Ischemic preconditioning attenuates remote pulmonary inflammatory infiltration of diabetic rats with an intestinal and hepatic ischemia-reperfusion injury

Protective effect of remote liver ischemic postconditioning on pulmonary ischemia and reperfusion injury in diabetic and non-diabetic rats

Pulmonary ischemia and reperfusion (I/R) injury occurs in many clinical conditions and causes severe damage to the lungs. Diabetes mellitus (DM) predisposes to pulmonary I/R injury. We previously found that remote liver ischemia preconditioning protected lungs against pulmonary I/R injury. The aim of the present study was to investigate whether remote liver ischemic postconditioning (RLIPost) attenuates pulmonary damage induced by I/R injury in non-diabetic or diabetic rats. Male Sprague-Dawley rats were assigned into non-diabetic and diabetic groups. All rats except for the sham were exposed to 45 min of left hilum occlusion followed by 2 h of reperfusion. RLIPost was conducted at the onset of pulmonary reperfusion by four cycles of 5 min of liver ischemia and reperfusion. Lung injury was assessed by the wet/dry weight ratio, pulmonary oxygenation, histopathological changes, apoptosis and the expression of inflammatory cytokines. Reperfusion-associated protein phosphorylation states were determined. RLIPost offered strong pulmonary-protection in both non-diabetic and diabetic rats, as reflected in reduced water content and pulmonary structural damage, recovery of lung function, inhibition of apoptosis and inflammation after ischemia-reperfusion. RLIPost induced the activation of pulmonary STAT-3, a key component in the SAFE pathway, but not activation of the proteins in the RISK pathway, in non-diabetic rats. In contrast, RLIPost-induced pulmonary protection in diabetic lungs was independent of SAFE or RISK pathway activation. These results demonstrate that RLIPost exerts pulmonary protection against I/R-induced lung injury in non-diabetic and diabetic rats. The underlying mechanism for protection may be different in non-diabetic (STAT-3 dependent) versus diabetic (STAT-3 independent) rats.

Pro-inflammatory cytokines/chemokines, TNF-α, IL-6 and MCP-1, as biomarkers for the nephro- and pneumoprotective effect of silibinin after hepatic ischemia/reperfusion: confirmation by immunihistochemistry and qRT-PCR

The present study investigated the potential nephro- and pneumoprotective effect of silibinin (Si) after hepatic ischemia-reperfusion (I/R) injury, by measuring pro-inflammatory factors. Sixty-three rats were randomly assigned into three groups, as follows: (a) the sham group (n=7 rats), subjected to opening and closing the abdomen; (b) the control group (n = 28 rats), subjected to 45-min hepatic ischemia followed by reperfusion; and (c) the silibinin group (n=28), subjected to 45-min hepatic ischemia followed by intravenous administration of lyophilized SLB-HP-β-CD before reperfusion. Control and silibinin groups were further subdivided into time-point groups, according to the duration of reperfusion. TNF-α, IL-6 and MCP-1 expressions were determined immunihistochemically and by qrT-PCR at each time-point. Kidney TNF-α expression was significantly lower at 180 and 240 min, while lung TNF-α expression was significantly lower at 240 min. Comparison between the control and Si group at the same time-points, showed very strong evidence of difference at 240 min, with the levels of IL-6 shifting towards lower values in the Si group. Finally, we found a high MCP-1 expression after 120 min. We conclude that hepatic I/R injury remotely increases proinflammatory mediators in the kidney and lung, whereas silibinin shows a time-dependent nephro- and pneumoprotective effect.

The effects of ischaemic conditioning on lung ischaemia-reperfusion injury

Ischaemia-reperfusion injury (IRI) encompasses the deleterious effects on cellular function and survival that result from the restoration of organ perfusion. Despite their unique tolerance to ischaemia and hypoxia, afforded by their dual (pulmonary and bronchial) circulation as well as direct oxygen diffusion from the airways, lungs are particularly susceptible to IRI (LIRI). LIRI may be observed in a variety of clinical settings, including lung transplantation, lung resections, cardiopulmonary bypass during cardiac surgery, aortic cross-clamping for abdominal aortic aneurysm repair, as well as tourniquet application for orthopaedic operations. It is a diagnosis of exclusion, manifesting clinically as acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Ischaemic conditioning (IC) signifies the original paradigm of treating IRI. It entails the application of short, non-lethal ischemia and reperfusion manoeuvres to an organ, tissue, or arterial territory, which activates mechanisms that reduce IRI. Interestingly, there is accumulating experimental and preliminary clinical evidence that IC may ameliorate LIRI in various pathophysiological contexts. Considering the detrimental effects of LIRI, ranging from ALI following lung resections to primary graft dysfunction (PGD) after lung transplantation, the association of these entities with adverse outcomes, as well as the paucity of protective or therapeutic interventions, IC holds promise as a safe and effective strategy to protect the lung. This article aims to provide a narrative review of the existing experimental and clinical evidence regarding the effects of IC on LIRI and prompt further investigation to refine its clinical application.

Effects of remifentanil and propofol on distant organ lung injury in an ischemia-reperfusion model

Our aim was to evaluate lung injury due to oxidative stress and antioxidant activity levels in an infrarenal ischemia-reperfusion model and to compare prevention effects of single and combined use of propofol and remifentanil. In this study, a total of 40 adult Wistar Albino rats were randomly divided into five groups of eight rats as SHAM, physiological saline, intraperitoneal propofol, remifentanil, and propofol and remifentanil groups. Blood and tissue samples were obtained after 80 min of reperfusion. The malondialdehyde (MDA) level, a measure of lipid peroxidation, was measured in lung tissue samples and red blood cells; additionally, total oxidant status and total antioxidant capacity of lung tissues were measured and histopathological examination was performed. Distant organ (lung) injury developed due to lower extremity ischemia-reperfusion was created by infrarenal aortic clamping. The lipid peroxidation product MDA and total oxidant levels were increased, but there was insufficient antioxidant protection both in the lung tissues and red blood cells. While propofol prevented this injury consistent with its proposed antioxidant properties; no protective effect of remifentanil was observed. On the contrary, it showed oxidative stress increasing effect. This study concluded that the antioxidant effect of propofol was suppressed by remifentanil in the case of combined use.

Effect of hyperglycaemia and diabetes on acute myocardial ischaemia-reperfusion injury and cardioprotection by ischaemic conditioning protocols

Diabetic patients are at increased risk of developing coronary artery disease and experience worse clinical outcomes following acute myocardial infarction. Novel therapeutic strategies are required to protect the myocardium against the effects of acute ischaemia-reperfusion injury (IRI). These include one or more brief cycles of non-lethal ischaemia and reperfusion prior to the ischaemic event (ischaemic preconditioning [IPC]) or at the onset of reperfusion (ischaemic postconditioning [IPost]) either to the heart or to extracardiac organs (remote ischaemic conditioning [RIC]). Studies suggest that the diabetic heart is resistant to cardioprotective strategies, although clinical evidence is lacking. We overview the available animal models of diabetes, investigating acute myocardial IRI and cardioprotection, experiments investigating the effects of hyperglycaemia on susceptibility to acute myocardial IRI, the response of the diabetic heart to cardioprotective strategies e.g. IPC, IPost and RIC. Finally we highlight the effects of anti-hyperglycaemic agents on susceptibility to acute myocardial IRI and cardioprotection. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.23/issuetoc.

Consumption of Anacardium Occidentale L. (Cashew Nuts) Inhibits Oxidative Stress through Modulation of the Nrf2/HO-1 and NF-kB Pathways

Ischemia/reperfusion injury is a severe disorder associated with a high mortality. Several antioxidant and pharmacological properties of cashew nuts (Anacardium occidentale L.) and its metabolites from different countries have recently been described. It is a medicinal plant with important therapeutic effects. This study aimed to verify the effect of an oral administration of cashew nuts in a rat model of ischemia/reperfusion (I/R). Adult male rats were subjected to intestinal I/R injury by clamping the superior mesenteric artery for 30 min and then allowing animals to 1 h of reperfusion. Rats subjected to I/R of the gut showed a significant increase in different biochemical markers. In particular, we evaluated lipid peroxidation, tissue myeloperoxidase activity, protein carbonyl content, reactive oxygen species generation and decreased antioxidant enzyme activities. Western blot analysis showed the activation of the NRF2 and NF-kB pathways. Increased immunoreactivity to nitrotyrosine, PARP, P-selectin, and ICAM-1 was observed in the ileum of rats subjected to I/R. Administration of cashew nuts (100 mg/kg) significantly reduced the mortality rate, the fall in arterial blood pressure, and oxidative stress and restored the antioxidant enzyme activities by a mechanism involving both NRF2 and NF-kB pathways. Cashew nuts treatments reduced cytokines plasma levels, nitrotyrosine, and PARP expression as well as adhesion molecules expressions. Additionally, cashew nuts decreased the intestinal barrier dysfunction and mucosal damage, the translocation of toxins and bacteria, which leads to systemic inflammation and associated organs injuries in particular of liver and kidney. Our study demonstrates that cashew nuts administration exerts antioxidant and pharmacological protective effects in superior mesenteric artery occlusion–reperfusion shock.

Aggravated intestinal ischemia‑reperfusion injury is associated with activated mitochondrial autophagy in a mouse model of diabetes

Numerous studies have reported that diabetes is associated with an increased susceptibility to cardiac ischemia- reperfusion injury; however, the mechanism underlying the role of diabetes during intestinal ischemia-reperfusion (IIR) has yet to be elucidated. The present study evaluated the intestinal pathological alterations and possible underlying mechanisms in a mouse model of type 1 diabetes mellitus with IIR. The effects of diabetes were investigated by assessing the histopathology, oxidative stress, inflammatory cytokine levels in intestine tissues and blood plasma, and protein expression levels of phosphatase and tensin homolog-induced putative kinase (PINK1), Parkin and the ratio of light chain 3B (LC3B) II/I. The results demonstrated that diabetes increased the Chiu's intestinal injury score, concentration of interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α, and levels of oxidative stress. Furthermore, the alterations were more pronounced in the diabetes with IIR group. The expression levels of PINK1 and Parkin, as well as the ratio of LC3BII/I, were significantly upregulated in the IIR group compared with the Sham group. Diabetes activated PINK1 and Parkin, and increased the expression of LC3BII. Furthermore, transmission electron microscopy revealed that mitochondrial destruction and the number of autophagosomes was increased in the diabetic groups compared with the non-diabetic groups. Collectively, the results of the present study suggest that diabetes increased intestinal vulnerability to IIR by enhancing inflammation and oxidative stress. Furthermore, IIR was associated with overactivation of mitochondrial autophagy; therefore, the increased vulnerability to IIR-induced intestine damage due to diabetes may be associated with PINK1/Parkin-regulated mitochondrial autophagy.

The role of ischemic preconditioning in the expression of apoptosis-related genes in a rat model of intestinal ischemia-reperfusion injury

Purpose:

To analyze the effects of ischemic preconditioning (IPC) in the expression of apoptosis-related genes in rat small intestine subjected to ischemia and reperfusion.

Methods:

Thirty anesthetized rats underwent laparotomy and were drive into five groups: control (CG); ischemia (IG); ischemia and reperfusion (IRG); IPC and ischemia (IG+IPC); IPC and ischemia and reperfusion (I/RG+IPC). Intestinal ischemia was performed by clamping the superior mesenteric artery for 60 minutes, whereas reperfusion lasted for 120 minutes. IPC was carried out by one cycle of 5 minutes of ischemia followed by 10 minutes of reperfusion prior to the prolonged 60-minutes-ischemia and 120-minutes-reperfusion. Thereafter, the rats were euthanized and samples of small intestine were processed for histology and gene expression.

Results:

Histology of myenteric plexus showed a higher presence of neurons presenting pyknotic nuclei and condensed chromatin in the IG and IRG. IG+IPC and I/RG+IPC groups exhibited neurons with preserved volume and nuclei, along with significant up-regulation of the anti-apoptotic protein Bcl2l1 and down-regulation of pro-apoptotic genes. Moreover, Bax/Bcl2 ratio was lower in the groups subjected to IPC, indicating a protective effect of IPC against apoptosis.

Conclusion:

Ischemic preconditioning protect rat small intestine against ischemia/reperfusion injury, reducing morphologic lesions and apoptosis.

Protective effect of CDDO-imidazolide against intestinal ischemia/reperfusion injury in mice

Intestinal ischemia/reperfusion (I/R) is life-threatening and challenging in clinical practice. CDDO-imidazolide (CDDO-Im) is therapeutic in alleviating I/R injury. Nevertheless, there is a lack of investigation on the effects of CDDO-Im on intestinal I/R. Mice were randomly divided into four groups: (a) the sham group, (b) the CDDO-Im group, (c) the I/R group, and (d) the I/R + CDDO-Im group. Intestinal I/R was performed by clamping arteria mesenteric anterior for 45 min, followed by 24 h reperfusion. In addition, Kaplan–Meier method and the log-rank test were used to compare the survival rates among groups by observing for 24 h. Intestinal I/R in model group demonstrated severe injury of the intestinal mucosa, lung, kidney, and liver. The intestinal mucosal damage and intestinal barrier dysfunction were obviously attenuated in CDDO-Im-treated group compared with the model group. Also, preconditioning with CDDO-Im reduced pulmonary, hepatic and renal damage, and decreased oxidative stress (malondialdehyde (MDA), superoxide dismutase (SOD), and NO) and pro-inflammatory responses (tumor necrosis factor (TNF-α), interleukin 1β (IL-1β), and interleukin 6 (IL-6)) following I/R injury. Furthermore, we also observed that these protective properties of CDDO-Im were accomplished by the activation of nuclear factor E2-related factor 2 (Nrf2) signaling pathway and upregulation of its downstream antioxidant genes, including heme oxygenase (HO-1), NQO-1, and glutamate–cysteine ligase regulatory subunit (GCLM). Our data suggest that CDDO-Im exerts a beneficial effect on intestinal I/R-associated mucosal barrier dysfunction and distant organ injuries.

Remote ischemic preconditioning and tacrolimus in the fetal small bowel transplant in mice

PURPOSE:

To evaluate the effect of remote ischemic preconditioning (IPC-R) in the fetal small bowel transplantation model.

METHODS:

Two groups were constituted: The Isogenic transplant (ISO, C57BL/6 mice, n=24) and the allogenic transplant (ALO, BALB/c mice, n=24). In each group, the animals were distributed with and without IPC-R. It was obtained the following subgroups: Tx, IPC-R, Fk, IPC-Fk, in both strains. Intestinal grafts were stained with hematoxylin and eosin and immunohistochemically.

RESULTS:

The graft development evaluation in ISO group showed that IPC-R reduced the development compared with ISO-Tx (5.2±0.4 vs 9.0±0.8) and IPC-R-Fk increased the graft development compared with IPC-R (11.2±0.7 and 10.2±0.8). In ALO group, IPC-Fk increased the development compared with ALO-Tx and ALO with IPC-R (6.0±0.8, 9.0±1.2, 0.0±0.0, 0.5±0.3). The PCNA expression was increased in ISO group treated with Fk and IPC-R compared to other groups (12.2±0.8 vs Tx: 8.8±0.9, IPC-R: 8.0±0.4 and Fk: 9.0±0.6). The graft rejection was lower in groups treated with IPC-R (-18%), Fk (-68%) or both (-61%) compared with ALO-Tx.

CONCLUSION:

Remote ischemic preconditioning showed benefic effect even associate with Tacrolimus on the development and acute rejection of the fetal small bowel graft in the Isogenic and Allogenic transplants.

Evaluation of Pulmonary Reperfusion Injury in Rats Undergoing Mesenteric Ischemia and Reperfusion and Protective Effect of Postconditioning on this Process

INTRODUCTION

Some publications have demonstrated the presence of lung reperfusion injury in mesenteric ischemia and reperfusion (I/R), but under to diverse methods. Postconditioning has been recognized as effective in preventing reperfusion injury in various organs and tissues. However, its effectiveness has not been evaluated in the prevention of lung reperfusion injury after mesenteric ischemia and reperfusion.

OBJECTIVE

To evaluate the presence of pulmonary reperfusion injury and the protective effect of ischemic postconditioning on lung parenchyma in rats submitted to mesenteric ischemia and reperfusion.

METHODS

Thirty Wistar rats were distributed into three groups: group A (10 rats), which was held mesenteric ischemia (30 minutes) and reperfusion (60 minutes); group B (10 rats), ischemia and reperfusion, interspersed by postconditioning with two alternating cycles of reperfusion and reocclusion, for two minutes each; and group C (10 rats), ischemia and reperfusion interleaved by postconditioning with four alternating cycles of reperfusion and reocclusion of 30 seconds each. Finally, it was resected the upper lung lobe for histological analysis.

RESULTS

There were mild lung lesions (grade 1) in all samples. There was no statistical difference between groups 1 and 2 (P>0.05).

CONCLUSION

The mesenteric ischemia and reperfusion in rats for thirty and sixty minutes, respectively, caused mild reperfusion injury in lung. Postconditioning was not able to minimize the remote reperfusion injury and there was no difference comparing two cycles of two minutes with four cycles of 30 seconds.

Experimental diabetes induced by alloxan and streptozotocin: The current state of the art

Diabetes mellitus is a chronic metabolic disorder with a high prevalence worldwide. Animal models of diabetes represent an important tool in diabetes investigation that helps us to avoid unnecessary and ethically challenging studies in human subjects, as well as to obtain a comprehensive scientific viewpoint of this disease. Although there are several methods through which diabetes can be induced, chemical methods of alloxan- and streptozotocin-induced diabetes represent the most important and highly preferable experimental models for this pathological condition. Therefore, the aim of this article was to review the current knowledge related to quoted models of diabetes, including to this point available information about mechanism of action, particular time- and dose-dependent protocols, frequent problems, as well as major limitations linked to laboratory application of alloxan and sterptozotocin in inducing diabetes. Given that diabetes is known to be closely associated with serious health consequences it is of fundamental importance that current animal models for induction of diabetes should be continuously upgraded in order to improve overall prevention, diagnosis and treatment of this pathological condition.

The protective role of montelukast against intestinal ischemia-reperfusion injury in rats

Several drugs are effective in attenuating intestinal ischemia-reperfusion injury (IRI); however little is known about the effect of montelukast. Fifty rats were randomly assigned to 3 groups: model group (operation with clamping), sham group (operation without clamping), and study group (operation with clamping and 0.2, 2 and 20 mg/kg montelukast pretreatment). Intestinal ischemia-reperfusion was performed by occlusion (clamping) of the arteria mesenterica anterior for 45 min, followed by 24 h reperfusion. Intestinal IRI in the model group led to severe damage of the intestinal mucosa, liver and kidney. The Chiu scores of the intestines from the study group (2 and 20 mg/kg) were lower than that of the model group. Intestinal IRI induced a marked increase in CysLTR1, Caspase-8 and -9 expression in intestine, liver and kidney, which were markedly reduced by preconditioning with 2 mg/kg montelukast. Preconditioning with 2 g/kg montelukast significantly attenuated hepatic tissue injury and kidney damage, and decreased plasma interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels in plasma after intestinal IRI. In conclusion, preconditioning with montelukast could attenuate intestinal IRI and the subsequent systemic inflammatory response in rats.

Near infrared spectroscopy (NIRS) to assess the effects of local ischemic preconditioning in the muscle of healthy volunteers and critically ill patients

Near-infrared spectroscopy (NIRS) permits non-invasive evaluation of tissue oxygen saturation (StO2). A vascular occlusion test (VOT) produces transient controlled ischemia similar to that used in ischemic preconditioning. We hypothesized that we could evaluate local responses to ischemic preconditioning by performing repeated VOTs and observing the changes in different NIRS VOT-derived variables. In healthy volunteers (n=20), four VOTs were performed at 30-min intervals on one day and, in a second group (n=21), two VOTs with time intervals of 5, 15 or 30min were performed on 3 separate days. Two cohorts of patients, one with circulatory shock (n=23) and a hemodynamically stable group (n=20), were also studied, repeating the VOT twice with a 5-min interval. In the 1-day volunteers, there was a median decrease of 15 (6-21)% in the Desc slope (StO2 decrease during VOT) after the second VOT, but no significant change in the Asc slope (StO2 increase after VOT). In the 3-day volunteers, the Desc slope also decreased, regardless of the time interval between VOTs. There was no overall decrease in the Desc slope in either patient cohort with repeated VOTs but there was marked individual patient variability. Patients in whom the Desc slope decreased had less organ dysfunction at admission, required less norepinephrine (0.00 vs 0.08mcg/kg/min, p=0.02), less frequently had sepsis (12 vs 50%, p=0.02) and had a lower mortality (6 vs 39%, p=0.03) compared to those in whom it did not decrease. Repeated NIRS VOT can non-invasively assess the local effects of ischemic preconditioning in the muscle.

Role of cysteinyl leukotriene receptor 1 in intestinal ischemia-reperfusion injury

AIM: To explore the role of cysteinyl leukotriene receptor 1 (CysLTsR1) in intestinal ischemia-reperfusion (I/R) injury.

METHODS: Forty rats were divided into 5 groups: a control group, a model group and low-, medium- and high-dose montelukast groups. After treatment, the water content of the small bowel was determined, and the histological changes in the intestinal tissues were assessed by HE staining. Immunohistochemical assessment of the expression of CysLTR1 and 5-lipoxygenase (5-LOX) was also performed.

RESULTS: Intestinal I/R, small bowel water content (model group 78.13 g ± 1.35 g vs normal group 78.13 g ± 1.35 g, P < 0.05), and CysLTR1 protein and mRNA expression significantly increased in the model group compared with the control group. Application of montelukast decreased intestinal water content (low-, medium-, and high-dose groups 76.47 g ± 1.48 g, 72.67 g ± 5.35 g and 75.39 g ± 3.66 g vs model group 78.13 g ± 1.35 g, P < 0.05), relieved the intestinal tissue injury, and reduced CysLTR1 protein and mRNA expression in intestinal tissues (P < 0.05).

CONCLUSION: CysLTR1 participates in the pathogenesis of intestinal ischemia-reperfusion injury, and may be a target for treatment of I/R injury.