Ischemia-reperfusion injury pathophysiology, part I

Inflammatory biomarker concentrations in dogs with gastric dilatation volvulus with and without 24-h intravenous lidocaine

Background

Canine gastric dilatation volvulus (GDV) is characterized by tissue ischemia, reperfusion, and systemic inflammation. Evidence exists that lidocaine exerts anti-inflammatory properties and potentially improves outcome.

Design and setting

Prospective, randomized observational cohort study in client-owned dogs with GDV.

Objective

The primary objective of the study was the determination of pro- and anti-inflammatory biomarker concentrations in dogs with GDV with and without intravenous (IV) lidocaine therapy. The second objective was the evaluation of side effects of lidocaine.

Methods

Of 35 dogs included in the study, 20 dogs were assigned to receive lidocaine (LIDO) (2 mg/kg initially, followed by a continuous infusion at a rate of 50 μg/kg/min over 24 h) and 15 dogs not to receive lidocaine (NO-LIDO). Plasma concentrations of cytokines interleukin (IL)-6, IL-7, IL-8, IL-10, IL-15, IL-18, interferon gamma, keratinocyte chemotactic-like, monocyte chemotactic protein, and C-reactive protein (CRP) were measured at admission (prior any therapeutic intervention, T0), immediately after surgery (T1), at 24 h (T24), and at 48 h (T48) post-surgery.

Results

No significant differences in concentrations of any cytokines were found between the LIDO- and the NO-LIDO group. Significant lower CRP concentrations (median [range]) were found in dogs with lidocaine compared to dogs without at T24 (97.5 pg/mL [46.3-161.7] vs. 127.9 pg/mL [26.9-182.0]; p = 0.046) and T48 (73.7 pg/mL [18.4-169.4] vs. 116.3 pg/mL [71.4-176.8]; p = 0.002). Dogs receiving lidocaine exhibited significantly impaired mentation, a prolonged period of anorexia, and longer hospitalization compared to dogs without lidocaine.

Conclusion

Lidocaine administration had no impact on the plasma levels of cytokines during the 48-h study period, but significantly lower CRP concentrations were found at T24 and T48. Lidocaine's potential side effects require careful decision making regarding its use.

Protective effects of empagliflozin on testicular injury induced by torsion/detorsion in adult male rats

INTRODUCTION

Testicular torsion is a known urologic emergency condition and one of the common causes of infertility in males. Hence, prompt diagnosis and treatment play a crucial role in prevention of testicular injury. It has been observed that empagliflozin, a drug for management of hyperglycemia, has anti-oxidative properties against different pathologies, the most important of which are ischemia reperfusion related injuries.

OBJECTIVE

This study aims to evaluate the protective effects of empagliflozin on a testicular torsion injury in adolescent rats followed by ischemia/reperfusion (I/R) phenomena.

STUDY DESIGN

Thirty-six rats were randomly assigned into three groups including sham-operated group received all surgical procedures except testicular torsion-detorsion, torsion/detorsion + dimethyl sulfoxide (DMSO) as vehicle, and torsion/detorsion + empagliflozin (10 mg/kg). Testicular torsion was performed for 2 h through rotating right testis 720° in the clockwise direction. Thirty minutes before detorsion, a single intraperitoneal dose of empagliflozin was injected to treatment group. Four hours later, orchiectomy was conducted for histopathological and biochemical examinations of testicular tissue specimens.

RESULTS

The malondialdehyde (MDA) content in the torsion/detorsion animals was markedly greater than in the animals under sham operated procedure. Moreover, the testicular MDA levels in the torsion/detorsion + empagliflozin group were significantly lower than in the torsion/detorsion group. Also, significant decreases observed in catalase, superoxide dismutase, and glutathione peroxidase activities in the torsion/detorsion group in comparison with sham operated group. These values were significantly improved in the empagliflozin group. Furthermore, histopathological examinations also revealed severe testicular injury which were improved by empagliflozin administration.

DISCUSSION

Empagliflozin prevented increases in oxidative stress markers and subsequently reduced the tissue injury induced by torsion/detorsion in the current study.

CONCLUSION

It can be concluded that administration of empagliflozin before prevents I/R related cellular damage in testicular torsion, possibly via oxidative stress inhibition.

A model to visualize the fate of iron after intracranial hemorrhage using isotopic tracers and elemental bioimaging

Hemoglobin-iron is a red-blood-cell toxin contributing to secondary brain injury after intracranial bleeding. We present a model to visualize an intracerebral hematoma and secondary hemoglobin-iron distribution by detecting 58Fe-labeled hemoglobin (Hb) with laser ablation-inductively coupled plasma-mass spectrometry on mouse brain cryosections after stereotactic whole blood injection for different time periods. The generation of 58Fe-enriched blood and decisive steps in the acute hemorrhage formation and evolution was evaluated. The model allows to visualize and quantify 58Fe with high spatial resolution and striking signal-to-noise ratio. Script-based evaluation of the delocalization-depth revealed ongoing 58Fe delocalization in the brain even six days after hematoma induction. Collectively, the model can quantify the distribution of Hb-derived iron post-bleeding, providing a methodological framework to study the pathophysiological basis of cell-free Hb toxicity in hemorrhagic stroke.

The protective effects of trimetazidine against ovary ischemia-reperfusion injury via the TLR4/Nf-kB signal pathway

Late diagnosis and treatment of ovarian ischemia can lead to worsening of ischemia, irreversible damage to ovarian functions and infertility. In this process, there is no approved medical treatment that can reduce the negative effects of ischemia and contribute positively to ovarian functions during reperfusion after detorsion. Rats were randomly assigned into one of six groups of eight animals each. The groups were designed as follows: The control group, The ischemia(I) group, The Ischemia + Trimetazidine (I + TMZ) (20 mg/kg) group, and The ischemia-reperfusion group (I/R). The Ischemia-Reperfusion + Trimetazidine (I/R + TMZ) (20 mg/kg) group, and The Sham + Trimetazidine (Sham + TMZ) (20 mg/kg) group. In this study performed thiobarbituric acid reactive substances (TBARS), total thiol (-SH), interleukin 1 beta (IL-1β), interleukin 6 (IL-6), toll-like receptor 4 (TLR4), and nuclear factor-kappa B(NF-κβ). Increased oxidative stress and inflammation were as a result of ovarian I and I/R application. Trimetazidine (TMZ), was sufficient to reduce the oxidative stress and inflammation. TLR4 and NF-κβ, which were upregulated by oxidative stress and inflammation, were regressed by TMZ. TMZ should be considered as a potential therapeutic agent in addition to surgery in the clinical treatment of ovarian torsion.

Protective Effects of Hydrogen-Rich Saline on Experimental Intestinal Volvulus in Rats

BACKGROUND

Intestinal volvulus can cause morbidity and mortality. Surgical reduction, on the other hand, could result in ischemia-reperfusion (I/R) injury. Hydrogen rich saline solution (HRSS neutralizes free radicals in the body. This study aimed to investigate the effects of HRSS in I/R injury in experimental intestinal volvulus in rats.

METHODS

Thirty rats were randomly allocated into 5 groups. All procedures were done under general anesthesia and sterile conditions in each animal. Five ml/kg of saline and HRSS were administered intraperitoneally (ip) in Sham (Group 1) and HRSS (Group 2) groups, respectively. Groups 3, 4, and 5 constituted the study groups in which volvulus was created in a 5-cm- long ileal segment 2 cm proximal to the ileocecal valve. After 2 hours the volvuli were reduced and following 2 hours of reperfusion, these segments were removed. In volvulus-I/R group (Group 3) no additional procedure was done. HRSS was administered shortly before reperfusion (reduction of the volvulus) in Treatment I (Group 4) and 1 h before experimental volvulus in Treatment II (Group 5) groups. Blood and intestinal tissue samples were obtained from all rats at the 4th hour. Both tissue and blood total oxidant (TOS) and antioxidant status (TAS) levels were determined and tissue histomorphologies were studied. Oxidative stress indices (TOS ÷ TAS) (OSI) were calculated.

RESULTS

Tissue TOS and OSI levels and histomorphological injury scores were statistically lower in treatment groups than I/R group, whereas blood TOS and OSI levels were similar between the groups.

CONCLUSIONS

This study provides biochemical and histomorphological evidence that HRSS prevents intestinal damage in I/R injury caused by volvulus.

The effects of dexketoprofen on renal ischemia-reperfusion injury: an experimental study

Objective

Ischemia/reperfusion (I/R) may cause irreversible damage to tissues and organs. We evaluated the effects of dexketoprofen on a renal I/R model in rats.

Methods

The study included 30 male rats. Control group received 1 mL of saline. Dexketoprofen group received 1 mL (25 mg) of dexketoprofen intraperitoneally. After 60 minutes renal ischemia, 23 hours reperfusion was applied. In Sham group, laparotomy was performed with a medial line incision without any additional procedure. Changes in the plasma malondialdehyde (MDA), renal tissue MDA, plasma glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), BUN, creatinine and albumin levels, and histopathological changes were evaluated.

Results

CAT values were significantly lower in Control as compared with the Sham group. Plasma levels of MDA in the Control group were significantly higher than in the Dexketoprofen group. BUN and creatinine values were significantly higher in the Dexketoprofen group. The severity of tissue injury in the Dexketoprofen group was significantly higher than in Control and Sham groups

Conclusion

Although dexketoprofen reduces the I/R-induced systemic inflammation, it increases renal tissue damage.

Kinetics of Plasma Cytokines, Angiopoietin-2, and C-Reactive Protein in Dogs With Gastric Dilatation Volvulus

Background: The degree of systemic inflammation, reperfusion injury and endothelial activation are potentially important determinants of clinical outcomes in dogs with gastric dilatation volvulus (GDV).

Objective: To evaluate plasma concentrations and kinetics of inflammatory markers in dogs with GDV over a time frame of 48 h, and to compare to healthy dogs.

Design and Setting: Prospective, observational cohort study in client-owned dogs with GDV.

Materials and Methods: Fifteen dogs with GDV and 9 healthy control dogs were enrolled. Plasma concentrations of interleukin (IL)-6, IL-7, IL-8, IL-10, IL-15, IL-18, interferon gamma (IFN-γ), keratinocyte chemotactic-like, monocyte chemotactic protein (MCP)-1, Angiopoietin (Ang)-2, and C-reactive protein (CRP) were measured at admission (prior any therapeutic intervention, (T0), immediately after surgery (T1), 24 ± 4 h (T24), and 48 ± 4 h (T48) post-surgery. Cytokines were measured using multiplex magnetic bead assay. Plasma Ang-2 was measured with a commercial human ELISA test kit validated for dogs.

Results: Dogs with GDV had significantly higher plasma concentrations of IFN-γ and IL-10 compared to healthy control dogs at all time points. Concentrations of IL-6 were significantly higher at T1 and T24, concentrations of MCP-1 at T24, and concentrations of CRP at T24 and T48. A significant increase between T0 and T1 was found for IL-6, IL-10, and CRP, between T1 and T24 for IL-8, IFN-γ, MCP-1, and CRP, and between T24 and T48 for IL-15, Ang-2, and CRP. A significant decrease between T0 and T1 was found for IL-7, IL-8, IL-15, IL-18, and Ang-2; between T1 and T24 for IL-6 and KC-like; and between T24 and T48 for IL-6.

Conclusion: In GDV dogs, a mild pro-inflammatory reaction was present at admission, which peaked immediately after and up to 24 h post-surgery, mainly represented by IL-6, IFN-γ, MCP-1, and CRP, and which decreased at T48. In addition, the anti-inflammatory IL-10 was increased in GDV dogs at all time points.

Vitamin C in Health and Disease: A Companion Animal Focus

Vitamin C is synthesized in the liver in most species, including dogs and cats, and is widely distributed through body tissues. Vitamin C has an important physiologic role in numerous metabolic functions including tissue growth and maintenance, amelioration of oxidative stress, and immune regulation. It is also a co-factor in the production of important substances such as catecholamines and vasopressin. Decreased vitamin C levels have been documented in a wide variety of diseases, and in critically ill human patients may be associated with increased severity of disease and decreased survival. Intravenous supplementation with vitamin C has been proposed as a potential life-saving treatment in conditions such as septic shock, and results of small some human trials are promising. Data in companion in animals is very limited, but the possible benefits and , seemingly low risk of adverse effects , and the low cost of this treatment make vitamin C therapy a promising area of future investigation in critically ill dogs and cats.

Acid-Base, Electrolyte and Lactate Abnormalities as Well as Gastric Necrosis and Survival in Dogs With Gastric Dilation-Volvulus Syndrome. A Retrospective Study in 75 Dogs

Gastric dilation-volvulus (GDV) syndrome in dogs is associated with complex metabolic, acid-base, and electrolyte abnormalities. The aim of this study was to evaluate previously analyzed factors (lactate and BE) in combination with other acid-base parameters (pH, pCO₂, bicarbonate, base excess [BE], anion gap [AG], and strong ion difference) and electrolyte concentrations and to evaluate their association with the incidence of gastric necrosis and outcome in dogs with GDV. A retrospective study in 75 dogs with gastric dilation-volvulus syndrome, University veterinary teaching hospital. Medical records were reviewed including signalment, history, initial plasma lactate, acid-base parameters, and electrolyte concentrations, surgical findings and outcome. The overall mortality was 18.7%. In dogs with gastric necrosis, higher initial plasma lactate (median 5.84 vs. 3.36 mmol/L) and AG (20.7 vs. 16.55 mmol/L) and lower pH (7.29 vs. 7.36), bicarbonate (18.7 vs. 22.9 mmol/L), and BE concentration (-8.1 vs. -1.85 mmol/L) were found compared to dogs without gastric necrosis. Anorganic phosphorus was the only electrolyte investigated for which a significant difference was noted between dogs with and without gastric necrosis (1.93 vs. 1.39 mmol/L). The initial plasma lactate concentration (3.36 mmol/L vs. 9.68 mmol/L) and AG (16.8 vs. 20.95 mmol/L) were lower in survivors than nonsurvivors. Survivors had higher pH (7.35 vs. 7.27), bicarbonate concentrations (22.9 vs. 17.35 mmol/L), and BE (-1.9 vs. -9.55 mmol/L) compared to nonsurvivors. Anorganic phosphorus was ultimately the only electrolyte with a significant difference between survivors and nonsurvivors (1.4 vs. 1.84 mmol/L). A multivariate logistic regression model of combination lactate, pH, bicarbonate, BE, AG, and anorganic phosphorus identified pH ≤7.331 and bicarbonate as factors independently associated with gastric necrosis. Similarly, pH ˃7.331, bicarbonate and anorganic phosphorus were independently associated with outcome. Higher initial plasma lactate, AG and anorganic phosphorus levels, and lower pH, BE and bicarbonate concentrations were found in GDV dogs with gastric necrosis. Similarly, initially higher plasma lactate, AG and anorganic phosphorus concentrations, and lower pH, BE and bicarbonate were found in GDV dogs who required euthanasia or who died after surgery. Of these parameters, pH and bicarbonate were strongly and independently associated with gastric necrosis, and pH, bicarbonate and phosphorus were independently associated with outcome.

Establishment of a model for equine small intestinal disease: effects of extracorporeal blood perfusion of equine ileum on metabolic variables and histological morphology - an experimental ex vivo study

BACKGROUND

In horses a number of small intestinal diseases is potentially life threatening. Among them are Equine Grass Sickness (EGS), which is characterised by enteric neurodegeneration of unknown aetiology, as well as reperfusion injury of ischaemic intestine (I/R), and post-operative ileus (POI), common after colic surgery. The perfusion of isolated organs is successfully used to minimize animal testing for the study of pathophysiology in other scenarios. However, extracorporeal perfusion of equine ileum sourced from horses slaughtered for meat production has not yet been described. Therefore the present study evaluated the potential of such a model for the investigation of small intestinal diseases in an ex vivo and cost-efficient system avoiding experiments in live animals.

RESULT

Nine ileum specimens were sourced from horses aged 1-10 years after routine slaughter at a commercial abattoir. Ileum perfusion with oxygenated autologous blood and plasma was successfully performed for 4 h in a warm isotonic bath (37.0-37.5 °C). Ileum specimens had good motility and overall pink to red mucosa throughout the experiment; blood parameters indicated good tissue vitality: 82 ± 34 mmHg mean arterial partial pressure of oxygen (pO₂) compared to 50 ± 17 mmHg mean venous pO_2, 48 ± 10 mmHg mean arterial partial pressure of carbon dioxide (pCO₂) compared to 66 ± 7 mmHg venous pCO₂ and 9.8 ± 2.8 mmol/L mean arterial lactate compared to 11.6 ± 2.7 mmol/L venous lactate. There was a mild increase in ileum mass reaching 105 ± 7.5% of the pre-perfusion mass after 4 hours. Histology of haematoxylin and eosin stained biopsy samples taken at the end of perfusion showed on average 99% (±1%) histologically normal neurons in the submucosal plexus and 76.1% (±23.9%) histologically normal neurons in the myenteric plexus and were not significantly different to control biopsies.

CONCLUSION

Extracorporeal, normothermic perfusion of equine ileum over 4 h using autologous oxygenated blood/plasma perfusate showed potential as experimental model to test whether haematogenous or intestinal exposure to neurotoxins suspected in the pathogenesis of EGS can induce neuronal damage typical for EGS. Also, this model may allow investigations into the effect of pharmaceuticals on I/R injury, as well as into the pathogenesis of equine POI.

The effect of rutin on ovarian ischemia-reperfusion injury in a rat model

The effect of rutin on ovarian ischemia-reperfusion (I/R) injury was investigated in this experimental study. Eighteen Wistar albino female rats were divided into three groups as follows: I/R group (IRG; n = 6), 50 mg/kg rutin + I/R group (RG; n = 6), and a healthy control group scheduled for a sham operation (SG; n = 6). 2 h of ischemia and following 2 h of reperfusion were created in the IRG and RG by using a torsion model involving atraumatic vascular clips. Rutin, a flavonoid glycoside, was injected intraperitoneally at the dose of 50 mg/kg to RG group 1 h before reperfusion. Then, rats were euthanized and their ovaries were removed for biochemical and histopathological examination and also assessment of the gene expressions. IRG group had a significant increase in malondialdehyde (MDA) levels, in the expressions of tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β), and also in the activity of cyclooxygenase 2 (COX-2) unlike the significant decrease in total glutathione (tGSH) levels and the activity of COX-1 when compared to the SG group. However, rutin significantly decreased MDA levels, the expressions of TNF-α and IL-1β, and also the activity of COX-2 while it increased significantly tGSH levels and the activity of COX-1 in the RG group in comparison with the IRG group. Rutin ameliorated the I/R-induced ovarian injury in rats via its possible antioxidative and anti-inflammatory effects.

Xijiao Dihuang Decoction Alleviates Ischemic Brain Injury in MCAO Rats by Regulating Inflammation, Neurogenesis, and Angiogenesis

Ischemic stroke is an increasingly important public health problem, and no effective treatments are approved. Xijiao Dihuang Decoction (XDD), a famous herbal formula for treating hemorrhagic fever syndromes, has been shown to exert powerful neuroprotective property. The aim of this study was to identify the chemical constituents in XDD, observe the neuroprotective effect of XDD against acute ischemic stroke, and explore the specific mechanisms by which these effects were mediated. With UHPLC-Q/TOF-MS, 47 components in XDD were detected and 25 of them were identified. In rats subjected to MCAO, XDD ameliorated neurological deficit, histopathology changes, and infarction volume. In addition, levels of TNF-ɑ, IL-6, and IL-1β in XDD-treated group were significantly lower compared to the model group. Mechanistic studies showed that XDD inhibited MCAO-induced NF-κB activation, presenting as downregulating the expression of phospho-NF-κB p65 and preventing IκBɑ degradation. Besides, BDNF, GDNF, VEGF, bFGF, and CD34 levels were significantly increased by XDD, suggesting that the protective effects of XDD may also be associated with the promotion of neurogenesis and angiogenesis. In conclusion, these findings provided a novel regulatory pathway of the neuroprotective effect of XDD that helped rehabilitate patients with stroke.

Vascular surgery of aortic thrombosis in a dog using Fogarty maneuver - technical feasibility

Aortic thromboembolism is a rare and life‐threatening disease in dogs. This report aims to describe the successful surgical treatment by use of a Fogarty Thrombectomy Catheter in an 8‐year‐old patient. The postsurgical intensive care therapy to prevent ischemia‐reperfusion syndrome is specified, despite poor outcome in our case (owner elected euthanasia).

Cardioprotective Effects of Malvidin Against Isoproterenol-Induced Myocardial Infarction in Rats: A Mechanistic Study

Background

Malvidin (alvidin-3-glucoside) is a polyphenol that belongs to the class of natural anthocyanin, which is abundantly found in red wines, colored fruits, and the skin of red grapes. Therefore, the current investigation was intended to evaluate the effect of malvidin against myocardial infarction induced by isoproterenol in the rats.

Material/Methods

The cardioprotective effects was assessed by determining the effect of malvidin on the activities of endogenous antioxidants – catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH) – and on the levels of lipid peroxidation and serum marker enzymes. The serum levels of IL-6 and TNF-α were also determined using an enzyme-linked immunosorbent assay (ELISA) kit.

Result

The present study demonstrated a significant cardioprotective effect of malvidin by restoring the defensive activities of endogenous antioxidants – catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH) – and by reducing the levels of lipid peroxidation and serum marker enzymes lactate dehydrogenase (LD) and creatine kinase (CK). Malvidin significantly ameliorated the histopathological changes and impaired mitochondria in the cardiac necrosis stimulated with isoproterenol. Additionally, the results also demonstrated that nuclear translocation of Nrf-2 and subsequent HO-1 expression might be associated with nuclear factor kappa B (NF-κB) pathway activation.

Conclusions

Our findings suggest that malvidin exerts cardioprotective effects that might be due to possible strong antioxidant and anti-inflammatory activities. Therefore, this study provides the basis for the development of malvidin as a safe and effective treatment of myocardial infarction.

Improvement of memory and learning by intracerebroventricular microinjection of T3 in rat model of ischemic brain stroke mediated by upregulation of BDNF and GDNF in CA1 hippocampal region

Background

Ischemic stroke is a common leading cause of death and disability with lack of effective therapies. In this study, T3 was intra-ventricularly injected to evaluate gene expression and protein concentration of and brain-derived neurotrophic factor (BDNF) and Glial cell-derived neurotrophic factor (GDNF) in hippocampal CA1 region in rat model of brain ischemia/reperfusion (I/R).

Methods

In this study, transient middle cerebral artery occlusion (tMCAo) was used as model of ischemic brain stroke. Rats were randomly divided in four groups of Co, Sh, tMCAo and tMCAo + T3. Then, a single dose of intra-ventricular T3 was administered via a Hamilton syringe. Passive avoidance test was used as behavioral investigations. After 21 days, the animals were sacrificed and their brains were used for molecular and histopathological studies.

Results

T3 significantly improved the learning and memory compared with tMCAo group according to Morris water maze findings (P < 0.05). Step-through latency (STL) significantly decreased in tMCAo group (P < 0.05). There were significant increase in the STL of T3 group compared with tMCAo group (P < 0.05).A significant reduction in BDNF mRNAs and protein levels were observed in the tMCAo compared with Co and Sh group (P < 0.05). A significant increase of BDNF and GDNF mRNAs and proteins was recorded in tMCAo + T3 group compared with Co, Sh and tMCAO groups (P < 0.05).

Conclusions

The results of current study demonstrated that T3 had therapeutic effects on cerebral ischemic stroke by increasing the neurotrophic factors (BDNF, GDNF) in CA1 region of hippocampus.

Graphical abstract

The effects of intracerebroventricular microinjection of T3on memory and learning in rat model of ischemic brain stroke.

Bacterial translocation in critical illness

Bacterial translocation involves the passage of intestinal bacteria to extraintestinal sites and has been shown to increase morbidity and mortality in critical illness. This review outlines the pathophysiology of bacterial translocation, host defence mechanisms, and reviews the evidence for the clinical management of critically ill patients in order to minimise the negative outcomes associated with bacterial translocation.

Gastric mucosa injury quantification in an ischemia - Reperfusion experimental model

Gastric ischemia - reperfusion (I/R) injury is an important clinical problem, which is developed in more than 80% of critically ill patients. I/R is caused by interruption of blood supply to an organ or tissue followed by blood reflow into the exposed area, leading to multiple organ failure and death. Gastric reactance has been proposed to measure tissue injury caused by ischemia. The present study evaluates a new method to quantify gastric tissue damage due to I/R, and assess its relation to gastric reactance changes. Twenty Wistar rats were randomly assigned to 4 groups: control, ischemia, I/R 30 min, I/R 1 h. Local gastric ischemia was induced by clamping the celiac artery for 30 min and reperfusion was done for 30-60 min. In all groups, gastric impedance was measured, and then gastric mucosa samples were taken for light microscopy. There were statistical significant differences (p <;0.05) among the groups with respect to the index of gastric injury proposed, which was greater in I/R 1 h group. Also, impedance parameters increased in I/R groups with respect to control, and ischemia groups. The proposed index of gastric injury allowed gastric mucosa damage quantification, and it was related with gastric impedance increase, which is an objective method to evaluate tissue injury.

Acute Stress Decreases but Chronic Stress Increases Myocardial Sensitivity to Ischemic Injury in Rodents

Cardiovascular disease (CVD) is the largest cause of mortality worldwide, and stress is a significant contributor to the development of CVD. The relationship between acute and chronic stress and CVD is well evidenced. Acute stress can lead to arrhythmias and ischemic injury. However, recent evidence in rodent models suggests that acute stress can decrease sensitivity to myocardial ischemia-reperfusion injury (IRI). Conversely, chronic stress is arrhythmogenic and increases sensitivity to myocardial IRI. Few studies have examined the impact of validated animal models of stress-related psychological disorders on the ischemic heart. This review examines the work that has been completed using rat models to study the effects of stress on myocardial sensitivity to ischemic injury. Utilization of animal models of stress-related psychological disorders is critical in the prevention and treatment of cardiovascular disorders in patients experiencing stress-related psychiatric conditions.

Surgical Removal of a Canine Aortic Thromboembolism Secondary to Pancreatitis

A 7-year-old castrated male Pomeranian was evaluated on emergency for diagnostic work-up and treatment for acute nonpainful paraparesis. The neurologic examination suggested a L4-S3 myelopathy, but physical examination revealed lack of femoral pulses and rectal hypothermia, as well as a grade II/VI systolic heart murmur, so ischemic neuromyopathy was suspected. Clinicopathologic analysis revealed increased muscle enzymes and proteinuria. Abdominal ultrasonography confirmed aortic thromboembolism (ATE), and surgical histopathology diagnosed necrotizing pancreatitis. Surgical aortic thrombectomy was performed, and antithrombotic therapy was instituted. Pancreatitis was treated supportively. The dog was discharged to the owners after 10 days of hospitalization. Recheck examination 6 weeks after initial presentation revealed a normal neurologic examination and normal femoral pulses. The patient has had no further bouts of pancreatitis and remains neurologically normal 5 years after initial presentation. Canine ATE is relatively rare compared to the feline counterpart. Directed therapy for feline ATE is often not recommended, as underlying conditions are oftentimes ultimately fatal. Underlying etiologies for canine ATE include cardiovascular disease and endocrinopathies, but canine ATE secondary to pancreatitis has not yet been reported. Surgical removal of aortic thromboembolus should be considered as curative for pelvic limb dysfunction in the canine patient without a terminal underlying disease.

Updates in the management of the small animal patient with neurologic trauma

Neurologic trauma, encompassing traumatic brain injury (TBI) and acute spinal cord injury (SCI), is a cause of significant morbidity and mortality in veterinary patients. Acute SCIs occurring secondary to trauma are also common. Essential to the management of TBI and SCI is a thorough understanding of the pathophysiology of the primary and secondary injury that occurs following trauma. This article reviews the pathophysiology of this primary and secondary injury, as well as recommendations regarding clinical assessment, diagnostics, pharmacologic and nonpharmacologic therapy, and prognosis.

Protective effects of phosphodiesterase-4-specific inhibitor rolipram on acute ischemia-reperfusion injury in rat kidney

OBJECTIVE

To investigate the effect of Rolipram, a phosphodiesterase-4-inhibitor, on renal ischemia-reperfusion injury (IRI) in rats.

METHODS

Thirty rats were divided into 5 different groups of 6 rats. Nothing was done to the control group. In the second group, the renal pedicle was clamped for 30 minutes. In the third group, 1 mg/kg of Rolipram was given by intraperitoneal injection 30 minutes before clamping. The fourth group received the same injection when the clamp was placed, as did the fifth group 30 minutes after the clamp was opened. Clamping time was set at 30 minutes. Twenty-four hours later, nephrectomy was performed in all the groups. Half of each kidney was examined histopathologically. Levels of biochemical agents, such as malondialdehyde, superoxide dismutase, and catalase, were measured in the other half.

RESULTS

The malondialdehyde (MDA) levels significantly decreased and reached control levels in the group in which Rolipram was administered 30 minutes after reperfusion (P = .07). The catalase and superoxide dismutase activities obtained from renal homogentisates of the ischemia groups were evaluated; there were striking increases in tissue levels of these 2 enzymes in the groups in which Rolipram was administered during ischemia and 30 minutes after ischemia (P < .001). Histopathologically, there was no significant difference in inflammation between the Rolipram-administrated groups compared with group 1 (control) and group 2 (IRI). Tubular necrosis and apoptosis was significantly lower in group 5 than the other groups, except group 1 (P < .001).

CONCLUSION

We suggest that in surgical procedures that can lead to renal IRI, the administration of Rolipram can decrease oxidative renal tissue damage and the severe deterioration of renal function.

Evaluation of lidocaine treatment on frequency of cardiac arrhythmias, acute kidney injury, and hospitalization time in dogs with gastric dilatation volvulus

OBJECTIVE

To assess the efficacy of IV lidocaine in decreasing complication rate and improving the outcome in dogs with gastric dilatation volvulus (GDV).

DESIGN

Prospective non-controlled study of 83 lidocaine-treated dogs with GDV compared to 47 untreated historical controls with GDV.

SETTING

University veterinary teaching hospital.

ANIMALS

One hundred and thirty client-owned dogs with naturally occurring GDV.

INTERVENTIONS

Study group dogs were treated at presentation with lidocaine (2 mg/kg, IV bolus) followed by constant rate infusion (CRI) of 0.05 mg/kg/min for 24 h. Historical control dogs did not receive any lidocaine.

MEASUREMENTS AND MAIN RESULTS

There were no group differences in age, body weight, time lag from onset of clinical signs to presentation, rectal temperature and pulse rate at presentation, and proportion of gastric wall necrosis. The proportions of cardiac arrhythmias and acute kidney injury (AKI) were significantly (P< 0.001 and P = 0.045, respectively) lower in the lidocaine group (10/83 [12%] versus 18/47 [38.3%] and 3/83 [3.6] versus 0/47). Median hospitalization time period was shorter (P = 0.05) in the lidocaine group compared to the controls (median 48 h; range 24-360 h versus median 72 h; range 24-144 h, respectively).

CONCLUSION AND CLINICAL RELEVANCE

Early treatment with IV lidocaine bolus, followed by CRI of lidocaine for 24 h post presentation decreased the occurrence of cardiac arrhythmias, AKI and hospitalization time period significantly in lidocaine-treated dogs with GDV compared to untreated historical controls. Due to the nonblinded, placebo-uncontrolled, nonrandomized nature of the current study, further evaluation of the efficacy of lidocaine in dogs with GDV is warranted.

Effects of ischemia and reperfusion on production of nitrotyrosine, activation of eosinophils, and apoptosis in the large colonic mucosa of horses

OBJECTIVE

To assess the effects of ischemia and reperfusion on indicators of oxidative stress, activation of eosinophils, and apoptosis in the large colonic mucosa of horses.

ANIMALS

40 horses.

PROCEDURES

In 1 or two 20-cm-long segments of the pelvic flexure, ischemia was induced for 1 or 2 hours followed by no reperfusion or 30 minutes and 18 hours of reperfusion in anesthetized horses. Mucosal specimens were collected before (controls; n = 20 horses) and after each period of ischemia, and full-thickness tissue samples were collected after each period of reperfusion. Sections of colonic tissues were stained for histomorphometric analysis or assessment of eosinophil accumulation. Nitrotyrosine was identified immunohistochemically, and severity of apoptosis was determined via the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling method.

RESULTS

Numbers of mucosal eosinophils were similar before induction of ischemia, after ischemia, and after ischemia-reperfusion. Eosinophil nitrotyrosine production increased significantly during ischemia and continued through 30 minutes of reperfusion; production was decreased at 18 hours of reperfusion but remained greater than that of the controls. In other leukocytes, nitrotyrosine generation peaked at 1 hour of ischemia and again at 18 hours of reperfusion. Compared with control findings, epithelial apoptosis increased gradually at 1 through 2 hours of ischemia with no further progression after reperfusion.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that resident eosinophils in the large colon of horses react to mucosal injury from ischemia and reperfusion and may undergo oxidative stress under those conditions. Epithelial apoptosis could contribute to tissue damage.

Compartment syndrome: pathophysiology, clinical presentations, treatment, and prevention in human and veterinary medicine

OBJECTIVE

To review the human and veterinary literature pertaining to all forms of compartment syndrome (CS).

DATA SOURCES

Data sources included scientific reviews and original research publications from the human and veterinary literature.

HUMAN DATA SYNTHESIS

While CS affecting the extremities has been recognized in people for decades, other forms of CS in the abdominal and thoracic cavities are recently gaining more attention. The role of CS in critically ill people is a rapidly growing area of interest. More research on prevention and treatment of CS is being conducted in people because some studies have found mortality rates as high as 80% for those suffering from these conditions.

VETERINARY DATA SYNTHESIS

While a significant amount of experimental studies of CS have been performed on small animals, there is a marked lack of primary veterinary studies. The majority of the veterinary literature includes case reports and series, and many of these studies were published over a decade ago. However, the increased recognition of CS in people has sparked an interest in veterinary critical care medicine and this has been demonstrated by the recent increased evaluation of compartment pressures in veterinary patients.

CONCLUSIONS

CS is a complex clinical condition where increased pressure within a compartment can cause significant adverse effects within the compartment as well as throughout the body. Systemic inflammatory responses and local ischemia-reperfusion elements can contribute to the detrimental effects seen in CS. This cascade of events results in increased mortality rates and contributes to the development of CS elsewhere. A better understanding of CS will help veterinarians improve patient care and outcome. Future studies on incidence, prevention, and treatment of CSs in the critical care patient are needed in veterinary medicine.

Role of combination of L-arginine and α-tocopherol in renal transplantation ischaemia/reperfusion injury: a randomized controlled experimental study in a rat model

What's known on the subject? and What does the study add? Renal ischaemia/reperfusion (I/R) injury is an inevitable consequence of kidney transplantation. It contributes to delayed graft function (DGF), acute renal failure and graft rejection. The present study investigates for the first time the impact of a combination of L-arginine and alpha tocopherol on the renal ischemia/reperfusion injury in a rodent model of kidney transplantation. We found that concomitant administration of L-arginine and α-tocopherol has a more protective effect and synergistic antioxidant effect on ischaemia/reperfusion injury in transplanted rat kidneys.

OBJECTIVES

To investigate the role of L-arginine and α-tocopherol in ischaemia/reperfusion injury in a kidney transplanted rat model.

MATERIALS AND METHODS

In total, 40 male Sprague-Dawley rats subjected to renal transplantation received FK506 (tacrolimus) to overcome early acute rejection episodes. Animals were divided randomly into four groups (ten rats each). Group I were treated with FK506 (2 mg/kg/bw/day) and served as the control group. Group II were treated with L-arginine 300 mg/kg/bw. Group III were treated with α-tocopherol 30 mg/kg/bw. Group IV were treated with L-arginine and α-tocopherol. Urine and blood samples were taken at 0 (before operation), 2, 7 and 14 days post-transplantation for estimation of urine sodium, creatinine, fractional excretion of sodium, serum creatinine, sodium and blood urea nitrogen. Histological examination and measurement of malondialdehyde in kidney tissues were also performed.

RESULTS

Serum creatinine and blood urea nitrogen significantly decreased in L-arginine and α-tocopherol, as well as combination groups, compared to the control group. Malondialdehyde was significantly decreased in the combination group compared to L-arginine and α-tocopherol alone. Histological examination of the control group showed that acute tubular necrosis was markedly decreased in transplanted kidneys treated with a combination of both L-arginine and α-tocopherol.

CONCLUSIONS

Concomitant administration of l-arginine and α-tocopherol has a more protective effect and synergistic antioxidant effect on ischaemia/reperfusion injury in transplanted rat kidneys.

The protective effects of ascorbic acid against renal ischemia-reperfusion injury in male rats

There is increasing evidence to suggest that toxic oxygen radicals play an essential role in the pathogenesis of ischemia/reperfusion (I/R) injury in the kidney. This study was designed to investigate the effects of ascorbic acid (AA) in I/R-induced renal injury in rats. Thirty two male Sprague-Dawley rats were divided equally into four groups: group 1 (control; dissection of the right renal pedicle without nephrectomy), group 2 (sham operated; unilateral nephrectomy), group 3 (I/R; unilateral nephrectomy + I/R); and group 4 (AA+I/R; unilateral nephrectomy and I/R treated with ascorbic acid, 250mg kg(-1) i.p., for one hour prior to ischemia). On the 15th day following nephrectomy, groups 3 and 4 were subjected to 45 min of renal pedicle occlusion followed by 3 h of reperfusion. At the end of the treatment period, kidney samples were taken for histological examination or determination of the renal malondialdehyde (MDA) and glutathione (GSH) levels. Serum creatinine, blood urea nitrogen (BUN), and lactate dehydrogenase (LDH) concentrations were measured for the evaluation of renal function. I/R caused a significant decrease in GSH level, which was accompanied with a significant increase in MDA level of kidney tissues. Similarly, serum BUN and creatinine levels, as well as LDH, were elevated in the I/R group as compared to the control group. In group four, AA treatment reversed all the changes in these biochemical indices, as well as histopathological alterations normally induced by I/R. The findings imply that reactive oxygen species play a causal role in I/R-induced renal injury, and that AA exerts renoprotective effects, probably by radical scavenging and antioxidant activities.

Protective effect of rutin on the ischemia/reperfusion induced damage in rat kidney

Reactive oxygen species (ROS) are suggested to participate in ischemia/reperfusion (I/R) injury in the kidney. This study was designed to investigate the effect of rutin, a bioflavonoid, in I/R induced renal injury. Wistar albino rats were unilaterally nephrectomized, and 2 wk later they were subjected to 45 min of left renal pedicle occlusion followed by 3h of reperfusion. Either rutin (1g/kg) or saline was administrated (i.p.) 1h prior to ischemia. At the end of the reperfusion period, kidney samples were taken for determination of renal malondialdehyde (MDA) and glutathione (GSH) levels, manganese-superoxide dismutase (MnSOD) activity and histological examination. Serum creatinine, blood urea nitrogen (BUN), and lactate dehydrogenase (LDH) concentrations were measured for the evaluation of renal function. I/R caused a significant decrease in GSH level and MnSOD activity, which was accompanied by a significant increase in MDA level of kidney tissues. Similarly, serum BUN and creatinine levels, as well as LDH were elevated in the I/R group compared with the control group. Pretreatment of rats with rutin (1g/kg/ i.p.) significantly attenuated renal dysfunction, reduced elevated MDA levels, and restored the depleted MnSOD activity and GSH levels. These beneficial changes in the biochemical parameters were also associated with parallel changes in histopathological appearance. These findings suggest that ROS play a causal role in I/R induced renal injury, and that rutin exerts renal-protective effects, probably by inhibiting ROS and antioxidant activities.

Diagnosis and treatment of a chronic atlanto-occipital subluxation in a dog

A 6-year-old Labrador retriever-cross was evaluated for an abnormal gait and head carriage 6 weeks after suffering trauma. The dog was presented with an ambulatory tetraparesis and was reluctant to move his head. Myelography and computed tomography demonstrated a subluxation of the atlanto-occipital joint with compression of the spinomedullary junction and the brain stem by the occipital bone. Removal of the compressive part of the occipital bone resulted in improvement of the clinical signs within 6 weeks, and resolution of clinical signs occurred 8 months after surgery.