Lower Limb Ischemia-reperfusion Injury Research Articles

Effects of sevoflurane and fullerenol C60 on lower limb ischemia-reperfusion injury in streptozocin-induced diabetic mice.

Ischemia-reperfusion injury (IRI) poses a significant challenge for physicians, necessitating the management of cell damage and the preservation of organ functions. Various surgical procedures, such as vascular surgery on extremities, temporary cross-clamping of the abdominal aorta in aortic surgery, and the use of a tourniquet in extremity surgeries, may induce lower limb IRI. The susceptibility to IRI is heightened in individuals with diabetes. This study aimed to investigate the effects of fullerenol C60 and sevoflurane on mouse muscle tissue in a lower limb IRI model and to assess their potential in preventing complications arising from ischemia-reperfusion in mice with streptozocin-induced diabetes. A total of 36 adult Swiss albino mice were randomly divided into six groups, each consisting of six mice: control group (group C), diabetes group (group D), diabetes-ischemia/reperfusion group (group DIR), diabetes-ischemia/reperfusion-fullerenol C60 group (group DIR-FC60), diabetes-ischemia/reperfusion-sevoflurane group (group DIR-S), and diabetes-ischemia/reperfusion-sevoflurane-fullerenol C60 group (DIR-S-FC60). Streptozocin (55 mg/kg) was intraperitoneally administered to induce diabetes in the relevant groups, with mice displaying blood glucose levels of 250 mg/dL or higher at 72 h were considered diabetic. After 4 weeks, all groups underwent laparotomy under anesthesia. In DIR-FC60 and DIR-S-FC60 groups, fullerenol C60 (100 mg/kg) was intraperitoneally administrated 30 min before the ischemia period. Sevoflurane, delivered in 100% oxygen at a rate of 2.3% and 4 L/min, was administered during the ischemia period in DIR-S and DIR-S-FC60 groups. In the IR groups, a microvascular clamp was placed on the infrarenal abdominal aorta for 120 min during the ischemia period, followed by the removal of the clamp and a 120-min reperfusion period. At the end of the reperfusion, gastrocnemius muscle tissues were removed for histopathological and biochemical parameter examinations. Histopathological examination revealed a significant reduction in the disorganization and degeneration of muscle cells in the DIR-S-FC60 group compared to the DIR group (p = 0.041). Inflammatory cell infiltration was notably lower in the DIR-S, DIR-FC60, and DIR-S-FC60 groups than in the DIR group (p = 0.031, p = 0.011, and p = 0.013, respectively). The total damage scores in the DIR-FC60 and DIR-S-FC60 groups were significantly lower than in the DIR group (p = 0.018 and p = 0.008, respectively). Furthermore, the levels of malondialdehyde (MDA) in the DIR-S, DIR-FC60, and DIR-S-FC60 groups were significantly lower than in the DIR group (p < 0.001, p < 0.001, and p < 0.001, respectively). Catalase (CAT) enzyme activity in the DIR-S, DIR-FC60, and DIR-S-FC60 groups was higher than in the DIR group (p = 0.001, p = 0.014, and p < 0.001, respectively). Superoxide dismutase (SOD) enzyme activity in the DIR-FC60 and DIR-S-FC60 groups was also higher than in the DIR group (p < 0.001 and p = 0.001, respectively). Our findings indicate that administering fullerenol C60 30 min prior to ischemia in diabetic mice, in combination with sevoflurane, led to a reduction in oxidative stress and the correction of IR-related damage in muscle tissue histopathology. We believe that the administration of fullerenol C60 before IR, coupled with sevoflurane administration during IR, exerts a protective effect in mice.

The Prevention of Ischemia-Reperfusion Injury in Elderly Rats after Lower Limb Tourniquet Use.

Background: Lower limb ischemia-reperfusion injury (IRI-LL) is a common major complication of orthopedic surgery, especially in elderly patients. It has previously been demonstrated that folinic acid (FA) reduced IRI-LL damage in 3–4-month-old rats. This current work analyses the effect of FA in the prevention of IRI-LL in elderly animals. Methods: Forty-two 18-month-old male WAG/RijHsd rats were subjected to 3 h of ischemia. Eighteen animals received FA (2.5 mg/kg, ip) 20 min before the end of the ischemia period, while the other half received the same volume of saline solution. The animals were sacrificed after 3 h, 24 h, and 14 days of reperfusion for biochemical (tissue damage markers and electrolytes), histopathological studies of the gastrocnemius muscle and the daily assessment of the limb function by the Rota Rod test, respectively. Results: The administration of FA prior to the end of the ischemia period reduced the increase in LDH and CK observed in non-treated animals by 30–40% (p < 0.0001). When the histological sections were analyzed, FA was found to have reduced the number of damaged muscle fibers per field by 20% (60 ± 17.1 vs. 80.7 ± 16.4, p < 0.0001). The functional test revealed that FA also led to an improvement in the muscle function, assessed by the length of time that the animals kept running on the rod, compared to untreated animals. Conclusions: The administration of FA, prior to the end of the ischemic period, decreases the damage induced by IRI-LL, also achieving a faster recovery of mobility.

Deep Learning Reconstruction Algorithm-Based MRI Image Evaluation of Edaravone in the Treatment of Lower Limb Ischemia-Reperfusion Injury.

This research aimed to evaluate the therapeutic effect of edaravone on lower limb ischemia-reperfusion injury by MRI images of graph patch-based directional curvelet transform (GPBDCT), compression reconstruction algorithm. 200 patients with lower limb ischemia-reperfusion injury after replantation of severed limb were randomly divided into the observation group (edaravone treatment) and control group (Mailuoning injection treatment), with 100 cases in each group. MRI scanning and image processing using the GPBDCT algorithm were used to evaluate the therapeutic effect of the two groups of patients. The results showed that the signal noise ratio (SNR) (22.01), relative l2 norm error (RLNE) (0.0792), and matching degree γ (0.9997) of the compression and reconstruction algorithm based on GPBDCT were superior to those of the conventional compression and reconstruction algorithm (P < 0.05). MRI examination showed that the decrease of bleeding signal after treatment in the observation group was superior to that in the control group. The levels of superoxide dismutase (SOD) (15 ± 2.02), malondialdehyde (MDA) (2.27 ± 1.02), B cell lymphoma-2 (Bcl-2) (8.5 ± 1.02), Bcl-2-associated X (Bax) (3.7 ± 0.42), and Caspase-3 protein (35.9 ± 5.42) in the observation group before and after treatment were significantly higher than those in the control group (P < 0.05). In conclusion, the GPBDCT-based compression reconstruction algorithm has a better effect on MRI image processing, and edaravone can better remove free radicals and alleviate apoptosis.

The Effect of Hydrogen-Rich Saline Solution on Erythrocyte Deformability in Lower Limb Ischemia Reperfusion Injury in Rats

The Effect of Hydrogen-Rich Saline Solution on Erythrocyte Deformability in Lower Limb Ischemia Reperfusion Injury in Rats

Effects of alpha-lipoic acid on skeletal muscle ischemia-reperfusion injury in mice

Aim: The main problem in the treatment of cardiovascular diseases, which is the most common cause of death in the world today, is reperfusion injury. In our study, we investigated the effects of alpha-lipoic acid on lower limb ischemia-reperfusion injury. Methods: In this study, 30 male Swiss breed albino mice weighing 45-65 g were used. Mice were randomly divided into 5 groups (Control group (C), Dimethyl Sulfoxide (DMSO) group, ischemia-reperfusion (IR) group, alpha-lipoic acid control group (ALA), alpha-lipoic acid - IR group (ALA+IR)), 6 mice in each group. All groups were administered 100 IU/kg intravenous heparin bolus 30 minutes before the procedure. Lower limb ischemia (2 hours) and reperfusion (2 hours) protocols were applied to the IR and ALA+IR groups by clamping the main femoral artery. Alpha-lipoic acid was administered to ALA and ALA+IR groups 1 hour before the experimental procedure (100 mg/kg intraperitoneal). After the experiment protocol, the lower limb gastrocnemius muscles were collected from the sacrificed mice and total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), Myeloperoxidase (MPO) and Malondialdehyde (MDA) levels were determined in the tissue. In addition, edema, necrosis, and inflammatory cell infiltration levels in the skeletal muscle were determined by histologic grading, and apoptosis was determined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method. Results: TAS measurements of ALA group subjects were higher than the control group (P=0.01). The TOS level of the ALA+IR group was lower than the IR group (P=0.01), but higher than the C, ALA, and DMSO groups. The OSI index of the IR group was significantly higher than the ALA+IR group (P=0.01). It was observed that the IR group was at higher levels than the ALA+IR group (P=0.01). MDA measurements of IR group subjects were higher than that of the C, ALA, DMSO, ALA+IR groups (P=0.01). Edema of the IR and ALA+IR group subjects were higher than the C, ALA, DMSO groups (P=0.01). Necrosis measurements of IR and ALA+IR group subjects were higher than C, ALA, DMSO groups (P=0.01). Inflammatory cell infiltration measurements of IR and ALA+IR group subjects were higher than C, ALA, DMSO groups (P=0.01). Apoptosis level was significantly lower in the ALA+IR group than in the IR group. (P=0.01). Conclusion: The results showed us that alpha-lipoic acid has a protective effect against oxidative damage, inflammation, and apoptosis in the tissue in lower limb ischemia-reperfusion.

The effect of fullerenol C60 on skeletal muscle after lower limb ischemia reperfusion injury in streptozotocin-induced diabetic rats

Aim: Fullerenol, a water-soluble C60-fullerene, has been demonstrated to scavenge free radicals in vitro and in vivo. The aim of the study was to investigate the effects of fullerenol C60 on lower skeletal muscles in a rat model of ischemia/reperfusion (I/R).Methods: After approval of the ethics committee, 30 Wistar Albino rat were divided into 5 groups with six animals per each as follows: Control (C), diabetes (D), diabetes+fullerenol C60 (DF), diabetes+I/R (group DIR) and diabetes I/R+fullerenol C60 (DIR-F) groups. Streptozotocin was administered to the rats to induce diabetes at a dose of 55 mg/kg. Four weeks after the onset of diabetes, rats were subjected to 2 hours of ischemia and 2 hours of reperfusion. At the end of the reperfusion period, skeletal muscle samples were taken from the lower extremity in all groups for histopathological and immunohistopathological examinations. Results: Myositis and endothelial caspase 3 enzyme activities were high in all groups, particularly DIR. Compared to C, DF and DIR-F groups, inflammation and myositis were significantly higher in the DIR group (P=0.001, P=0.006, P=0.001, respectively, and P=0.001, P=0.022, P=0.001, respectively). Vascular dilatation and congestion were significantly more prominent in all groups compared to the control group (P=0.001 for all).Conclusion: Our results confirm that fullerenol C60 has protective effects against skeletal muscle damage resulting from I/R in diabetic rats. Future studies conducted to evaluate these effects may help illuminate the action mechanism of fullerenol C60 and pathophysiology underlying the tissue damage related to I/R injury.

MicroRNA-19 restores vascular endothelial cell function in lower limb ischemia-reperfusion injury through the KLF10-dependent TGF-β1/Smad signaling pathway in rats.

Ischemia-reperfusion injury (IRI) is a severe problempatients diagnosed with acute limb ischemia. Recently, microRNAs (miR) have emerged as regulators of IRI as well as ischemic preconditioning and ischemic postconditioning. Therefore, usingrat models, this study aims to explore all of the possible mechanisms that miR-19 exhibits with its relation to the transforming growth factor beta (TGF-β1)/Smad signaling pathway in the lower limb IRI. An immunofluorescence staining method was used to identify the Krueppel-like factor 10 (KLF10) positive expression and the location of KLF10 expression. The targeting relationship that miR-19 has with KLF10 was verified by the dual-luciferase reporter gene assay. Vascular endothelial cells (VECs) were treated with elevated or suppressed miR-19 or KLF10 knockdown. A 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay was used to test cell proliferation, and flow cytometry was employedto detect bothcell cycle and apoptosis. The KLF10-positive expression in the VECs (both in cytoplasm and nucleus) was found tobe elevated in the IRI rats. We found that miR-19 was downregulated, KLF10 upregulated, and the TGF-β1/Smad signaling pathway activated in the vascular epithelial tissues of IRI rats. KLF10 is a target gene of miR-19. Overexpression of miR-19 decreased the expression of KLF10, TGF-β1, and Smad2/3. Decreased miR-19 inhibited VEC proliferation, arrested VECs at the G1 phase, and promoted the apoptosis of VECs following their lower limb I/R injury. These results indicate miR-19 as being an inhibitor in the VEC injury of IRI via the TGF-β1/Smad signaling pathway by suppression of KLF10.

Effects of dexmedetomidine and thymoquinone on erythrocyte deformability in lower limb ischemia reperfusion injury in streptozotocin-induced diabetic rats.

In this study we aimed to evaluate the effect of dexmedetomidine and thymoquinone on erythrocyte deformability in lower limb ischaemia-reperfusion (IR) injury in streptozotocin-induced diabetic rats. Thirty Wistar albino rats were equally divided into 5 groups (n = 6); randomized control group (Group C), diabetes control group (Group DC), DIR group (Group DIR), DIR group with thymoquinone 25 mg.kg‒1 intraperitoneally (Group DIRT) and Group DIR with dexmedetomidine 100 µg.kg‒1 intraperitoneally (Group DIRD). Erythrocyte packs were prepared from heparinized blood samples and deformability measurements were performed. IR significantly increased the relative resistance, a marker of erythrocyte deformability when compared to control group (p < 0.05).There were significant differences among the groups in comparisons with ANOVA test (p < 0.0001). Comparisons of the groups DIRD and DIRT revealed similar results (p = 0.824). The values of Group DIR were significantly higher than those of the control, DC, DIRD and DIRT groups (p < 0.0001, p = 0.001, p = 0.004, p = 0.002, respectively).The values of the DC, DIR, DIRD and DIRT groups were significantly higher than those of the control group (p < 0.0001, all). Erythrocyte deformability may cause more problems in microcirculation. Dexmedetomidine and thymoquinone may be useful in reducing the adverse effects of this type of injury (Fig. 1, Ref. 41).

Effect of Different Doses of Pregabalin on Erythrocyte Deformability in Rats with Lower Limb Ischemia Reperfusion Injury

Effect of Different Doses of Pregabalin on Erythrocyte Deformability in Rats with Lower Limb Ischemia Reperfusion Injury

Effects of dexmedetomidine on renal tissue after lower limb ischemia reperfusion injury in streptozotocin induced diabetic rats

ABSTRACTAim: The aim of this study was to investigate whether dexmedetomidine – administered before ischemia – has protective effects against lower extremity ischemia reperfusion injury that induced by clamping and subsequent declamping of infra-renal abdominal aorta in streptozotocin-induced diabetic rats.Material and Methods: After obtaining ethical committee approval, four study groups each containing six rats were created (Control (Group C), diabetes-control (Group DM-C), diabetes I/R (Group DM-I/R), and diabetes-I/R-dexmedetomidine (Group DM-I/R-D). In diabetes groups, single-dose (55 mg/kg) streptozotocin was administered intraperitoneally. Rats with a blood glucose level above 250 mg/dl at the 72nd hour were accepted as diabetic. At the end of four weeks, laparotomy was performed in all rats. Nothing else was done in Group C and DM-C. In Group DM-I/R, ischemia reperfusion was produced via two-hour periods of clamping and subsequent declamping of infra-renal abdominal aorta. In Group DM-I/R-D, 100 μg/kg dexmedetomidine was administered intraperitoneally 30 minutes before ischemia period. At the end of reperfusion, period biochemical and histopathological evaluation of renal tissue specimen were performed.Results: Thiobarbituric acid reactive substance (TBARS), Superoxide dismutase (SOD), Nitric oxide synthase (NOS), Catalase (CAT) and Glutathion S transferase (GST) levels were found significantly higher in Group DM-I/R when compared with Group C and Group DM-C. In the dexmedetomidine-treated group, TBARS, NOS, CAT, and GST levels were significantly lower than those measured in the Group D-I/R. In histopathological evaluation, glomerular vacuolization (GV), tubular dilatation (TD), vascular vacuolization and hypertrophy (VVH), tubular cell degeneration and necrosis (TCDN), tubular hyaline cylinder (THC), leucocyte infiltration (LI), and tubular cell spillage (TCS) in Group DM-I/R were significantly increased when compared with the control group. Also, GV, VVH, and THC levels in the dexmedetomidine-treated group (Group DM-I/R-D) were found significantly decreased when compared with the Group DM-I/R.Conclusion: We found that dexmedetomidine − 100 μg/kg intraperitoneally – administered 30 minutes before ischemia in diabetic rats ameliorates lipid peroxidation, oxidative stress, and I-R-related renal injury. We suggest that dexmedetomidine administration in diabetic rats before I/R has renoprotective effects.

Levosimendan Administration in Limb Ischemia: Multicomponent Signaling Serving Kidney Protection.

Aims and ObjectivesAcute renal failure is a severe complication of lower extremity major arterial reconstructions, which could even be fatal. Levosimendan is a dual-acting positive inotropic and vasodilatory agent, which is suspected to have protective effects against cardiac ischemia. However, there is no data available on lower limb or remote organ ischemic injuries therefore the aim of the study was to investigate the effect of levosimendan on lower limb ischemia-reperfusion injury and the corollary renal dysfunction.MethodsMale Wistar rats underwent 180 min bilateral lower limb ischemia followed by 4 or 24 hours of reperfusion. Intravenous Levosimendan was administered continuously (0.2μg/bwkg/min) throughout the whole course of ischemia and the first 3h of reperfusion. Results were compared with sham-operated and ischemia-reperfusion groups. Hemodynamic monitoring was performed by invasive arterial blood pressure measurement. Kidney and lower limb muscle microcirculation was registered by a laser Doppler flowmeter. After 4h and 24h of reperfusion, serum, urine and histological samples were collected.ResultsSystemic hemodynamic parameters and microcirculation of kidney and the lower limb significantly improved in the Levosimendan treated group. Muscle viability was significantly preserved 4 and 24 hours after reperfusion. At the same time, renal functional laboratory tests and kidney histology demonstrated significantly less expressive kidney injury in Levosimendan groups. TNF-α levels were significantly less elevated in the Levosimendan group 4 hours after reperfusion.ConclusionThe results claim a protective role for Levosimendan administration during major vascular surgeries to prevent renal complications.

Anti-endotoxin Hyperimmune Globulin Attenuates Portal Cytokinaemia, Phagocytic Cell Priming, and Acute Lung Injury after Lower Limb Ischaemia-reperfusion Injury

Anti-endotoxin Hyperimmune Globulin Attenuates Portal Cytokinaemia, Phagocytic Cell Priming, and Acute Lung Injury after Lower Limb Ischaemia-reperfusion Injury

Anti-endotoxin Hyperimmune Globulin Attenuates Portal Cytokinaemia, Phagocytic Cell Priming, and Acute Lung Injury after Lower Limb Ischaemia-reperfusion Injury

Acute limb ischaemia is a common and often lethal clinical event. Reperfusion of an ischaemic limb has been shown to induce a remote gut injury associated with transmigration of endotoxin into the portal and systemic circulation, which in turn has been implicated in the conversion of the sterile inflammatory response to a sepsis syndrome, after lower torso ischaemia-reperfusion injury. This study tests the hypothesis that an anti-endotoxin hyperimmune globulin attenuates ischaemia-reperfusion (I/R) associated sepsis syndrome. Prospective, randomised placebo controlled trial, animal experiment. Experimental porcine model, bilateral hind limb I/R injury, randomised to receive anti-endotoxin hyperimmune globulin or placebo. Bilateral hind limb I/R injury significantly increased intestinal mucosal acidosis, portal endotoxaemia, plasma cytokine (TNF-alpha, IL-6, IL-8) concentrations, circulating phagocytic cell priming and pulmonary leukosequestration, oedema, and capillary-alveolar protein leak. Conversely, pigs treated with anti-endotoxin hyperimmune globulin (IgG) 20mg/kg at onset of reperfusion had significantly reduced portal endotoxaemia, early circulating phagocytic cell priming, plasma cytokinaemia and attenuation of acute lung injury. Endotoxin translocation across a hyperpermeable gut barrier, phagocytic cell priming and cytokinaemia are key events of limb I/R injury induced systemic inflammation and acute lung injury. This study shows that an anti-endotoxin hyperimmune globulin attenuates portal endotoxaemia, which may reduce early phagocytic cell activation, cytokinaemia and ultimately acute lung injury.

Lower limb ischaemia-reperfusion injury causes endotoxaemia and endogenous antiendotoxin antibody consumption but not bacterial translocation.

It has been suggested that reperfusion of the acutely ischaemic lower limb alters gut permeability. The effect of lower limb ischaemia-reperfusion on systemic endotoxin and antiendotoxin antibody concentrations and the incidence of bacterial translocation was investigated. Systemic endotoxin and antiendotoxin antibody concentrations were measured in five groups of male Wistar rats: control, after 3 h of bilateral hind limb ischaemia alone, and after 3 h of bilateral hind limb ischaemia followed by 1, 2 or 3 h of reperfusion. A second experiment examined translocation of indigenous bacteria following 2 h of reperfusion in a similar model. Ischaemia followed by reperfusion for 1, 2 or 3 h caused a significant increase in plasma endotoxin concentration to mean(s.e.m.) 10.0(3.0), 44.8(19.2) and 20.2(6.2) pg/ml compared with that in control animals (2.58(0.91) pg/ml) or animals in the ischaemia alone group (1.2(0.9) pg/ml) (P < 0.05). This was associated with a significant reduction in endogenous antiendotoxin antibody (immunoglobulin (Ig) G and IgM) concentration. No significant bacterial translocation was detected in any of the groups studied. These results demonstrate that a remote and isolated ischaemia-reperfusion injury to the lower limb, in the absence of infection or bacterial translocation, causes endotoxaemia. Further studies are needed to evaluate the role of endogenous antiendotoxin antibodies in this situation.

Gut Mucosal Injury Is Attenuated by Recombinant Bactericidal/Permeability-Increasing Protein in Hind Limb Ischemia-Reperfusion Injury

Lower limb ischemia-reperfusion injury (IRI) is associated with increased gut permeability to endotoxin, which not only directly damages enterocytes but also stimulates a systemic inflammatory response syndrome (SIRS), compounding gut injury. Recombinant bactericidal/permeability-increasing protein (rBPI21) is a novel anti-endotoxin therapy with proven benefit in sepsis. Its potential role in modulating remote gut injury in hind limb IRI was studied. Male Wistar rats were chosen for a prospective randomized control trial (n = 10 per group). The control group and two groups undergoing 3 hr bilateral hind limb ischemia with 2 hr reperfusion (I/R) were randomized to receive intravenously either control protein thaumatin at 2 mg/kg or rBPI21 at 2 mg/kg, respectively. Quantitative morphometric assessment of the small bowel was used as a measure of gut injury and, using an ex vivo everted gut sac model, translocation of 14C-labeled polyethylene glycol (PEG) was used as a measure of gut permeability. Our results indicate that hind limb IRI is associated with remote gut mucosal injury and increased permeability to macromolecules. rBPI21 anti-endotoxin therapy modulates remote gut injury associated with lower limb IRI in this model.

Recombinant bactericidal/permeability–increasing protein attenuates the systemic inflammatory response syndrome in lower limb ischemia-reperfusion injury

Objectives: Hind limb ischemia-reperfusion (I/R) injury increases gut permeability, and resultant endotoxemia is associated with an amplified systemic inflammatory response syndrome leading to multiple organ dysfunction syndrome. We studied the potential role of recombinant bactericidal/permeability–increasing protein (rBPI21 ), a novel antiendotoxin therapy, in modulating endotoxin-enhanced systemic inflammatory response syndrome in hind limb I/R injury. Methods: In this prospective, randomized, controlled, experimental animal study, 48 male Wistar rats, weighing 300 to 350 g, were randomized to a control group (sham) and five groups undergoing 3 hours bilateral hind limb ischemia with 2 hours reperfusion (I/R) (n = 8 per group). The control and untreated I/R groups received thaumatin, a control- protein preparation, at 2 mg/kg. Treatment groups were administered rBPI21 intravenously at 1, 2, or 4 mg/kg body weight at the beginning of reperfusion; an additional group was administered rBPI21 intravenously at 2 mg/kg after 1 hour of reperfusion. Plasma interleukin-6 concentration was estimated by bioassay as a measure of systemic inflammation. Plasma endotoxin concentration was determined by use of an amebocyte lysate chromogenic assay. Crossreactive immunoglobulin G and M antibodies to the highly conserved inner core region of endotoxin were measured by use of an enzyme-linked immunosorbent assay. The lung tissue wet-to-dry weight ratio and myeloperoxidase concentration were used as markers of edema and neutrophil sequestration, respectively. Results: I/R provoked highly significant elevation in plasma interleukin-6 concentrations (1351.20 pg/mL [860.16 - 1886.40 pg/mL]) compared with controls (125.32 pg/mL [87.76-157.52 pg/mL; P <.0001]), but treatment with rBPI21 2 mg/kg at onset of reperfusion (715.89 pg/mL [573.36-847.76 pg/mL]) significantly decreased interleukin-6 response compared with the nontreatment group ( P <.016). I/R increased plasma endotoxin concentrations significantly (21.52 pg/mL [6.20-48.23 pg/mL]), compared with control animals (0.90 pg/mL [0.00-2.30 pg/mL; P <.0001]), and treatment with rBPI21 4 mg/kg at reperfusion significantly decreased endotoxemia (1.30 pg/mL [1.20-2.20 pg/mL]), compared with the untreated group ( P <.001). The lung tissue myeloperoxidase level was significantly increased in the untreated I/R group (208.18% [128.79%-221.81%]), compared with in controls (62.00% [40.45%-80.92%; P <.0001]), and attenuated in those treated with rBPI21 2 mg/kg (129.54% [90.49%-145.78%; P <.05]). Data represent median and interquartile range, comparisons made with the nonparametric Mann-Whitney U test. Conclusions: These findings show that hind limb ischemia-reperfusion injury is associated with endotoxemia, elevations in plasma interleukin-6, and pulmonary leukosequestration. Treatment with rBPI21 after ischemia reduces endotoxemia, the interleukin-6 response, and attenuates pulmonary leukosequestration in response to hind limb reperfusion injury. (J Vasc Surg 2001;33:840-6.)

Recombinant bactericidal/permeability-increasing protein attenuates remote gut mucosal injury in lower limb ischaemia-reperfusion injury

Recombinant bactericidal/permeability-increasing protein attenuates remote gut mucosal injury in lower limb ischaemia-reperfusion injury

Pharmacological manipulation of gastrocnemius muscle blood flow in an animal model of reperfusion injury

Despite technically satisfactory surgery for acute lower limb ischaemia reperfusion injury may result in failure of limb salvage and the need for amputation. An animal model using the rat hind limb has been developed which demonstrates this complication. A tourniquet was applied to one hind limb for 6 h and then released. Gastrocnemius muscle blood flow in both hind limbs was assessed using radiolabelled microspheres and a perfusion index calculated between the revascularized and normal hind limbs and the results compared with similar measurements in control animals and rats with a tourniquet still in situ (ischaemic). Following 10 min the median perfusion index in reperfused animals was significantly less than that in control animals (0.12 ± 2 inter-quartile range 0.02–0.43) versus 1.05 (0.68–1.18), P < 0.01) but similar to the results in rats with a tourniquet still in situ [0.04 (0.00–0.07), ns], thus demonstrating low reflow following tourniquet release. After 120 min revascularization a phase of relative reperfusion occurred with perfusion indices becoming higher than those in animals with a tourniquet in situ (0.48 (0.11–0.70) versus 0.02 (0.01–0.07), P < 0.05) but remaining lower than those in control rats [0.97 (0.79–1.13), P < 0.05]. Finally after 240 min, reperfusion injury occurred with perfusion being similar to that in animals with a tourniquet applied [0.05 [0.01–0.38) versus 0.03 (0.00–0.07), ns] and less than that in the normal rats [1.01 (0.73–1.16), P < 0.01]. Attempts to modify these reductions in muscle perfusion pharmacologically have demonstrated that a superoxide radical scavenger (superoxide dismutase and catalase) abolished low reflow (0.94 (0.54–1.12) versus 0.12 (0.02–0.43), P < 0.01). In contrast dimethylthiourea, an hydroxyl radical scavenger, prevented the phase of relative reperfusion (0.04 (0.02–0.21) versus 0.48 (0.11–0.70), P < 0.01. Sodium nitroprusside, a vasodilator, increased perfusion at 240 min [0.41 (0.11–1.22] versus 0.05 (0.01–0.38], P < 0.05] with 6 out of 15 rats having a normal perfusion index at the time when reperfusion injury would be expected to occur.