Protective effect of lipopolysaccharide preconditioning in hepatic ischaemia reperfusion injury

Background

Preconditioning using lipopolysaccharide (LPS), a toll-like receptor 4 (TLR4) ligand, has been demonstrated to reduce ischaemia/reperfusion injury (IRI) in some organs, but its effect in the liver has not been elucidated. We examined the liver protective mechanism and correlated signalling pathway of LPS preconditioning in mice.

Methods

BALB/c and TLR4 mutant mice underwent 90 min of 70% hepatic ischaemia. Lipopolysaccharide (100 µg/kg) was injected intraperitoneally 20 h or 30 min before ischaemia. Liver damage after reperfusion was examined using serum samples and liver specimens. To analyse the mechanism of preconditioning in detail, phosphorylation of representative signalling mediators to nuclear factor-κB (NF-κB) activation, Akt and interleukin-1 receptor-associated kinase-1 (IRAK-1), and expression of a negative feedback inhibitor, suppressor of cytokine signalling-1 (SOCS-1), were evaluated by Western blotting.

Results

Pretreatment with LPS only 20 h before ischaemia elicited a preconditioning effect; however, preconditioning was absent in TLR4 mutant mice. Lipopolysaccharide significantly decreased serum alanine aminotransferase, tumour necrosis factor-α, hepatocyte necrosis and NF-κB activity after reperfusion. Phosphorylated IRAK-1 was suppressed by LPS, whereas no difference was observed in phosphorylated Akt. Pre-ischaemic LPS provided early induction of SOCS-1.

Discussion

Late-phase LPS preconditioning provided liver protection against IRI through the downregulation of the TLR4 cascade derived from early induction of SOCS-1 during ischaemia/reperfusion.     

Ischaemic preconditioning of the graft in adult living related right lobe liver transplantation: impact on ischaemia�Creperfusion injury and clinical relevance

Background

Ischaemic preconditioning (IPC) of the right liver graft in the donor has not been studied in adult-to-adult living related liver transplantation (LRLT).

Objective

To assess the IPC effect of the graft on ischaemia reperfusion injury in the recipient and compare recipient and donor outcomes with and without preconditioned grafts.

Patients and methods

Alternate patients were transplanted with right lobe grafts that were (n =22; Group _Precond) or were not (n =22; Group _Control) subjected to IPC in the living donor. Liver ischaemia–reperfusion injury, liver/kidney function, morbidity/mortality rates and outcomes were compared. Univariate and multivariate analyses were performed to identify factors predictive of the aspartate aminotransferase (AST) peak and minimum prothrombin time.

Results

Both groups had similar length of hospital stay, morbidity/mortality, primary non-function and acute rejection rates. Post-operative AST (P =0.8) and alanine aminotransferase (ALT) peaks (P =0.6) were similar in both groups (307 ± 189 and 437 ± 302 vs. 290 ± 146 and 496 ± 343, respectively). In univariate analysis, only pre-operative AST and warm ischemia time (WIT) were significantly associated with post-operative AST peak (in recipients). In multivariate analysis, the graft/recipient weight ratio (P =0.003) and pre-operative bilirubin concentration (P =0.004) were significantly predictive of minimum prothrombin time post-transplantation.

Conclusions

Graft IPC in the living related donor is not associated with any benefit for the recipient or the donor and its clinical value remains uncertain.     

The effect of Ligustrum delavayanum on isolated perfused rat heart

BACKGROUND:

Extract of ligustrum leaves (Ligustrum delavayanum Hariot [Oleaceae]) is well known in traditional Chinese medicine. One of the active components, oleuropein, displays vasodilating and hypotensive effects.

OBJECTIVE:

To analyze the effect of 0.008% lyophilized extract of ligustrum dissolved in 0.5% ethanol on heart function.

ANIMALS AND METHODS:

Experiments were done on isolated rat hearts perfused by the Langendorff method in control conditions and during ischemic-reperfusion injury.

RESULTS:

Application of ligustrum induced positive inotropic and vasodilating effects in spontaneously beating hearts. Pretreatment of the hearts with ligustrum reduced left ventricular diastolic pressure measured during reperfusion and improved left ventricular contraction compared with hearts without any pretreatment. Ligustrum significantly suppressed the incidence and duration of cardiac reperfusion arrhythmias, expressed as G-score, from 7.40±0.58 in nontreated rats to 1.97±0.50.

DISCUSSION:

Application of ligustrum or ethanol alone induced changes in coordination between atria and ventricles during ischemia-reperfusion injury. The ‘g-score’, a new parameter summing the incidence and duration of atrioventricular blocks, atrioventricular dissociation and cardiac arrest, is introduced. The g-scores with ligustrum pretreatment were higher during ischemia than during reperfusion. Ethanol significantly depressed myocardial contractility and coronary flow, and nonsignificantly decreased heart rate of isolated rat hearts. Electrical changes observed during coronary reperfusion in the presence of ethanol were accompanied by deterioration of contractile function.

CONCLUSIONS:

Ligustrum had a significant protective effect on rat myocardium against ischemic-reperfusion injury. Ethanol partially attenuated the protective effect of ligustrum.     

Substrate-dependent modulation of oxidative phosphorylation in isolated mitochondria following in vitro hypoxia and reoxygenation injury

BACKGROUND/OBJECTIVES:

Previous studies using isolated mitochondria have provided new insight into the mechanisms and interventions for ischemia and reperfusion (I/R) injury. In in vitro experiments involving isolated mitochondria, hypoxia and reoxygenation (H/R) has been widely used to mimic I/R injury. However, in in vitro H/R mitochondrial experiments, the effects of various substrates on mitochondrial oxidative phosphorylation are unclear. In the present study, the effects of in vitro I/R injury on mitochondrial oxidative phosphorylation under different substrate conditions were investigated.

METHODS:

Hypoxia was achieved following complete consumption of oxygen by mitochondria isolated from rat heart tissue in an experimental chamber. The H/R protocol involved 30 min hypoxia followed by 15 min reoxygenation in a chamber opened to the atmosphere. Mitochondrial respiration and respiratory control ratio (RCR) were measured.

RESULTS:

When pyruvate/malate were used as substrates, H/R significantly decreased state 3 respiration (28.2±12 nmol O₂/min/mg protein) and RCR (2.7±0.8) compared with the control (121.4±32.5 nmol O₂/mg protein/min and 7.8±1.2, respectively). In contrast, when succinate was used without rotenone, H/R significantly increased state 3 respiration (57.0±11.2 nmol O₂/mg protein/min) and RCR (2.0±0.3) compared with the control (48.2±12.3 nmol O₂/mg protein/min and 1.3±0.2, respectively).

CONCLUSIONS:

The present study demonstrated that mitochondrial oxidative phosphorylation can be modulated by H/R in vitro depending on substrate conditions.     

Hyperbaric oxygen therapy reduces the severity of ischaemia, preservation and reperfusion injury in a rat model of liver transplantation

Background

Approaches to increase organ availability for orthotopic liver transplantation (OLT) often result in the procurement of marginal livers that are more susceptible to ischaemia, preservation and reperfusion injury (IPRI).

Methods

The effects of post-OLT hyperbaric oxygen (HBO) therapy on IPRI in a syngeneic rat OLT model were examined at various time-points. The effects of IPRI and HBO on hepatocyte necrosis, apoptosis, proliferation, and sinusoidal morphology and ultrastructure were assessed.

Results

Post-OLT HBO therapy significantly reduced the severity of IPRI; both apoptosis [at 12 h: 6.4 ± 0.4% in controls vs. 1.6 ± 0.7% in the HBO treatment group (p < 0.001); at 48 h: 2.4 ± 0.2% in controls vs. 0.4 ± 0.1% in the HBO treatment group (p < 0.001)] and necrosis [at 12 h: 18.7 ± 1.8% in controls vs. 2.4 ± 0.4% in the HBO treatment group (p < 0.001); at 48 h: 8.5 ± 1.3% in controls vs. 3.4 ± 0.9% in the HBO treatment group (P = 0.019)] were decreased. Serum alanine transaminase was reduced [at 12 h: 1068 ± 920 IU/l in controls vs. 370 ± 63 IU/l in the HBO treatment group (P = 0.030); at 48 h: 573 ± 261 IU/l in controls vs. 160 ± 10 IU/l in the HBO treatment group (P = 0.029)]. Treatment with HBO also promoted liver regeneration [proliferation at 12 h: 4.5 ± 0.1% in controls vs. 1.0 ± 0.3% in the HBO treatment group (p < 0.001); at 48 h: 8.6 ± 0.7% in controls vs. 2.9 ± 0.2% in the HBO treatment group (p < 0.01)] and improved sinusoidal diameter and microvascular density index.

Conclusions

Hyperbaric oxygen therapy has persistent positive effects post-OLT that may potentially transfer into clinical practice.     

Liver grafts from selected older donors do not have significantly more ischaemia reperfusion injury

Background

There is a general concern that aged organs are more susceptible to ischaemia. In the light of recent proposals to change the liver allocation system by expanding regional sharing, it is feared that increased cold ischaemia time of grafts from older donors may reduce graft survival. The aim of this study was to correlate donor age and the patterns of ischaemia reperfusion injury and synthetic function early after liver transplantation.

Methods

We performed a retrospective study of first transplants using a single-centre electronic database. Patterns of liver injury (based on transaminases and post-reperfusion biopsy), synthetic function (international normalized ratio [INR]), and graft and patient survival in recipients receiving liver grafts from donors aged ≥65 years (group 1, n= 50) were compared with equivalent patterns in a matched cohort of recipients transplanted with grafts from donors aged <65 years (group 2, n= 50).

Results

There was no significant difference in transaminase levels from day 0 to day 6 after transplantation. When groups 1 and 2 were subdivided into two subgroups based on the duration of graft cold ischaemia time (<8 h and ≥8 h), there was no statistical difference in transaminase levels during the first 7 days. There were two cases (4%) of primary non-function in group 1 and one (2%) in group 2. Initial poor function did not differ significantly between the groups (26% vs. 24%; P= 0.81). In addition, there was no difference in histological changes in post-reperfusion biopsies (21% vs. 34%; P= 0.078) and rate of acute rejection episodes in the first year (30% vs. 32%; P= 0.99). There was no significant difference between groups 1 and 2 in 1-year patient and graft survivals (78% vs. 90% [P= 0.17]; 88% vs. 94% [P= 0.48], respectively).

Conclusions

Judiciously selected livers from aged donors are not associated with major increased susceptibility to ischaemia reperfusion injury.     

Effects of Ischemic Postconditioning on the Hemodynamic Parameters and Heart Nitric Oxide Levels of Hypothyroid Rats

Background

Ischemic postconditioning (IPost) is a method of protecting the heart against ischemia-reperfusion (IR) injury. However, the effectiveness of IPost in cases of ischemic heart disease accompanied by co-morbidities such as hypothyroidism remains unclear.

Objective

The aim of this study was to determine the effect of IPost on myocardial IR injury in hypothyroid male rats.

Methods

Propylthiouracil in drinking water (500 mg/L) was administered to male rats for 21 days to induce hypothyroidism. The hearts from control and hypothyroid rats were perfused in a Langendorff apparatus and exposed to 30 min of global ischemia, followed by 120 min of reperfusion. IPost was induced immediately following ischemia.

Results

Hypothyroidism and IPost significantly improved the left ventricular developed pressure (LVDP) and peak rates of positive and negative changes in left ventricular pressure (±dp/dt) during reperfusion in control rats (p < 0.05). However, IPost had no add-on effect on the recovery of LVDP and ±dp/dt in hypothyroid rats. Furthermore, hypothyroidism significantly decreased the basal NO metabolite (NO_x) levels of the serum (72.5 ± 4.2 vs. 102.8 ± 3.7 μmol/L; p < 0.05) and heart (7.9 ± 1.6 vs. 18.8 ± 3.2 μmol/L; p < 0.05). Heart NO_x concentration in the hypothyroid groups did not change after IR and IPost, whereas these were significantly (p < 0.05) higher and lower after IR and IPost, respectively, in the control groups.

Conclusion

Hypothyroidism protects the heart from IR injury, which may be due to a decrease in basal nitric oxide (NO) levels in the serum and heart and a decrease in NO after IR. IPost did not decrease the NO level and did not provide further cardioprotection in the hypothyroid group.     

Effect of a neutrophil elastase inhibitor on ventilator-induced lung injury in rats

Objective

We hypothesized that pretreatment with sivelestat therapy could attenuate ventilator-induced lung injury (VILI) and lung inflammation in a rat model.

Methods

The neutrophil elastase inhibitor was administered intraperitoneally 30 min before and at the initiation of ventilation. The rats were categorized as (I) sham group; (II) VILI group; (III) sivelestat group; (IV) early sivelestat group. Wet-to-dry weight ratio, bronchoalveolar lavage fluid (BALF) neutrophil and protein, tissue malondialdehyde (MDA) and histologic VILI scores were investigated.

Results

The ratio of wet-to-dry weight, BALF neutrophil and protein, tissue MDA and VILI scores were significantly increased in the VILI group compared to the sham group [3.85±0.32 vs. 9.05±1.02, P<0.001; (0.89±0.93)×10⁴ vs. (7.67±1.41)×10⁴ cells/mL, P<0.001; 2.34±0.47 vs. 23.01±3.96 mg/mL, P<0.001; 14.43±1.01 vs. 36.56±5.45 nmol/mg protein, P<0.001; 3.78±0.67 vs. 7.00±1.41, P<0.001]. This increase was attenuated in the early sivelestat group compared with the sivelestat group [wet-to-dry ratio: 6.76±2.01 vs. 7.39±0.32, P=0.032; BALF neutrophil: (5.56±1.13)×10⁴ vs. (3.89±1.05)×10⁴ cells/mL, P=0.021; BALF protein: 15.57±2.32 vs. 18.38±2.00 mg/mL, P=0.024; tissue MDA: 29.16±3.01 vs. 26.31±2.58, P=0.049; VILI scores: 6.33±1.41 vs. 5.00±0.50, P=0.024].

Conclusions

Pretreatment with a neutrophil elastase inhibitor attenuates VILI in a rat model.     

The effect of mebudipine on cardiac function and activity of the myocardial nitric oxide system in ischaemia–reperfusion injury in rats

Objectives

Previous studies have suggested that failure of the synthesis of nitric oxide is involved in the pathophysiology of myocardial ischaemia–reperfusion injury. In this study, we investigated the effect of mebudipine, a new dihydropyridine calcium channel blocker, on cardiac function and activity of the myocardial nitric oxide system in ischaemia–reperfusion injury in isolated rat hearts.

Methods

Forty male Wistar rats (250–300 g) were divided into four groups (n = 10): sham, control, vehicle and drug groups. The animals were anesthetised with sodium pentobarbital (6 mg/kg intraperitoneal). The hearts were quickly removed, mounted on a Longendorff apparatus and perfused with Krebs-Henseleit solution under constant pressure at 37°C. After 20 min stabilisation period, the ischaemic groups received 30 min global ischaemia and 120 min reperfusion. For the drug and vehicle groups, before ischaemia the hearts were perfused with mebudipine (10^-3 µM) or ethanol-enriched solution (0.01%) for 25 min, respectively. Myocardial function, and creatine kinase, lactate dehydogenase and total nitric oxide metabolite (nitrite and nitrate) levels were analysed.

Results

Cardiac functions had recovered significantly in the mebudipine group (p < 0.01). Furthermore, mebudipine remarkably reduced the levels of lactate dehydogenase and creatine kinase in the coronary effluent and increased myocardial nitric oxide metabolite levels compared with the control group.

Conclusion

Our results indicate that mebudipine reduced the intensity of myocardial ischaemia–reperfusion injury, and that activation of the myocardial nitric oxide system played an important role in this regard.     

Osteogenic protein-1 reduces intercellular adhesion molecule-1 messenger RNA expression,infarct size and TUNEL-positive cardiomyocytes in ischemia/reperfusion rat hearts

BACKGROUND:

Osteogenic protein, a member of the transforming growth factor-beta superfamily, has been reported to decrease the expression of intercellular adhesive molecules and prevent neutrophil accumulation and activity in tissue injury.

OBJECTIVE:

To examine the effects of osteogenic protein on ischemia/reperfusion in rat hearts.

METHODS:

Reperfusion was established after a 90 min ligation of the proximal left coronary artery in rats. Recombinant human osteogenic protein-1 (200 μg/kg) was administered via the femoral vein just before reperfusion. Intercellular adhesion molecule-1 (ICAM-1) messenger RNA (mRNA) expression and infarct size were evaluated using Northern blotting and triphenyl tetrazolium chloride staining, respectively. Terminal deoxynucleotidyl transferase mediated biotin-16-2′-deoxyuridine-5′-triphosphate nick end labeling (TUNEL) staining was also performed.

RESULTS:

In osteogenic protein-1 treated rats, the expression of ICAM-1 mRNA in ischemia/reperfusion hearts rapidly increased 4 h after reperfusion, although, the increase was lower than that observed in the vehicle-treated hearts (7.4±1.6-fold versus 14.6±3.7-fold increase compared to the increase observed in preligation control hearts, respectively). Similarly, in day 1 and day 7 hearts, the increase in ICAM-1 mRNA expression was significantly lower in ischemia/reperfusion hearts from rats treated with osteogenic protein-1 than in vehicle-treated rats (2.5±0.1-fold versus 5.8±2.3-fold and 1.5±0.3-fold versus 3.5±0.2-fold, respectively). Infarct size in rats treated with osteogenic protein-1 was significantly smaller than that observed in rats treated with vehicle (13.1±1.2% versus 28.5±5.7% of the left ventricle, P<0.01). The percentage of TUNEL-positive cardiomyocytes in ischemia/reperfusion hearts in rats treated with osteogenic protein-1 was significantly lower than in rats treated with vehicle (17.1±5.3% versus 31.1±4.5%, P<0.01).

CONCLUSION:

The present study demonstrated that recombinant human osteogenic protein-1 suppressed ICAM-1 mRNA expression, reduced infarct size and decreased TUNEL-positive cardiomyocytes in ischemic/reperfused rat hearts.     

Mechanical ventilation modulates Toll-like receptors 2, 4, and 9 on alveolar macrophages in a ventilator-induced lung injury model

Objective

To investigate the role of Toll-like receptor 2 (TLR2), TLR4, TLR9 and myeloid differentiation factor 88 (MyD88) on alveolar macrophages in ventilator-induced lung injury (VILI).

Methods

Male, adult pathogen-free Sprague-Dawley rats weighing 300-350 g were used in this study. Animals were tracheotomized and allowed to breathe spontaneously for 4 h or mechanically ventilated for 4 h with low or high tidal volume (7 or 40 mL/kg). TLR2, TLR4, and TLR9, MyD-88 and NF-κΒ of alveolar macrophages’ expression under the different ventilation conditions were detected. Pulmonary permeability, lung inflammatory, IL-6 and IL-1β were assessed as well.

Results

Rats subjected to high tidal volume showed significantly greater pulmonary permeability and lung inflammatory than the control rats. Alveolar macrophages from rats subjected to high tidal volume also showed significantly higher protein expression of TLR2 (0.59±0.049 vs. 0.35±0.036 and 0.36±0.031, both P<0.001), TLR4 (0.845±0.0395 vs. 0.401±0.026 and 0.403±0.020, both P<0.001), TLR9 (0.727±0.074 vs. 0.383±0.039 and 0.367±0.043, both P<0.001), MyD-88 (1.01±0.060 vs. 0.485±0.045 and 0.507±0.046, both P<0.001) and NF-κΒ (0.776±0.067 vs. 0.448±0.043 and 0.481±0.047, both P<0.001), as well as significantly higher concentrations of IL-6 (7.32±0.24 vs. 2.42±0.13 and 2.44±0.32, both P<0.001) and IL-1β (139.95±9.37 vs. 53.63±5.26 and 53.55±6.63, both P<0.001) than the control and low tidal volume group.

Conclusions

The overexpression of TLR2, TLR4, and TLR9 on alveolar macrophages and release of pro-inflammatory cytokines play a role in VILI.     

Pulmonary function assessment in the early phase of patients with smoke inhalation injury from fire

Objectives

Fire smoke contains toxic gases and numerous chemical compounds produced by incomplete combustion, and may cause injury to the airways. Increased airway reactivity, as well as a decrease in lung function, has been reported as a sequela of smoke inhalation injury. This study was undertaken to assess lung functions in the early phase of patients with smoke inhalation damage from fires.

Methods

A total of 15 patients with fire smoke inhalation (fire smoke group) and 15 subjects with chronic cough but no previous history of lung disease (chronic cough group) were enrolled. For diagnosis of inhalation injury, we performed bronchoscopy, high-resolution computed tomography (HRCT), as well as arterial carboxyhemoglobin (COHb) at admission. Clinical characteristics, pulmonary function tests (PFTs) and mannitol bronchial provocation tests (BPTs) were analyzed and compared between the two groups.

Results

In fire smoke group, initial COHb levels and the PaO₂/FiO₂ ratio were (14.8±18.49)% and 425.7±123.68, respectively. Of seven patients performing HRCT, 4 (57.1%) showed the CT findings compatible with lung involvement of inhalation injury. Post bronchodilator value of the percent of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV₁) were (76.0±24.27)% and (79.8±27.82)%, respectively. Pre-and post- bronchodilator forced expiratory flow between 25% and 75% of the FVC (FEF_25-75) and the percent predicted FEF_25-75 were 2.41±1.47 vs. 2.65±1.45 L (P=0.045), and (68.7±37.29)% vs. (76.4±36.70)% (P=0.031), respectively. Two patients (13.3%) had positive bronchodilator response (BDR). In fire smoke and chronic cough group, all the subjects showed mannitol BPTs within normal limits.

Conclusions

Fire smoke inhalation leads to mild obstructive small airway disease pattern of pulmonary function in the early phase of patients with fire smoke damage. Further studies, however, need to be followed to identify the relationship between airway narrowing to inhaled mannitol and smoke inhalation injury.     

Expression of genes involved in rat liver angiogenesis after ischaemia and reperfusion: effects of ischaemic pre- and post-conditioning

Background

During surgery, ischaemic pre- (IPC) and post-conditioning (IPO) protects the liver against ischaemia/reperfusion injuries (I/R-injuries). The impact of ischaemic conditioning on liver regeneration has been less well studied. Angiogenesis is an important part of liver regeneration after hepatectomy. The aim of the present study was to investigate the effect of ischaemia/reperfusion and ischaemic conditioning on the expression of genes with angiogenic potential in a model of rat liver ischaemia.

Methods

A model of total liver ischaemia (30 min) and reperfusion (30 min) was employed using Wistar rats. Rats were randomized into five groups: (C) control (IRI) ischaemic, IPC, IPO and IPC + IPO. Liver enzymes were sampled at the end of reperfusion. Liver biopsies were analysed using cDNA microarrays.

Results

Alanine aminotransferase (ALT) increased significantly in all the ischaemic groups compared with controls (P = 0.000). Searching databases 99 genes involved in rat liver angiogenesis were identified. Compared with group (C) the number of genes significantly up-regulated was as follows: IRI (n = 5), IPC (n = 24), IPO (n = 33) and IPC + IPO (n = 18). No genes were down-regulated in the four groups compared with controls.

Conclusion

Ischaemic conditioning, as demonstrated in the present study, seems to be potent activators of angiogenic genes. This might be favourable to the regenerating liver.     

Effects of intravenous administration of pentoxifylline in pancreatic ischaemia–reperfusion injury

Background

Therapeutic strategies to reduce the occurrence of pancreatic ischaemia–reperfusion (I–R) injury might improve outcomes in human pancreas and kidney transplantation. In addition to its haemorrheologic effects, pentoxifylline has an anti-inflammatory effect by inhibiting NF-κB activation. This group has previously demonstrated that pentoxifylline induces an anti-inflammatory response in acute pancreatitis and liver I–R models. This led to the hypothesis that pentoxifylline might reduce pancreatic and renal lesions and the systemic inflammatory response in pancreatic I–R injury. The aim of this experimental study was to evaluate the effect of pentoxifylline administration in a rat model of pancreatic I–R injury.

Methods

Pancreatic I–R was performed in Wistar rats over 1 h by clamping the splenic vessels. The animals submitted to I–R were divided into two groups: Group 1 (n = 20, control) rats received saline solution administered i.v. at 45 min after ischaemia, and Group 2 (n = 20) rats received pentoxifylline (25 mg/kg) administered i.v. at 45 min after ischaemia. Blood samples were collected to enable the determination of amylase, creatinine, tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-10. Pancreatic malondialdehyde (MDA) content, pancreas histology and pulmonary myeloperoxidase (MPO) were also assessed.

Results

Significant reductions in serum TNF-α, IL-6 and IL-10 were observed in Group 2 compared with Group 1 (P < 0.05). No differences in pancreatic MDA content or serum amylase levels were observed between the two groups. The histologic score was significantly lower in pentoxifylline-treated animals, denoting less severe pancreatic histologic damage.

Conclusions

Pentoxifylline administration reduced the systemic inflammatory response, the pancreatic histological lesion and renal dysfunction in pancreatic I–R injury and may be a useful tool in pancreas and kidney transplantation.     

Effect of remote ischemic preconditioning on hepatic microcirculation and function in a rat model of hepatic ischemia reperfusion injury

Background:

Liver transplantation involves a period of ischemia and reperfusion to the graft which leads to primary non-function and dysfunction of the liver in 5–10% of cases. Remote ischemic preconditioning (RIPC) has been shown to reduce ischemia reperfusion injury (IRI) injury to the liver and increase hepatic blood flow. We hypothesized that RIPC may directly modulate hepatic microcirculation and have investigated this using intravital microscopy.

Methods:

A rat model of liver IRI was used with 45 min of partial hepatic ischemia (70%) followed by 3 h of reperfusion. Four groups of animals (Sham, IRI, RIPC+IRI, RIPC+Sham) were studied (n= 6, each group). Intravital microscopy was used to measure red blood cell (RBC) velocity, sinusoidal perfusion, sinusoidal flow and sinusoidal diameter. Neutrophil adhesion was assessed by rhodamine labeling of neutrophils and cell death using propidium iodide.

Results:

RIPC reduced the effects of IRI by significantly increasing red blood cell velocity, sinusoidal flow and sinusoidal perfusion along with decreased neutrophil adhesion and cell death.

Conclusions:

Using intravital microscopy, this study demonstrates that RIPC modulates hepatic microcirculation to reduce the effects of IRI. HO-1 may have a key role in the modulation of hepatic microcirculation and endothelial function.     

Edaravone reduces mitochondrial damage due to reperfusion injury following leg ischemia in rats

PURPOSE:

Free radicals have been implicated in reperfusion injury. It was shown that the free radical scavenger edaravone might suppress reperfusion injury in rat extremities. The present study aimed to elucidate how edaravone suppresses reperfusion injury, focusing on its effect on the mitochondrial structure and glycogen storage in the lower extremity muscles.

METHODS:

Sixteen male Lewis rats (mean [± SD] weight 497±32 g) were divided into two groups and injected with either 3.0 mg/kg of edaravone (edaravone group, n=8 rats) or the same dose of saline (control group, n=8 rats) into the peritoneal cavity. The rat reperfusion injury models were created by clamping the bilateral common femoral arteries for 5 h, then declamping. The muscles were harvested more than 5 h after the start of reperfusion. The mitochondrial damage, defined as mitochondrial swelling, was examined using a transmission electron microscope at ×30,000 original magnification (n=3 for each rat). Glycogen storage, defined as a positive periodic acid-Schiff stain area, was examined using computerized densitometry (n=5 sections for each rat).

RESULTS:

The mitochondria in the control group demonstrated marked swelling (mean mitochondrial size = 0.169±0.059 μm²). However, the mitochondria in the edaravone group had significantly less swelling (mean mitochondrial size = 0.102±0.036 μm²; P<0.01). The mean percentage of positive periodic acid-Schiff stain was also significantly higher in the edaravone group than in the control group (51.7±6.8% versus 7.3±2.1%; P<0.01).

CONCLUSION:

The results suggested that edaravone reduces mitochondrial damage due to reperfusion injury, resulting in a high level of glycogen storage.