Ellagic acid Alleviates hepatic ischemia-reperfusion injury in C57 mice via the Caspase-1-GSDMD pathway.

BACKGROUND: Ellagic acid (EA) has improving function against oxidative damage and inflammatory reaction in many disorders. Hepatic ischemia-reperfusion injury (IRI) is a common pathophysiological phenomenon in the veterinary clinic. In the present study, the protective effects of EA pretreatment against hepatic IRI-induced injury and the underlying mechanisms were investigated. RESULTS: We found that pyroptosis is involved in hepatic IRI, which is manifested in increasing the expression of pyroptosis-related genes and promoting the expression of active caspase-1, thereby cleaving GSDMD-N to cause pyroptosis, and caspase-1-/- mice were used to verify this conclusion. In addition, we found that EA protects against hepatic IRI by inhibiting pyroptosis, including reducing the activity of caspase-1 and its expression in the liver, inhibiting the lysis of GSDMD-N, and reducing the levels of IL-18 and IL-1ß. CONCLUSIONS: The present results have demonstrated that prophylactic administration of EA ameliorated hepatic IRI by inhibiting pyroptosis induced in hepatic ischemia-reperfusion in vivo through the caspase-1-GSDMD axis, providing a potential therapeutic option prevent hepatic IRI in pets.

Structure-function relationships of the soluble form of the antiaging protein Klotho have therapeutic implications for managing kidney disease.

The fortuitously discovered antiaging membrane protein αKlotho (Klotho) is highly expressed in the kidney, and deletion of the Klotho gene in mice causes a phenotype strikingly similar to that of chronic kidney disease (CKD). Klotho functions as a co-receptor for fibroblast growth factor 23 (FGF23) signaling, whereas its shed extracellular domain, soluble Klotho (sKlotho), carrying glycosidase activity, is a humoral factor that regulates renal health. Low sKlotho in CKD is associated with disease progression, and sKlotho supplementation has emerged as a potential therapeutic strategy for managing CKD. Here, we explored the structure-function relationship and post-translational modifications of sKlotho variants to guide the future design of sKlotho-based therapeutics. Chinese hamster ovary (CHO)- and human embryonic kidney (HEK)-derived WT sKlotho proteins had varied activities in FGF23 co-receptor and ß-glucuronidase assays in vitro and distinct properties in vivo Sialidase treatment of heavily sialylated CHO-sKlotho increased its co-receptor activity 3-fold, yet it remained less active than hyposialylated HEK-sKlotho. MS and glycopeptide-mapping analyses revealed that HEK-sKlotho is uniquely modified with an unusual N-glycan structure consisting of N,N'-di-N-acetyllactose diamine at multiple N-linked sites, one of which at Asn-126 was adjacent to a putative GalNAc transfer motif. Site-directed mutagenesis and structural modeling analyses directly implicated N-glycans in Klotho's protein folding and function. Moreover, the introduction of two catalytic glutamate residues conserved across glycosidases into sKlotho enhanced its glucuronidase activity but decreased its FGF23 co-receptor activity, suggesting that these two functions might be structurally divergent. These findings open up opportunities for rational engineering of pharmacologically enhanced sKlotho therapeutics for managing kidney disease.

Ischaemic postconditioning reduces apoptosis in experimental jejunal ischaemia in horses.

BACKGROUND: Ischaemic postconditioning (IPoC) refers to brief periods of reocclusion of blood supply following an ischaemic event. This has been shown to ameliorate ischaemia reperfusion injury in different tissues, and it may represent a feasible therapeutic strategy for ischaemia reperfusion injury following strangulating small intestinal lesions in horses. The objective of this study was to assess the degree cell death, inflammation, oxidative stress, and heat shock response in an equine experimental jejunal ischaemia model with and without IPoC. METHODS: In this randomized, controlled, experimental in vivo study, 14 horses were evenly assigned to a control group and a group subjected to IPoC. Under general anaesthesia, segmental ischaemia with arterial and venous occlusion was induced in 1.5 m jejunum. Following ischaemia, the mesenteric vessels were repeatedly re-occluded in group IPoC only. Full thickness intestinal samples and blood samples were taken at the end of the pre-ischaemia period, after ischaemia, and after 120 min of reperfusion. Immunohistochemical staining or enzymatic assays were performed to determine the selected variables. RESULTS: The mucosal cleaved-caspase-3 and TUNEL cell counts were significantly increased after reperfusion in the control group only. The cleaved-caspase-3 cell count was significantly lower in group IPoC after reperfusion compared to the control group. After reperfusion, the tissue myeloperoxidase activity and the calprotectin positive cell counts in the mucosa were increased in both groups, and only group IPoC showed a significant increase in the serosa. Tissue malondialdehyde and superoxide dismutase as well as blood lactate levels showed significant progression during ischaemia or reperfusion. The nuclear immunoreactivity of Heat shock protein-70 increased significantly during reperfusion. None of these variables differed between the groups. The neuronal cell counts in the myenteric plexus ganglia were not affected by the ischaemia model. CONCLUSIONS: A reduced apoptotic cell count was found in the group subjected to IPoC. None of the other tested variables were significantly affected by IPoC. Therefore, the clinical relevance and possible protective mechanism of IPoC in equine intestinal ischaemia remains unclear. Further research on the mechanism of action and its effect in clinical cases of strangulating colic is needed.

Elevated Serum Potassium Concentration Alleviates Cerebral Ischemia-Reperfusion Injury via Mitochondrial Preservation.

BACKGROUND/AIMS: The anti-apoptotic effect of an increase in the extracellular concentration of potassium ([K+]) has been confirmed in vitro. However, it is not yet known whether elevated serum [K+] exerts a cerebroprotective effect in vivo. In this study, we aimed to explore the effect of elevated serum [K+] in a rat model of middle cerebral artery occlusion and reperfusion (MCAO/R). METHODS: Rats subjected to 90-min MCAO received 2.5% KCL, 1.25% KCL, or a normal saline solution at a dose of 3.2 mL/kg at the onset of reperfusion. Rats that were subjected to vascular exposure and ligation without MCAO were defined as the Sham group. Serum [K+] was determined using a blood gas analyzer at 1 min after medicine administration. At 24 h post-reperfusion, rat brains were harvested and processed for 2% 2,3,5-triphenyltetrazolium chloride staining, terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick end labeling staining, detection of caspase-3 and cleaved-caspase-3 by western blotting, detection of reactive oxygen species (ROS) by dihydroethidium staining, and observation of mitochondrial structure by electron microscopy. In addition, malondialdehyde (MDA), adenosine triphosphate (ATP), total superoxide dismutase (T-SOD), cytochrome C oxidase (COX) activity, and mitochondrial permeability transition pore (MPTP) opening were measured using detection kits. RESULTS: The results showed that elevated serum [K+] decreased cerebral injury and apoptosis, reduced ROS and MDA levels and MPTP opening, increased ATP levels and cytochrome C oxidase activity, and improved mitochondrial ultrastructural changes, although there was no significant difference in T-SOD activity. CONCLUSION: These findings suggested that elevated serum [K+] could alleviate cerebral ischemia-reperfusion injury and the mechanism may be associated with the preservation of mitochondrial function.

Liver transplantation in the mouse: Insights into liver immunobiology, tissue injury, and allograft tolerance.

The surgically demanding mouse orthotopic liver transplant model was first described in 1991. It has proved to be a powerful research tool for the investigation of liver biology, tissue injury, the regulation of alloimmunity and tolerance induction, and the pathogenesis of specific liver diseases. Liver transplantation in mice has unique advantages over transplantation of the liver in larger species, such as the rat or pig, because the mouse genome is well characterized and there is much greater availability of both genetically modified animals and research reagents. Liver transplant experiments using various transgenic or gene knockout mice have provided valuable mechanistic insights into the immunobiology and pathobiology of the liver and the regulation of graft rejection and tolerance over the past 25 years. The molecular pathways identified in the regulation of tissue injury and promotion of liver transplant tolerance provide new potential targets for therapeutic intervention to control adverse inflammatory responses/immune-mediated events in the hepatic environment and systemically. In conclusion, orthotopic liver transplantation in the mouse is a valuable model for gaining improved insights into liver biology, immunopathology, and allograft tolerance that may result in therapeutic innovation in the liver and in the treatment of other diseases.

Urinary neutrophil gelatinase-associated lipocalin concentration changes after acute haemorrhage and colloid-mediated reperfusion in anaesthetized dogs.

OBJECTIVE: To determine changes in urine neutrophil gelatinase-associated lipocalin concentration (uNGAL) in anaesthetized Greyhound dogs that developed acute tubular damage following haemorrhage and resuscitation with colloid-based fluids. STUDY DESIGN: Prospective experimental study. ANIMALS: Seven healthy adult entire male Greyhound dogs. METHODS: During isoflurane anaesthesia, approximately 50 mL kg(-1) of blood was removed to maintain mean arterial pressure (MAP) ≤40 mmHg for 1 hour followed by gelatin-based colloid administration to maintain MAP ≥60 mmHg for 3 hours. Data, including oxygen extraction ratio and uNGAL, were collected before (T0) and immediately following (T1) haemorrhage, and hourly during reperfusion (T2-T4). After T4, dogs were euthanized and renal tissue was collected for histology. Statistical analysis was performed using repeated-measures one-way anova. Data are presented as means (95% confidence interval). RESULTS: Histology identified renal tubular epithelial damage in all dogs. Urine NGAL concentration increased from 12.1 (0-30.6) ng mL(-1) at T0 to 122.0 (64.1-180.0) ng mL(-1) by T3. Compared with T0, uNGAL was significantly higher at T3 (p = 0.016) and was increased 24-fold. CONCLUSIONS AND CLINICAL RELEVANCE: Despite wide individual variation in baseline uNGAL, increases in uNGAL were observed in all dogs, suggesting that this biomarker has the potential to detect renal tubular injury following haemorrhage-induced hypotension and colloid-mediated reperfusion.

Kidney/Aorta Ratio for Renal Morphometric Determination in Swine Subjected to Acute Kidney Injury Using an Optimized Surgical Model.

This research aims to establish an experimental surgical model for access to the renal pedicle and kidney and to determine renal length measurement via the kidney/aorta ratio (K/AO) using ultrasound. Fifteen swine underwent ventral median celiotomy with a supraumbilical transverse incision to access the right and left renal pedicles and induce renal ischemia-reperfusion injury (IRR). The kidneys were evaluated using ultrasonography to standardize renal length, aortic diameter, and the K/AO. Assessment was performed at 2 time points: 1 h before and 24 h after the surgery to induce IRR. Blood and urine samples were collected to assess renal function. Histologic evaluation of kidney fragments was also conducted. The proposed abdominal cavity access method proved to be highly efficient for exposing the right and left renal pedicles and inducing IRR. Serum levels of urea, creatinine, calcium, and phosphorus, as well as levels of the urinary protein/urinary creatinine ratio and urinary GGT, did not show significant differences. Acute kidney injury was confirmed through histopathology. The mean lengths of the right and left kidneys were 82.63 and 87.64 mm, respectively. The values of the right and left K/AO were 9.81 and 10.38, respectively. There was no statistically significant difference in the K/AO ratio before and after IRR. The proposed surgical model allowed surgical intervention on the renal pedicles without intra- or postoperative complications. Furthermore, the K/AO could be measured through ultrasonography, establishing a reference for healthy animals.

Dexmedetomidine preconditioning reduces ischaemia-reperfusion injury in equine model of large colon volvulus.

BACKGROUND: Large colon volvulus is a cause of colic in horses with high morbidity and mortality when not promptly treated. More treatment options are needed to improve the outcome of these cases by protecting against the damage caused by ischaemia and reperfusion injury. OBJECTIVES: To determine the effect of preconditioning with dexmedetomidine prior to induction of ischaemia-reperfusion (IR) injury in a large colon volvulus model in the horse. STUDY DESIGN: Randomised blinded in vivo experiments. METHODS: Horses received either a dexmedetomidine (DEX) or saline (CON) constant rate infusion (CRI) immediately following induction of anaesthesia. Venous, arterial, and transmural occlusion of a section of the large colon was performed for 3 h, after which the ligatures and clamps were removed to allow for reperfusion for 3 h. Biopsies of the large colon were taken at baseline, 1 and 3 h of ischaemia, and at 1 and 3 h of reperfusion. RESULTS: The severity of crypt epithelial loss (DEX = 2.1 [0.8-2.8], CON = 3.1 [2.5-4], p = 0.03) and mucosal haemorrhage was decreased (DEX = 2.1 [1.3-3], CON = 3.5 [2.5-4], p = 0.03) in group DEX compared to group CON when graded on a scale of 0-4. Crypt length remained longer (DEX = 369.5 ± 91.7 µm, CON = 238.5 ± 72.6 µm, p = 0.02) and interstitium to crypt (I:C) ratio remained lower (DEX = 1.4 (1-1.7), CON = 2.6 [1.8-5.9], p = 0.03) in group DEX compared to group CON during reperfusion. MAIN LIMITATIONS: Clinical applicability of pharmacologic preconditioning is limited. CONCLUSION: Preconditioning with a dexmedetomidine CRI prior to IR injury demonstrated a protective effect histologically on the large colon in the horse. Further investigation into postconditioning with dexmedetomidine is warranted as a possible intervention in colic cases suspected of being large colon volvulus.

Protective effectiveness of anise against testicular ischemia and reperfusion injury: An experimental study in rats.

Testicular torsion is a frequently encountered clinical condition that requires urgent treatment. The aim of this study is to investigate the efficacy of Anise (Pimpinella anisum L.) in treating the pathological condition due to ischemia and reperfusion injury by using biochemical, histopathological and immunohistochemical methods. A total of 6 groups were formed with 8 male Wistar Albino rats in each group. Group 1 (n=8): control group, Group 2 (n=8): Anise aqueous solution was given orally 5 ml/kg by gavage for 30 days. Group 3 (n=8): Ischemia and Reperfusion (I/R) group, bilateral testicles were rotated 270° and reperfused after 30 minutes of ischemia. Group 4 (n=8): I/R+ Anise group, Group 5 (n=8): Anise+ I/R group and Group 6 (n=8): Anise+ I/R+ Anise group. The results of the Anise group and the Control group were similar. However, the damage in the I/R group was considerably more severe than in any of the other study groups. While it was observed that spermatogenic cells started to regenerate in the I/R+Anise group, edema and congestion were observed in the Anise+I/R group. In the Anise+I/R+Anise group, all histological findings and biochemical parameters were similar to those of the control group. It was observed that anise had protective effects in ischemia and reperfusion injury in rat testicles.

Protective effects of anise in prevention of cerebral ischemia reperfusion injury in rats.

The aim of this study is to determine the protective efficacy of anise in cerebral ischemia and reperfusion injury in rats. In this study, 28 Wistar Albino rats, weighing 250-300 grams (g), were used. Four groups were formed with 7 rats in each group. Group 1 (n=7): Control group, Group 2 (n=7): Anise group, 5 mL/kg/day of anise aqueous extract prepared according to Gamberini's protocol was given orally by gavage for 30 days. Group 3 (n=7): Cerebral ischemia reperfusion (CIR) group, at the beginning of the experiment, 30 minutes of cerebral ischemia and 1 hour of reperfusion were induced and the animals were sacrificed by exanguination. Group 4 (n=7): Anise+ CIR group, After administering 30 days of anise's aqueous extract, CIR was induced and the study was terminated. TOS values of the Anise+ CIR group was significantly lower than that of the CIR group (p<0.05). Il-6 and TNF-α values of the CIR group were significantly higher than the Anise+ CIR group (p<0,05). Our study revealed that anise ameliorates oxidative damage and inflammation due to cerebral ischemia/reperfusion, by reducing the levels of inflammatory cytokines (TNF-α, Il-6).

Adipose-derived mesenchymal stem cells secrete extracellular vesicles: A potential cell-free therapy for canine renal ischaemia-reperfusion injury.

BACKGROUND: Adipose-derived mesenchymal stem cells (ADMSCs) and their extracellular vesicles (EVs) are a promising source of therapies for ischaemia-reperfusion (IR) because of their potent anti-inflammatory and immunomodulatory properties. OBJECTIVES: The aims of this study were to explore the therapeutic efficacy and potential mechanism of ADMSC-EVs in canine renal IR injury. METHODS: Mesenchymal stem cells (MSCs) and EVs were isolated and characterised for surface markers. A canine IR model administered with ADMSC-EVs was used to evaluate therapeutic effects on inflammation, oxidative stress, mitochondrial damage and apoptosis. RESULTS: CD105, CD90 and beta integrin ITGB were positively expressed in MSCs, while CD63, CD9 and intramembrane marker TSG101 were positively expressed in EVs. Compared with the IR model group, there was less mitochondrial damage and reduction in quantity of mitochondria in the EV treatment group. Renal IR injury led to severe histopathological lesions and significant increases in biomarkers of renal function, inflammation and apoptosis, which were attenuated by the administration of ADMSC-EVs. CONCLUSIONS: Secretion of EVs by ADMSCs exhibited therapeutic potential in renal IR injury and may lead to a cell-free therapy for canine renal IR injury. These findings revealed that canine ADMSC-EVs potently attenuate renal IR injury-induced renal dysfunction, inflammation and apoptosis, possibly by reducing mitochondrial damage.

Ischemic preconditioning reduces endoplasmic reticulum stress and upregulates hypoxia inducible factor-1α in ischemic kidney: the role of nitric oxide.

BACKGROUND: Although recent studies indicate that renal ischemic preconditioning (IPC) protects the kidney from ischemia-reperfusion (I/R) injury, the precise protective mechanism remains unclear. In the current study, we investigated whether early IPC could upregulate hypoxia inducible transcription factor-1α (HIF-1α) expression and could reduce endoplasmic reticulum (ER) stress after renal I/R and whether pharmacological inhibition of nitric oxide (NO) production would abolish these protective effects. METHODS: Kidneys of Wistar rats were subjected to 60 min of warm ischemia followed by 120 min of reperfusion (I/R group), or to 2 preceding cycles of 5 min ischemia and 5 min reperfusion (IPC group), or to intravenously injection of NG-nitro-L-arginine methylester (L-NAME, 5 mg/kg) 5 min before IPC (L-NAME+IPC group). The results of these experimental groups were compared to those of a sham-operated group. Sodium reabsorption rate, creatinine clearance, plasma lactate dehydrogenase (LDH) activity, tissues concentrations of malonedialdehyde (MDA), HIF-1α and nitrite/nitrate were determined. In addition, Western blot analyses were performed to identify the amounts of Akt, endothelial nitric oxide synthase (eNOS) and ER stress parameters. RESULTS: IPC decreased cytolysis, lipid peroxidation and improved renal function. Parallelly, IPC enhanced Akt phosphorylation, eNOS, nitrite/nitrate and HIF-1α levels as compared to I/R group. Moreover, our results showed that IPC increased the relative amounts of glucose-regulated protein 78 (GRP78) and decreased those of RNA activated protein kinase (PKR)-like ER kinase (PERK), activating transcription factor 4 (ATF4) and TNF-receptor-associated factor 2 (TRAF2) as judged to I/R group. However, pre treatment with L-NAME abolished these beneficial effects of IPC against renal I/R insults. CONCLUSION: These findings suggest that early IPC protects kidney against renal I/R injury via reducing oxidative and ER stresses. These effects are associated with phosphorylation of Akt, eNOS activation and NO production contributing thus to HIF-1α stabilization. The beneficial impact of IPC was abolished when NO production is inhibited before IPC application.

The effect of ischaemic postconditioning on mucosal integrity and function in equine jejunal ischaemia.

BACKGROUND: Ischaemic postconditioning (IPoC) has been shown to ameliorate ischaemia reperfusion injury in different species and tissues. OBJECTIVES: To assess the feasibility of IPoC in equine small intestinal ischaemia and to assess its effect on histomorphology, electrophysiology and paracellular permeability. STUDY DESIGN: Randomised in vivo experiment. METHODS: Experimental jejunal ischaemia was induced for 90 min in horses under general anaesthesia. In the control group (C; n = 7), the jejunum was reperfused without further intervention. In the postconditioning group (IPoC; n = 7), reocclusion was implemented following release of ischaemia by clamping the mesenteric vessels in three cycles of 30 seconds. This was followed by 120 minutes of reperfusion in both groups. Intestinal microperfusion and oxygenation was measured during IPoC using spectrophotometry and Doppler flowmetry. Histomorphology and histomorphometry of the intestinal mucosa were assessed. Furthermore, electrophysiological variables and unidirectional flux rates of 3 H-mannitol were determined in Ussing chambers. Western blot analysis was performed to determine the tight junction protein levels of claudin-1, claudin-2 and occludin in the intestinal mucosa. Comparisons between the groups and time points were performed using a two-way repeated measures analysis of variance (ANOVA) or non-parametric statistical tests for the ordinal and not normally distributed data (significance P < .05). RESULTS: IPoC significantly reduced intestinal microperfusion during all clamping cycles yet affected oxygen saturation only during the first cycle. After reperfusion, Group IPoC showed significantly less mucosal villus denudation (mean difference 21.5%, P = .02) and decreased mucosal-to-serosal flux rates (mean difference 15.2 nM/cm2 /h, P = .007) compared to Group C. There were no significant differences between the groups for the other tested variables. MAIN LIMITATIONS: Small sample size, long-term effects were not investigated. CONCLUSIONS: Following IPoC, the intestinal mucosa demonstrated significantly less villus denudation and paracellular permeability compared to the untreated control group, possibly indicating a protective effect of IPoC on ischaemia reperfusion injury.

Protective effects of crocin on testicular torsion/detorsion in rats.

Oxidative stress, caused by extreme accumulation of un-scavenged reactive oxygen species, plays an integral role in the Ischemia-Reperfusion (I/R) injury to the testicles following testicular torsion. The current research aimed to examine the protective effects of crocin as a natural antioxidant on testicular I/R injury in rats. Animals were divided randomly into five groups (seven each): (1) sham group, (2) torsion/detorsion (T/D) group, (3) intact group with 100 mg/kg crocin, (4) and (5) T/D groups followed by treatment with two different doses of crocin (50 and 100 mg/kg (IP)). I/R injury was induced by 720° clockwise torsion of the left testicles for 2 h. After 24 h of reperfusion, blood samples and epididymal sperms were collected to measure biochemical (GPx, SOD, and MDA), hormonal (testosterone), and sperm parameters (total sperm recovery, motility, viability, and morphology). Moreover, affected testicles were subjected to histopathology examination. I/R injury caused a significant reduction in sperm characteristics (except for morphology) (P < 0.05), which could not be significantly improved by crocin administration at either dose (P > 0.05). Johnsen's testicular score, mean seminiferous tubular diameter, and germinal epithelial cell thickness were significantly decreased in the T/D group compared to the intact and sham groups. However, crocin could significantly improve the histopathological parameters in both treatment groups compared to the T/D group (P < 0.05). T/D reduced SOD and GPx activity and testosterone level significantly (except for GPx) compared to the sham group (P < 0.05). However, crocin administration could significantly reverse them. Also, crocin reduced the amount of MDA significantly in the high-dose treatment group in comparison to T/D group (P < 0.05). The results of the current study revealed that crocin could be a promising agent to protect against I/R injury following surgical correction of the testicular torsion.

Protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in horses.

BACKGROUND: Strangulating small intestinal lesions in the horse have increased morbidity and mortality compared to nonstrangulating obstructions due to mucosal barrier disruption and subsequent endotoxaemia. OBJECTIVES: To investigate protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in the horse. STUDY DESIGN: Randomised, controlled, experimental study. METHODS: Eighteen systemically healthy horses were randomly assigned to three groups: control, preconditioning, and post-conditioning. During isoflurane anaesthesia, complete ischaemia was induced in a 1-m segment of jejunum for 90 minutes. Horses in the preconditioning and post-conditioning groups received dexmedetomidine (3.5 µg/kg followed by 7 µg/kg/h) before (preconditioning) or after beginning ischaemia (post-conditioning), and during reperfusion. Jejunal biopsies were collected before ischaemia (baseline-1), at the end of the ischaemic period (ischaemia), and 30 minutes after reperfusion (reperfusion-1). Additional biopsies were taken 24 hours after reperfusion from ischaemia-reperfusion-injured jejunum (reperfusion-2). Epithelial injury was scored histologically, and morphometric analyses were used to calculate villus surface area (VSA) denuded of epithelium. Data were analysed using analysis of variance, Kruskal-Wallis and Wilcoxon two-sample tests. RESULTS: In the control group, epithelial injury scores and percentage of VSA denudation for ischaemia-reperfusion-injured jejunum were higher compared to baseline-1 at all time points. The ischaemia and both reperfusion samples from the pre- and post-conditioning groups had lower epithelial injury scores and percentage of VSA epithelial denudation compared to the control group, with no difference from baseline-1 at any time point for the preconditioning group. MAIN LIMITATIONS: Preconditioning has limited application in the clinical setting with naturally occurring strangulating small intestinal lesions. CONCLUSIONS: Dexmedetomidine was protective for small intestinal ischaemia-reperfusion injury in the horse when administered before or during ischaemia.

Preconditioning with lidocaine and xylazine in experimental equine jejunal ischaemia.

BACKGROUND: Pharmacological preconditioning of dexmedetomidine on small intestinal ischaemia/reperfusion injury has been reported in different animal models including horses. OBJECTIVES: The objective was to assess if xylazine and lidocaine have a preconditioning effect in an experimental model of equine jejunal ischaemia. STUDY DESIGN: Terminal in vivo experiment. METHODS: Ten horses under general anaesthesia were either preconditioned with xylazine (group X; n = 5) or lidocaine (group L; n = 5). A historical untreated control group (group C; n = 5) was used for comparison. An established experimental model of equine jejunal ischaemia was applied, and intestinal samples were taken pre-ischaemia, after ischaemia and following reperfusion. Histomorphological examination was performed based on a modified Chiu score. Immunohistochemical staining for cleaved caspase-3, TUNEL and calprotectin was performed, and positive cell counts were expressed in cells/mm2 . RESULTS: There was no progression of histomorphological mucosal injury from ischaemia to reperfusion, and there were no differences in histomorphology between the groups. After ischaemia, group X had significantly less caspase-positive cells compared to the control group with a median difference of 227% (P = .01). After reperfusion, group X exhibited significantly lower calprotectin-positive cell counts compared to the control group, with a median difference of 6.8 cells/mm2 in the mucosa and 44 cells in the serosa (P = .02 and .05 respectively). All groups showed an increase in caspase- and calprotectin-positive cells during reperfusion (P < .05). TUNEL-positive cells increased during ischaemia, followed by a decrease after reperfusion (P < .05). MAIN LIMITATIONS: The small sample size and the use of a historical control group. Preconditioning effects of the tested drugs may be masked by the protective effects of isoflurane in the anaesthetic protocol. CONCLUSIONS: Preconditioning with lidocaine did not have any effect on the tested variables. The lower cell counts of caspase- and calprotectin-positive cells in group X may indicate a beneficial effect of xylazine on ischaemia/reperfusion injury. Due to the absence of a concurrent reduction of histomorphological injury, the clinical significance remains uncertain.

The clinical efficacy of pentoxifylline and l-glutamine on ischemia and reperfusion injury in cattle with displaced abomasum: a longitudinal study.

This study aimed to assess the clinical efficacy of pentoxifylline (PTX) and L-glutamine (L-Gln) treatment on ischemia and reperfusion (I/R) injury in the abomasal tissue, acute phase response (APR), oxidative stress (OS), cytokine response, hemostatic, and coagulation disorders in the 96-h period before and after surgery in displaced abomasum (DA) cases. The study sample consisted of 48 dairy cows with DA that were categorized into four groups as group S (Sham group) (9 Left displaced abomasum (LDA)+3 Right displaced abomasum (RDA), group P (PTX) (10 LDA+2 RDA), group G (L-Gln) (10 LDA+2 RDA), and group P+G (PTX+L-Gln) (10 LDA+2 RDA). Acute-phase protein (Haptoglobin), oxidative stress indicators (malondialdehyde, nitric oxide, and glutathione), cytokines (tumor necrosis factor (TNF)-α and interleukin-1ß (IL-1ß), coagulation factors (D-Dimer, Antithrombin (ATIII), Thrombin-antithrombin complex, Plasminogen activator inhibitor-1), and enzyme activities (lactate dehydrogenase, gamma- -glutamyl transferase, sorbitol dehydrogenase, glutamate dehydrogenase, adenosine deaminase, myeloperoxidase, and creatine phosphokinase) in blood serum samples and coagulometric analyses of blood plasma were performed in samples taken before the operation and at 30 and 60 min and 2, 5, 10, 24, 48, 72, and 96 h after the operation. In DA cases, while post-operative treatment procedures with PTX and L-Gln were effective in decreasing APR and OS, these were ineffective in prohibiting the inflammatory response coordinated by cytokines. For the treatment and prevention of I/R injury in the DA cases, PTX and L-Gln procedures hold promise with their effects on APR, OS, and hemostatic dysfunction. Additional treatment procedures are required for the suppression of inflammatory response, and the effectiveness of preconditioning treatment may be evaluated.

Ability of different assay platforms to measure renal biomarker concentrations during ischaemia-reperfusion acute kidney injury in dogs.

Several protein biomarkers have been shown to be useful for the early diagnosis of acute kidney injury (AKI) in animals and people. Multiplex assays for measurement of a panel of renal biomarkers in canine samples have recently become available. This study compared the use of two such assays, versus previously validated ELISAs, to measure five biomarkers in canine samples during ischaemia-reperfusion (IR) AKI. Blood and urine was collected from six male anaesthetised greyhounds that underwent 1-h of renal ischaemia (severe hypotension induced by acute haemorrhage) and 2-h of reperfusion (intravenous fluid resuscitation). Histology confirmed presence of acute tubular injury at 2 h of reperfusion. Concentrations of clusterin, cystatin C, kidney-injury molecule 1 (KIM-1), monocyte chemoattractant protein 1, and neutrophil gelatinase-associated lipocalin (NGAL) at baseline and following IR, measured by two different multiplex assays and previously-validated single analyte immunoassays, were compared. Only NGAL was significantly elevated following IR with all assays investigated. Whether concentrations of the other four biomarkers were significantly increased following IR depended on the assay used. Concentrations of cystatin C and KIM-1 measured with the multiplex assays were of a vast magnitude lower than those measured with the corresponding single analyte ELISAs. We conclude that further validation is required before these assays can reliably be used to measure AKI biomarkers in canine samples.

In vitro effects of lidocaine on the contractility of equine jejunal smooth muscle challenged by ischaemia-reperfusion injury.

REASONS FOR PERFORMING STUDY: Post operative ileus (POI) in horses is a severe complication after colic surgery. A commonly used prokinetic drug is lidocaine, which has been shown to have stimulatory effects on intestinal motility. The cellular mechanisms through which lidocaine affects smooth muscle activity are not yet known. OBJECTIVES: To examine the effects of lidocaine on smooth muscle in vitro and identify mechanisms by which it may affect the contractility of intestinal smooth muscle. HYPOTHESIS: Ischaemia and reperfusion associated with intestinal strangulation can cause smooth muscle injury. Consequently, muscle cell functionality and contractile performance is decreased. Lidocaine can improve basic cell functions and thereby muscle cell contractility especially in ischaemia-reperfusion-challenged smooth muscle. METHODS: To examine the effects of lidocaine on smooth muscle function directly, isometric force performance was measured in vitro in noninjured and in vivo ischaemia-reperfusion injured smooth muscle tissues. Dose-dependent response of lidocaine was measured in both samples. To assess membrane permeability as a marker of basic cell function, release of creatine kinase (CK) was measured by in vitro incubations. RESULTS: Lidocaine-stimulated contractility of ischaemia-reperfusion injured smooth muscle was more pronounced than that of noninjured smooth muscle. A 3-phasic dose-dependency was observed with an initial recovery of contractility especially in ischaemia-reperfusion injured smooth muscle followed by a plateau phase where contractility was maintained over a broad concentration range. CK release was decreased by lidocaine. CONCLUSION: Lidocaine may improve smooth muscle contractility and basic cell function by cellular repair mechanisms which are still unknown. Improving contractility of smooth muscle after ischaemia-reperfusion injury is essential in recovery of propulsive intestinal motility. POTENTIAL RELEVANCE: Characterisation of the cellular mechanisms of effects of lidocaine, especially on ischaemia-reperfusion injured smooth muscle, may lead to improved treatment strategies for horses with POI.

Erdosteine in renal ischemia-reperfusion injury: an experimental study in pigs.

The aim of the present study was to investigate the effect of erdosteine on renal reperfusion injury. Twelve male Landrace and Yorkshire mixed pigs were randomly divided into two groups: untreated control group (I/R), erdosteine treated group (I/R + erdosteine). Each group is composed of six pigs, and the pigs were unilaterally nephrectomized and their contralateral kidneys were subjected to 30 min of renal pedicle occlusion. The elevations of creatinine and blood urea nitrogen levels were lower in the treated group compared with the control group. The catalase activity and the glutathione peroxidase activity were higher in the erdosteine group. As a result, this study suggests that the erdosteine treatment has a role of attenuation of renal I/R injury recovery of renal function in pig.