRL cells) were transfected with three pairs of synthesized Fas siRNA; cells untreated and treated with GFP siRNA were taken as blank and siRNA control. The most effective Fas siRNA was chosen for in vivo experiments. Syngeneic orthotopic liver transplantation was performed in Fas siRNA group, siRNA control group, and blank control group of Sprague-Dawley rats. There were 25 pairs of rats in each group. siRNA transfection of donor rats was done with hydrodynamic injection method 48 h before liver procurement. Blood and liver samples were collected for evaluation of serum ALT levels, Fas protein and mRNA expression, and apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, 1, 3, 6, 12, and 24 h after liver transplantation. Fas siRNA2, which inhibited Fas gene expression much more than other siRNAs, was chosen for in vivo experiment. The serum ALT levels of Fas siRNA group were much less than those of blank and siRNA control groups 1, 3, 6, 12, and 24 h after blood reperfusion, indicating diminishing ischemia-reperfusion injury. Donor livers in Fas siRNA group had substantially less cell apoptosis. The expression of Fas mRNA and protein was reduced dramatically in the Fas siRNA group compared with the other two groups. Fas-mediated apoptosis play an important role in I/R injury of rat liver transplantation. Silencing Fas by hydrodynamic injection of siRNA holds therapeutic promise to limit I/R injury.

Protective Effect of Diltiazem on Hepatic Ischemia-Reperfusion Injury in Rats by Improving Liver Tissue Blood Flow

Background Cytosolic calcium ions are known to play an important role in ischemia-reperfusion (IR) injury. However, the protective effect of calcium channel blockers remains controversial in liver IR injury. Moreover, calcium channel blockers improve hepatic IR injury not due to blocking an increase in hepatic calcium concentration. Therefore, we hypothesized that calcium antagonists protected a liver from IR injury by a vasodilatory action rather than by the inhibition of an increase in Ca 2+ within parenchymal cells. This study evaluated the effects of diltiazem, a calcium channel blocker, on liver energy metabolism and blood flow after IR injury. Methods Twenty-seven rats underwent hepatic ischemia for 30 minutes followed by 60 minutes of reperfusion. The animals were allocated into group C (without drug); group D5 (diltiazem, 5 μg/kg per min); or group D10 (diltiazem, 10 μg/kg per min). Diltiazem was infused before laparotomy and then throughout the experiment. Results After 60 minutes of reperfusion, liver tissue blood flow and ATP concentrations were significantly higher in group D10 than the other animals (both, P < .05). Changes in ATP values strongly correlated those observed in blood flow (R = 0.80, P < .001). Conclusion Diltiazem improved ATP-generating capacity during reperfusion by improving liver tissue blood flow. An improvement in hepatic tissue perfusion may be a therapeutic strategy for liver IR injury.

Expression of toll-like receptor 4 and MD-2 gene and protein in Kupffer cells after ischemia-reperfusion in rat liver graft.

To investigate the expression of toll-like receptor 4 (TLR4) and MD-2 gene and protein in Kupffer cells (KCs) and their role in ischemia-reperfusion (IR) injury of rat liver graft. KCs were isolated at 0 (control group), 2, 12, 24 h (IR group) following IR in rat liver graft. mRNA expression of TLR4 and MD-2 was detected by RT-PCR analysis, protein expression of TLR4/MD-2 was detected by flow cytometric (FCM) analysis, and tumor necrosis factor-alpha (TNF-alpha) level in supernatant was measured by ELISA. Then isolated KCs were incubated with anti-TLR4 polyclonal antibody (anti-TLR4 group), and TNF-alpha level was measured again. The mRNA and protein expression of TLR4/MD-2 and the level of TNF-alpha in IR group increased significantly at 2 h following IR, and reached the maximum at 12 h, and slightly decreased at 24 h, but were still significantly higher than those in the control group (P<0.01). The expression of these factors was markedly decreased after anti-TLR4 antibody treatment as compared with the IR group (P<0.01). Lipopolysaccharide (LPS) following IR can up-regulate TLR4/MD-2 gene and protein expression in KCs, and synthesize cytokine TNF-alpha. Anti TLR4 antibody can inhibit the production of TNF-alpha induced by LPS. TLR4 and its partner molecule MD-2 may play an important role in Kupffer cell activation and IR injury.

AT(1) and AT(2) receptor expression and blockade after acute ischemia-reperfusion in isolated working rat hearts.

We assessed ANG II type 1 (AT(1)) and type 2 (AT(2)) receptor (R) expression and functional recovery after ischemia-reperfusion with or without AT(1)R/AT(2)R blockade in isolated working rat hearts. Groups of six hearts were subjected to global ischemia (30 min) followed by reperfusion (30 min) and exposed to no drug and no ischemia-reperfusion (control), ischemia-reperfusion and no drug, and ischemia-reperfusion with losartan (an AT(1)R antagonist; 1 micromol/l), PD-123319 (an AT(2)R antagonist; 0.3 micromol/l), N(6)-cyclohexyladenosine (CHA, a cardioprotective adenosine A(1) receptor agonist; 0.5 micromol/l as positive control), enalaprilat (an ANG-converting enzyme inhibitor; 1 micromol/l), PD-123319 + losartan, ANG II (1 nmol/l), or ANG II + losartan. Compared with controls, ischemia-reperfusion decreased AT(2)R protein (Western immunoblots) and mRNA (Northern immunoblots, RT-PCR) and impaired functional recovery. PD-123319 increased AT(2)R protein and mRNA and improved functional recovery. Losartan increased AT(1)R mRNA (but not AT(1)R/AT(2)R protein) and impaired recovery. Other groups (except CHA) did not improve recovery. The results suggest that, in isolated working hearts, AT(2)R plays a significant role in ischemia-reperfusion and AT(2)R blockade induces increased AT(2)R protein and cardioprotection.

Ischemia-reperfusion injury is associated with inflammatory cell infiltration: evaluation in a pig kidney autotransplant model

DAMAGE sustained by the allograft during the process of transplantation has been shown to be influenced by cold ischemia-reperfusion injury, which is one of the principal “antigen-independent” factors. A previous study demonstrated that tissue injury occurs within isografts as compared to allografts, in the absence of alloantigen stimulation. In a rat model, a recent report suggests that molecules involved in T-cell costimulation may play a key role in ischemia-reperfusion in the kidney, independent of any alloimmune stimuli. The aim of this study was to assess the effect of the length of cold ischemic time in an autotransplant pig kidney model on delayed graft function and inflammatory cell infiltration.

Alveolar recruitment prevents rapid-reperfusion–induced injury of lung transplants

Background: Physical factors play an important role in ischemia-reperfusion–induced injury of lung transplants. For example, rapid restoration of reperfusion resulted in severe pulmonary edema and deterioration of pulmonary function of lung explants in an ex vivo reperfusion system. This type of injury can be prevented by a stepwise increase in the perfusion flow rate, or by adding prostaglandin E 1 (PGE 1) to the blood perfusate during the first 10 minutes. However, the mechanisms of these protective effects are unknown. We noted a dramatic decrease in airway pressure rather than pulmonary arterial pressure in these studies, suggesting that lung recruitment may be an important factor in minimizing injury. Methods In the present study, we examined the importance of alveolar recruitment in preventing rapid-reperfusion–induced lung injury. Rat lungs were flushed preserved with low potassium dextran solution for 12 hours at 4°C. Lung explants were randomly divided into three groups: 1) untreated control; 2) lungs inflated to total lung capacity for 2 minutes; and 3) lungs ventilated for 10 minutes prior to reperfusion. Postpreservation lung function was assessed in an isolated rat lung reperfusion model. Results Rapid initiation of reperfusion led to severe pulmonary edema and significant pulmonary dysfunction. In inflation or ventilation groups, the injury was significantly attenuated. The Pa O 2 and shunt fractions in these lungs were comparable to normal lungs. A significant drop in airway pressure was observed in these two groups and the lung compliance in the inflation group was significantly better than other two groups. Conclusions These results suggest that overcoming alveolar collapse with inflation or ventilation, may protect the lung from mechanical-stress–induced injury during reperfusion.

Protective effect of tnf-α and il-1β inhibitor fr167653 on ischemia-reperfusion injury in rat small intestinal transplantation

RECENTLY, it has been demonstrated that the proinflammatory cytokines such as tumor necrosis factor (TNF) and interleukin (IL)-1 may play an important role in ischemia-reperfusion (I-R) injury in several organs such as the liver, lung, kidney, heart, and small intestine, both in nontransplant and in transplant experimental models,1,2 as well as in clinical transplant cases.3 A newly developed agent, {type:entrez-nucleotide,attrs:{text:FR167653,term_id:258093044,term_text:FR167653}}FR167653 (FR), has recently been shown to have potent specific inhibitory effects on TNF-α and IL-1β activity in vitro and in vivo. In this study, we investigated the protective effect of FR on I-R injury of intestinal grafts as well as remote organs such as liver, kidney, and lung in a rat transplantation model.

Complement-mediated lung injury and neutrophil retention after intestinal ischemia-reperfusion.

Complement-mediated neutrophil activation appears to play an important role in ischemia-reperfusion (I/R) injury in a variety of tissues, including the heart, lung, and small bowel. The objective of this study was to determine whether inhibition of the alternative and classic complement cascades by administration of soluble complement receptor 1 (sCR1) prevents the increased neutrophil stiffness, lung neutrophil retention, and pulmonary microvascular injury elicited by a systemic inflammatory insult. Isolated lungs were perfused with blood obtained from animals subjected to 2 h of intestinal ischemia and 20 min of reperfusion (I/R) or control (nonischemic) surgery. Intestinal I/R resulted in a significant increase in neutrophil stiffness, lung neutrophil retention, and increased pulmonary microvascular permeability, effects that were prevented by administration of sCR1 before intestinal reperfusion. The results of this study suggest that I/R injury in the gut is a potent systemic inflammatory stimulus that induces complement-mediated neutrophil stiffness, lung neutrophil entrapment, and pulmonary microvascular dysfunction.

Detection of nitric oxide production and its role in pancreatic ischemia-reperfusion in rats.

Partial ischemia of rat pancreas body and tail was obtained by occlusion of the celiac axis for 1 h after gastrectomy. The plasma level of nitrite plus nitrate in both systemic and portal venous blood after reperfusion was significantly higher than that after sham operation and ischemia alone. The elevation after reperfusion was significantly decreased by NG-nitro-L-arginine methyl ester (L-NAME). Simultaneous administration of L-arginine counteracted the L-NAME-induced decrease in the level of nitric oxide (NO) end products. Generation of NO was further demonstrated by nitrosylhemoglobin detection by electron spin resonance in the blood after reperfusion. On the other hand, the plasma level of lipase, a marker of damage to pancreatic exocrine tissue, was significantly increased after ischemia-reperfusion and further increased by administration of L-NAME. This increase in lipase correlated with a decrease in tissue blood flow in the pancreas. These results suggest that NO is generated during and may have a protective role in ischemia-reperfusion of the rat pancreas.