Intestinal Ischemia-reperfusion Model Research Articles

MCU inhibition protects against intestinal ischemia‒reperfusion by inhibiting Drp1-dependent mitochondrial fission

Intestinal ischemia‒reperfusion (IIR) injury is a common complication of surgery, but clear molecular insights and valuable therapeutic targets are lacking. Mitochondrial calcium overload is an early sign of various diseases and is considered a vital factor in ischemia‒reperfusion injury. The mitochondrial calcium uniporter (MCU), which is located on the inner mitochondrial membrane, is the primary mediator of calcium ion entry into the mitochondria. However, the specific mechanism of MCU in IIR injury remains to be clarified. In this study, we generated an IIR model using C57BL/6 mice and Caco-2 cells and found increases in the calcium levels and MCU expression following IIR injury. The specific inhibition of MCU markedly attenuated IIR injury. Moreover, MCU knockdown alleviates mitochondrial dysfunction by reducing oxidative stress and apoptosis. Mechanistically, MCU knockdown substantially reduced the translocation of Drp1 and thus its binding to Fis1 receptors, resulting in decreased mitochondrial fission. Taken together, our findings demonstrated that MCU is a novel upstream regulator of Drp1 in ischemia‒reperfusion and represents a predictive and therapeutic target for IIR.

Prostaglandin E-major urinary metabolites as a new biomarker for acute mesenteric ischemia.

Acute mesenteric ischemia (AMI) is an emergent vascular disease caused by cessation of the blood supply to the small intestine. Despite advances in the diagnosis, intervention, and surgical procedures, AMI remains a life-threatening condition. Prostaglandin E2 major urinary metabolite (PGE-MUM), the urinary metabolite of prostaglandin E2, is known to be stable in urine and has been suggested to be a valuable biomarker for intestinal mucosal inflammation, such as ulcerative colitis. We therefore investigated whether or not PGE-MUM levels reflect the degree of ischemia in an intestinal ischemia-reperfusion model. Male rats were used to establish a superior mesenteric artery occlusion (SMAO) group, in which the superior mesenteric artery was clamped, and a sham group. The clamping times in the SMAO group were either 30 minutes or 60 minutes, and reperfusion times were either 3 hours or 6 hours, after which PGE-MUM values were measured. The histological injury score of the SMAO (30-minute ischemia and 6-hour reperfusion group, 1.8 ± 0.4; 60-minute ischemia and 6-hour reperfusion group, 4.7 ± 0.5) and were significantly greater than that of the sham group (0.4 ± 0.7, p < 0.05). The PGE-MUM levels in the SMAO group (30-minutes ischemia and 6-hour reperfusion group, 483 ± 256; 60-minutes ischemia and 6-hour reperfusion group, 889 ± 402 ng/mL) were significantly higher than in the sham group (30-minute and 6-hour observation group, 51 ± 20; 60-minute and 6-hour observation group, 73 ± 32 ng/mL; p < 0.05). Furthermore, the PGE-MUM value was corrected by the concentration of urinary creatinine (Cr). The PGE-MUM/urinary Cr levels in the SMAO group were also significantly higher than in the sham group ( p < 0.05). We found that intestinal ischemia-reperfusion increased urinary PGE-MUM levels depending on the ischemic time. This suggests the potential utility of PGE-MUM as a noninvasive marker of intestinal ischemia.

Qingchang Mixture Prevents the Intestinal Ischemia-reperfusion Injury through TLR4/NF-kB Pathway.

This study aims to determine the protective effect and molecular responses of the traditional Chinese medicine Qingchang mixture on intestinal ischemia-reperfusion (IR) injury. The rat intestinal IR model was prepared. The intestinal ischemic injury was evaluated by HE staining, biochemical assay and western blot. In addition, a human hypoxia-reoxygenation (HR) in vitro model was prepared using intestinal epithelial cells (IEC-6). The viability and apoptosis of IEC-6 cells were measured by CCK8 and apoptosis detection. TAK242 or PDTC was used as a small molecule inhibitor of TLR4 or NF-κB, respectively. Compared with the IR group, the pretreatment of the Qingchang mixture reduced the morphological damage, oxidative stress, inflammatory response, and barrier function damage of the small intestine tissue. IR significantly increased the expression of TLR4 and NF-κB, while the pretreatment of the Qingchang mixture inhibited the expression of TLR4 and NF-κB. Furthermore, the pretreatment of Qingchang mixture, TAK242, or PDTC effectively improved the viability and hindered apoptosis of the HR-induced IEC-6 cells. Traditional Chinese medicine Qingchang mixture prevents intestinal IR injury through TLR4/NF-kB pathway.

Evaluation of the effects of empagliflozin on acute lung injury in rat intestinal ischemia-reperfusion model.

Empagliflozin is a selective sodium-glucose co-transporter (SGLT2) inhibitor that is approved for the treatment of type 2 diabetes. The beneficial effects of empagliflozin on other organ systems including the heart and kidneys have been proven. The aim of this study is to evaluate the role of empagliflozin on acute lung injury induced by intestinal ischemia-reperfusion (I/R). A total of 27 male Wistar albino rats were divided into three groups: sham, I/R, and I/R + empagliflozin; each group containing nine animals. Sham group rats underwent laparotomy without I/R injury. Rats in the I/R group underwent laparotomy, 1h of after ischemia-reperfusion injury (superior mesenteric artery ligation was followed by 2h of reperfusion). Rats in I/R were given empagliflozin (30mg/kg) by gastric gavage for 7days before the ischemia-reperfusion injury. All animals were killed at the end of reperfusion and lung tissue samples were obtained for immunohistochemical staining and histopathological investigation in all groups. Serum glucose, AST, ALT, creatinine, native thiol, total thiol, and disulfide levels and disulfide-native thiol, disulfide-total thiol, and native thiol-total thiol ratios as well as the IMA levels were analyzed and compared among the groups. While intestinal I/R significantly increases serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatinine levels; did not cause any change in homeostasis parameters and IMA level. Empagliflozin treatment had no significant effect on biochemical parameters. Empagliflozin treatment induced a significant decrease in positive immunostaining for IL-1, IL-6, TNF-alpha, caspase 3, caspase 8, and caspase 9 compared to the I/R group in lung tissue samples. Intestinal I/R caused severe histopathological injury including edema, hemorrhage, increased thickness of the alveolar wall, and infiltration of inflammatory cells into alveolar spaces. Empagliflozin treatment significantly attenuated the severity of intestinal I/R injury. It was concluded that empagliflozin treatment may have beneficial effects in acute lung injury, and, therefore, has the potential for clinical use.

The effect of post-reperfusion levosimendan in an experimental intestinal ischemia–reperfusion model

BackgroundLevosimendan has been reported to have a positive effect on ischemia–reperfusion injury. Herein, we aimed to evaluate the effects of levosimendan applied after reperfusion in an experimental intestinal injury-reperfusion (IR) model.MethodsTwenty-one Wistar-albino male rats were separated into three groups: Sham group (n = 7): solely superior mesenteric artery (SMA) was dissected after laparotomy; intestinal ischemia–reperfusion group (IIR, n = 7): SMA was clamped for 60 min and unclamped for 120 min to cause ischemia–reperfusion; IIR + levosimendan group (IIR + L, n = 7): levosimendan was administered in ischemia–reperfusion model. The mean arterial pressures (MAP) were measured in all groups. MAP measurements were performed at the end of stabilization, at the 15th, 30th, and 60th minute of ischemia; at the 15th, 30th, 60th, and 120th minute of reperfusion; and at the end of levosimendan bolus application and when levosimendan infusion concluded. Reperfusion injury was evaluated with tissue malondialdehyde (MDA) and by Chiu score.ResultsMAP at 15 min, 30 min, and 60 min of reperfusion was lower in IIR and IIR + L groups compared with basal inter-group measurements. Decline in MAP at 30 min after reperfusion was statistically significant in IIR and IIR + L groups when compared with the sham group. There was no significant difference between MDA levels in the groups. Chiu score was significantly lower in the sham group when compared to IIR and IIR + L groups and higher in IIR when compared to the IIR + L group.ConclusionLevosimendan leads to a decrease in intestinal damage although it did not affect lipid peroxidation and MAP when administered after reperfusion in an experimental intestinal IR model.

Somatostatin attenuates intestinal epithelial barrier injury during acute intestinal ischemia–reperfusion through Tollip/Myeloiddifferentiationfactor 88/Nuclear factor kappa-B signaling

ABSTRACT In the process of ischemia–reperfusion injury, intestinal ischemia and inflammation interweave, leading to tissue damage or necrosis. However, oxygen radicals and inflammatory mediators produced after reperfusion cause tissue damage again, resulting in severe intestinal epithelial barrier dysfunction. The aim of this study was to determine the protective effect of somatostatin on intestinal epithelial barrier function during intestinal ischemia–reperfusion injury and explore its mechanism. By establishing a rat intestinal ischemia–reperfusion model, pretreating the rats with somatostatin, and then detecting the histopathological changes, intestinal permeability and expression of tight junction proteins in intestinal tissues, the protective effect of somatostatin on the intestinal epithelial barrier was measured in vivo. The mechanism was determined in interferon γ (IFN-γ)-treated Caco-2 cells in vitro. The results showed that somatostatin could ameliorate ischemia–reperfusion-induced intestinal epithelial barrier dysfunction and protect Caco-2 cells against IFN-γ-induced decreases in tight junction protein expression and increases in monolayer cell permeability. The expression of Tollip was upregulated by somatostatin both in ischemia–reperfusion rats and IFN-γ-treated Caco-2 cells, while the activation of TLR2/MyD88/NF-κB signaling was inhibited by somatostatin. Tollip inhibition reversed the protective effect of somatostatin on the intestinal epithelial barrier. In conclusion, somatostatin could attenuate ischemia–reperfusion-induced intestinal epithelial barrier injury by inhibiting the activation of TLR2/MyD88/NF-κB signaling through upregulation of Tollip.

The role of anakinra in the modulation of intestinal cell apoptosis and inflammatory response during ischemia/reperfusion

Background/aim Even though interleukin-1 receptor antagonist, IL-1Ra, is used in certain inflammatory diseases, its effect on ischemia-reperfusion injury is a current research topic. We aimed to investigate the protective effects of anakinra, an IL-1Ra, on the I/R induced intestinal injury.Materials and methods The rat model of intestinal ischemia-reperfusion was induced. Rats were randomized into 4 groups: (group 1) control group, (group 2) I/R group, (group 3 and 4) treatment groups (50 mg/kg and 100 mg/kg, respectively). Gene expressions of caspase-3, TNF-α, IL-1α, IL-6, and apoptotic cells in tissue samples were evaluated by PCR and TUNEL methods, respectively. Plasma levels of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) were studied by the ELISA method and tissue samples were examined histopathologically as well.Results Anakinra inhibited the expression of IL-1α, IL-6, and TNF-α and decreased the SOD, CAT, and MDA caused by ischemia-reperfusion injury in both treatment groups. Caspase-3 expression and TUNEL-positive cell number in treatment groups were also less. Histopathologically, anakinra better preserved the villous structure of the small intestine at a dose of 100 mg/kg than 50 mg/kg. Conclusion Anakinra decreased the intestinal damage caused by ischemia-reperfusion and a dose of 100 mg/kg was found to be histopathologically more effective.

Pretreatment with Propofol Reduces Pulmonary Injury in a Pig Model of Intestinal Ischemia-Reperfusion via Suppressing the High-Mobility Group Box 1 Protein (HMGB1)/Toll-Like Receptor 4 (TLR4)/Protein Kinase R (PKR) Signaling Pathway.

BackgroundPropofol improves rodent pulmonary injury after intestinal ischemia-reperfusion (IIR). However, its effect and underlying mechanisms in large animals remain unclear. Here, we examined whether pretreatment with propofol could relieve lung injury during IIR in pigs, then investigated the underlying mechanism.Material/MethodsA porcine model of IIR-induced lung injury was built by clamping the super mesenteric artery for 2 h and loosening the clamp for 4 h. Randomized grouping was used, and pigs were assigned to a sham-operated group, an IIR with saline pretreatment group, and an IIR with propofol pretreatment group. Pulmonary histopathologic changes, permeability, and oxygenation were assessed to evaluate the effect of propofol. We assessed levels of methane dicarboxylic aldehyde (MDA), superoxide dismutase (SOD), myeloperoxidase (MPO), high-mobility group box 1 protein (HMGB1), Toll-like receptor 4 (TLR4), and double-stranded RNA activated protein kinase R (PKR) to investigate the underlying mechanism.ResultsIIR caused severe lung damage, including morphological changes, high permeability, airway resistance, low static compliance, hypoxemia, and acidemia. Pulmonary and plasma MDA content and MPO activity increased, whereas SOD activity decreased. The HMGB1/TLR4/PKR signaling pathway was activated following IIR. Pretreatment with propofol markedly attenuated lung injury (such as reducing the lung edema and permeability), increased MDA content and MPO activity, and restored SOD activity induced by IIR, accompanied by inhibiting the effect of the HMGB1/TLR4/PKR signaling pathway.ConclusionsIIR caused acute lung injury in pigs. Pretreatment with propofol alleviated the lung injury, which was related to its suppression of the HMGB1/TLR4/PKR signaling pathway.

Cell death induction (extrinsic versus intrinsic apoptotic pathway) by intestinal ischemia-reperfusion injury in rats is time-depended.

We investigate the mechanism of intestinal cell apoptosis and its relation to the time of reperfusion in a rat model of intestinal ischemia-reperfusion (IR). Rats were divided into 4 groups: Sham-24 and Sham-48 rats underwent laparotomy without an intentional ischemic intervention and were sacrificed 24 or 48h hours later; IR-24 and IR-48 rats underwent occlusion of SMA and portal vein for 20min followed by 24 or 48h of reperfusion, respectively. Park's injury score, cell proliferation and apoptosis were determined at sacrifice. Proliferation and apoptosis-related gene and protein expression were determined using Real-Time PCR, Western Blot and Immunohistochemistry. IR-24 rats demonstrated a strong increase in cell apoptosis along with an elevated Bax and decreased Bcl-2 expression and a decrease in cell proliferation (vs Sham-24). IR-48 group showed an increase in cell proliferation and a decrease in cell apoptosis compared to IR-24 animals. IR-48 rats demonstrated an increase in apoptotic rate that was accompanied by greater TNF-α mRNA, Fas mRNA and FasL mRNA compared to Sham-48 animals. While cell apoptosis in IR-24 rats is regulated mainly by intrinsic apoptotic pathway, 48h followed ischemia extrinsic apoptotic pathway is responsible for pro-apoptotic effects of IR injury.

TNF-α Induces Neutrophil Apoptosis Delay and Promotes Intestinal Ischemia-Reperfusion-Induced Lung Injury through Activating JNK/FoxO3a Pathway.

Background Intestinal ischemia is a common clinical critical illness. Intestinal ischemia-reperfusion (IIR) leads to acute lung injury (ALI), but the causative factors of ALI are unknown. The aim of this study was to reveal the causative factors and mechanisms of IIR-induced lung injury. Methods A mouse model of IIR was developed using C57BL/6 mice, followed by detection of lung injury status and plasma levels of inflammatory factors in sham-operated mice and model mice. Some model mice were treated with a tumor necrosis factor-α (TNF-α) inhibitor lenalidomide (10 mg/kg), followed by observation of lung injury status through hematoxylin and eosin staining and detection of neutrophil infiltration levels through naphthol esterase and Ly6G immunohistochemical staining. Additionally, peripheral blood polymorphonuclear neutrophils (PMNs) were cultured in vitro and then stimulated by TNF-α to mimic in vivo inflammatory stimuli; this TNF-α stimulation was also performed on PMNs after knockdown of FoxO3a or treatment with the c-Jun N-terminal kinase (JNK) inhibitor SP600125. PMN apoptosis after stimulation was detected using flow cytometry. Finally, the role of PMN apoptosis in IIR-induced lung injury was evaluated in vivo by detecting the ALI status in the model mice administered with ABT-199, a Bcl-2 inhibitor. Results IIR led to pulmonary histopathological injury and increased lung water content, which were accompanied by increased plasma levels of inflammatory factors, with the TNF-α plasma level showing the most pronounced increase. Inhibition of TNF-α led to effective reduction of lung tissue injury, especially that of the damaging infiltration of PMNs in the lung. In vitro knockdown of FoxO3a or inhibition of JNK activity could inhibit TNF-α-induced PMN apoptosis. Further in vivo experiments revealed that ABT-199 effectively alleviated lung injury and decreased inflammation levels by promoting PMN apoptosis during IIR-induced lung injury. Conclusion TNF-α activates the JNK/FoxO3a pathway to induce a delay in PMN apoptosis, which promotes IIR-induced lung injury.

Absence of the C5a Receptor C5aR2 Worsens Ischemic Tissue Injury by Increasing C5aR1-Mediated Neutrophil Infiltration.

Neutrophil infiltration to ischemic tissues following reperfusion worsens injury. A key driver of neutrophil recruitment and activation is the complement factor C5a, which signals through two receptors, C5aR1 and C5aR2. In this study, we used a neutrophil-dependent mouse model of intestinal ischemia-reperfusion (IR) injury to investigate the underexplored role of C5aR2 in neutrophil mobilization, recruitment, and disease outcomes. We show that intestinal IR induces rapid neutrophil mobilization along with a concomitant reduction in plasma C5a levels that is driven by both C5aR1 and C5aR2. Intestinal IR in C5aR2-/- mice led to worsened intestinal damage and increased neutrophil infiltration. Inhibition of C5aR1 signaling in C5aR2-/- mice with PMX53 prevented neutrophil accumulation and reduced IR pathology, suggesting a key requirement for enhanced neutrophil C5aR1 activation in the absence of C5aR2 signaling. Interestingly, C5aR2 deficiency also reduced circulating neutrophil numbers after IR, as well as following G-CSF-mediated bone marrow mobilization, which was independent of C5aR1, demonstrating that C5aR2 has unique and distinct functions from C5aR1 in neutrophil egress. Despite enhanced tissue injury in C5aR2-/- IR mice, there were significant reductions in intestinal proinflammatory cytokines, highlighting complicated dual protective/pathogenic roles for C5aR2 in pathophysiology. Collectively, we show that C5aR2 is protective in intestinal IR by inhibiting C5aR1-mediated neutrophil recruitment to the ischemic tissue. This is despite the potentially local pathogenic effects of C5aR2 in increasing intestinal proinflammatory cytokines and enhancing circulating neutrophil numbers in response to mobilizing signals. Our data therefore suggest that this balance between the dual pro- and anti-inflammatory roles of C5aR2 ultimately dictates disease outcomes.

Role of hydrogen sulfide on expression of phosphatidylinositol 3 kinase/protein kinase B signal pathway in rats with intestinal ischemia/reperfusion injury

To explore the effect of hydrogen sulfide (H2S) on expression of phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) signal pathway in rats with intestinal ischemia/reperfusion (IRI) injury. Thirty male Wistar rats were divided into sham operation group (Sham group), IRI group, and H2S precursor sodium hydrosuphide (NaHS) intervention group (IRI+NaHS group) by random number table method, with 10 rats in each group. The animal model of IRI was established by 60 minutes superior mesenteric artery (SMA) blockage with non-invasive vascular clamp and 120 minutes reflow. SMA was dissociated and peritoneum cavity was closed in Sham group. The rats in IRI+NaHS group was received NaHS (100 μmol/kg bolus+1.07 mmol×kg-1×h-1 infusion) 10 minutes prior to the onset of reperfusion, while the rats in IRI group and Sham group were received equal volume of normal sodium. Blood in vena cava was collected. H2S was detected by sensitive sulfide electrode. Rats were sacrificed after blood collection. Histopathology change was observed by hematoxylin-eosin (HE) staining, ileal pathological score was studied by Chiu score. The protein expressions of phosphated Akt (p-Akt), Akt, PI3K, cleaved caspase-9, mammalian target of rapamycin (mTOR) were determined by Western Blot. Compared with the Sham group, there was intestinal mucosa structure disorder edema and shedding villous fracture in the IRI group. Ileal pathological score in IRI group was significantly increased (4.21±0.15 vs. 0.15±0.03, P < 0.01), while plasma H2S in IRI group was significantly decreased (μmol/L: 26.72±3.17 vs. 38.34±5.24, P < 0.01). Ileal p-Akt, PI3K, caspase-9 and mTOR protein in IRI group were significantly increased (p-Akt/GAPDH: 2.67±0.12 vs. 0.24±0.05, PI3K/GAPDH: 1.42±0.07 vs. 0.57±0.08, caspase-9/GAPDH: 4.23±0.61 vs. 0.13±0.02, mTOR/GAPDH: 2.17±0.23 vs. 0.23±0.02, all P < 0.01). Compared with the IRI group, pathological changes of intestinal mucosa in the IRI+NaHS group was improved, ileal pathological score was significantly decreased (1.56±0.02 vs. 4.21±0.15, P < 0.01), plasma H2S was significantly increased (μmol/L: 32.36±2.45 vs. 26.72±3.17, P < 0.01) and ileal p-Akt, PI3K were significantly increased (p-Akt/GAPDH: 5.12±0.08 vs. 2.67±0.12, PI3K/GAPDH: 3.14±0.05 vs. 1.42±0.07, both P < 0.01), while caspase-9, mTOR in IRI+NaHS group were significantly decreased (caspase-9/GAPDH: 2.12±0.24 vs. 4.23±0.61, mTOR/GAPDH: 1.37±0.28 vs. 2.17±0.23, both P < 0.01). H2S attenuates intestinal injury in IRI rats by up-regulating PI3K/Akt signal pathway and down-regulating caspase-9 and mTOR.

Pretreatment with dexmedetomidine alleviates lung injury in a rat model of intestinal ischemia reperfusion

The aim of the present study was to investigate the antioxidant mechanisms of dexmedetomidine against lung injury during intestinal ischemia reperfusion (IIR) in rats. The model of IIR-induced acute lung injury was established by occluding the superior mesenteric artery (SMA) for 1 h and reperfusing for 2 h using Sprague-Dawley rats. Pathological examination was used to assess the extent of the lung injury. Oxidative stress was evaluated by measuring malondialdehyde, myeloperoxidase and superoxide dismutase in the lung and plasma. The proinflammatory cytokines tumor necrosis factor-α and interleukin-6 were determined via an enzyme-linked immunosorbent assay. The mRNA and protein expression of nuclear factor-erythroid 2 related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) were determined using a reverse transcription-quantitative polymerase chain reaction and western blotting. Pretreatment with dexmedetomidine significantly inhibited the oxidative stress response and proinflammatory factor release caused by IIR compared with the normal saline group (MDA and SOD in lung and plasma, P<0.05; MPO, IL-1β and TNF-α in lung and plasma, P<0.05). Dexmedetomidine improved pulmonary pathological changes in IIR rats compared with the normal saline group. Investigations into the molecular mechanism revealed that dexmedetomidine increased the expression levels of Nrf2 and HO-1 via activating α2 adrenergic receptors compared with the normal saline group. The antagonism of α2 adrenergic receptors may reverse the protective effect of dexmedetomidine on lung injury during IIR, including decreasing the expression levels of Nrf2 and HO-1, elevating the oxidative stress response and increasing the proinflammatory factor release. In conclusion, pretreatment with dexmedetomidine demonstrated protective effects against lung injury during IIR via α2 adrenergic receptors. The Nrf2/HO-1 signaling pathway may serve a function in the protective effect of dexmedetomidine.

Exosomes Released by Bone Marrow Mesenchymal Stem Cells Attenuate Lung Injury Induced by Intestinal Ischemia Reperfusion via the TLR4/NF-κB Pathway.

Purpose: Acute lung injury (ALI) is a primary component of multiple organ dysfunction syndromes triggered by intestinal ischemia-reperfusion (IIR) which results in high mortality. Existing treatment options remain unsatisfactory. Mesenchymal stem cells (MSCs) have shown considerable promise as a biological therapy for ALI in preclinical studies. However, there are many limitations to stem cell treatment. This study aimed to investigate whether MSC-derived exosomes, a non-cellular alternative, are able to act in a protective capacity similar to that of MSCs for ALI triggered by IIR in a rat model and to explore the underlying mechanisms.Methods: The IIR model involved occlusion of the superior mesenteric artery of a rat for 75 min then reperfusion for 20 h. Rats then received an intravenous injection of either bone marrow-derived MSCs or MSC-derived exosomes. Pathologic alteration of lung tissue, levels of pro-inflammatory cytokines, apoptotic proteins and TLR4/NF-κB signaling were measured to evaluate the therapeutic effect of treatment with either MSCs or exosomes.Results: Manifestations of acute lung injury after IIR were observed as edema and hemorrhage of alveoli and mesenchyme, and inflammatory cell infiltration. MSCs and MSC-derived exosomes both attenuated IIR-induced lung damage by decreased apoptosis and inflammation accompanied by down-regulation of TLR4 and NF-κB expression.Conclusions: MSC-derived exosomes provide protection similar to that of MSCs against IIR-induced ALI via inhibition of TLR4/NF-κB signaling, suggesting that a potential strategy against IIR-mediated acute lung injury could be therapy with exosomes as a non-cellular alternative to MSC transplantation.

Investigation of the effects of naringin on intestinal ischemia reperfusion model at the ultrastructural and biochemical level

We aimed to evaluate the ultrastructural effect of reversing cellular damage, occurring in rats due to ischemia-reperfusion (I/R) in the intestine, with naringin implementation through biochemical parameters. Rats were divided the sham/control, I/R and the naringin groups (n = 7). For I/R group, 120 min of ischemia and 120 min of reperfusion was applied to the superior mesenteric artery. In the naringin group, after 120 min, 50 mg/kg naringin was implemented, and then 120 min of reperfusion was applied. Morphological evaluation was performed via Chiu score and electron microscopy. The antioxidant parameters were examined. Chiu score in I/R (p < 0.01) and naringin (p < 0.05) groups were higher than the sham/control group. In ultrastructural level some irregularity were observed in I/R group. Although it decreased in the naringin group, the damage was observed to continue. Malondialdehyde (MDA) amount and Superoxide dismutase activity (SOD) in I/R group were higher in comparison to the sham/control group (p < 0.01), while glutathione peroxidase activity (Gpx) was found to be lower (p < 0.01). SOD (p < 0.05) and MDA (p < 0.01) were decreased by naringin group. Gpx was decreased in I/R group compared to sham/control group (p < 0.01) and elevated due to naringin administration (p < 0.05). Catalase activity was observed to decrease in the naringin group compared to control and I/R groups (p < 0.01). It was determined that naringin provided limited healing at the ultrastructural level but also effected recovery within antioxidant parameters.

Cold-inducible RNA-binding protein-derived peptide C23 attenuates inflammation and tissue injury in a murine model of intestinal ischemia-reperfusion

Cold-inducible RNA-binding protein is a novel damage-associated molecular pattern that causes inflammation. C23, a short peptide derived from cold-inducible RNA-binding protein, has been found to have efficacy in blocking cold-inducible RNA-binding protein's activity. We hypothesized that C23 reduces inflammation and tissue injury induced by intestinal ischemia-reperfusion. Male C57BL/6 mice were subjected to 60 minutes of intestinal ischemia by clamping the superior mesenteric artery. Immediately after reperfusion, either normal saline (vehicle) or C23 peptide (8 mg/kg body weight) was injected intraperitoneally. Four hours after reperfusion, blood, intestinal, and lung tissues were collected for analysis of inflammatory and tissue injury parameters. Cold-inducible RNA-binding protein levels in the intestinal tissues were significantly increased following intestinal ischemia-reperfusion. Histologic examination of the intestine revealed a significant reduction in injury score in the C23 group by 48% as compared with the vehicles after intestinal ischemia-reperfusion. The serum levels of lactate dehydrogenase and aspartate aminotransferase were increased in animals that underwent vehicle-treated intestinal ischemia-reperfusion, whereas C23-treated animals exhibited significant reductions by 48% and 53%, respectively. The serum and intestinal tissue levels of tumor necrosis factor α were elevated in vehicle-treated intestinal ischemia-reperfusion mice but decreased by 72% and 69%, respectively, in C23-treated mice. Interleukin-6 mRNA levels in the lungs were reduced by 86% in the C23-treated group in comparison to the vehicle-treated group after intestinal ischemia-reperfusion. Expression of macrophage inflammatory protein 2 and level of myeloperoxidase activity in the lungs were dramatically increased after intestinal ischemia-reperfusion and significantly reduced by 91% and 25%, respectively, in the C23-treated group. C23 has potential to be developed into a possible therapy for reperfusion injury after mesenteric ischemia and reperfusion.

Diazoxide reduces local and remote organ damage in a rat model of intestinal ischemia reperfusion

BackgroundIntestinal ischemia reperfusion is a common clinical condition that causes functional impairment. Once tight junctions are damaged, barrier function is compromised, and the intestines become a source for entry of bacterial and inflammatory mediators into the circulation, leading to systemic inflammatory response syndrome, multiple organ failure, and death. It is possible that diazoxide could protect the intestines against ischemia reperfusion. The aim of this study is to determine whether diazoxide can provide protection in a rat model of intestinal ischemia reperfusion. MethodsA total of 32 adult male specific pathogen-free Wistar rats were randomized into three groups: a control group, n = 6; a saline group, n = 13; and a diazoxide group, n = 13. The saline and diazoxide groups underwent clamping of the superior mesenteric artery for 1 h, with samples in all the groups being collected 12 h later. ResultsIntestinal histology showed greater damage in the intestinal ischemia reperfusion groups. mRNA expression of zonula occludens-1 and occludin (tight junction proteins) and interleukin-6 and cyclooxygenase-2 was the highest in the Saline group. The Diazoxide group showed a reduction in aspartate aminotransferase serum levels compared with the other groups. ConclusionsIncreased expression of zonula occludens-1, occludin, and cyclooxygenase-2 suggested a greater regenerative effort because of more severe lesions in the saline group. In addition, increased expression of interleukin-6 in the saline group was suggestive of inflammation, indicating that diazoxide had protective effects in the diazoxide group. Reduced aspartate aminotransferase in the diazoxide group suggested liver protection. Diazoxide protects the intestines and liver from intestinal ischemia reperfusion lesions in rats.

Effect of atenolol pre-treatment in heart damage in a model of intestinal ischemia-reperfusion.

To investigate the effects of atenolol in inflammatory mediator and oxidative stress in a myocardial injury by intestinal ischemia/reperfusion in rat model. Adult Wistar male rats were randomly (n=8), anesthetized and divided in: Sham: submitted to operation only; group SS+IR: intravenous saline infusion following superior mesenteric artery occlusion during 60 minutes (ischemia) and open for 120 minutes (reperfusion); group AT+IR: intravenous atenolol infusion (2 mg/kg) following superior mesenteric artery occlusion during 60 minutes (ischemia) and open for 120 minutes (reperfusion); and group AT+I+AT+R: intravenous atenolol infusion following superior mesenteric artery occlusion during 60 minutes (ischemia) and in the time 45 minutes other atenolol doses were administrated and the artery was open for 120 minutes (reperfusion), all animals were submitted to muscular relaxation for mechanical ventilation. In the end of experiment the animals were euthanized and the hearts tissue were morphology analyzed by histology and malondialdehyde by ELISA, and the plasma were analyzed for tumor necrosis factor-alpha by ELISA. The group SS+IR demonstrated the higher malondialdehyde levels when compared with the atenolol treated-groups (p=0.001) in the heart tissue. The tumor necrosis factor-alpha level in plasma decrease in the treated groups when compared with SS+IR group (p=0.001). Histology analyses demonstrate pyknosis, edema, cellular vacuolization, presence of inflammatory infiltrate and band contraction in the heart tissue of the rats. Atenolol significantly reduce the degree of cardiac damage after intestinal ischemia-reperfusion.

Protective effects of N-acetylcystein and atorvastatin against renal and hepatic injury in a rat model of intestinal ischemia-reperfusion.

We sought to examine whether the separate and combined effect of N-acetylcystein (NAC) and atorvastatin prevented hepatic and renal tissue injury induced by intestinal ischemia-reperfusion (I/R). 40 male Wistar rats were allocated into 5 experimental groups; Control (n=8): sham, I/R (n=8): rats underwent occlusion of superior mesenteric artery for 45min, Atorvastatin (n=8): rats received 10mg/kg atorvastatin, NAC (n=8): rats received 160mg/kg NAC, NAC&Atorvastatin (n=8): rats received both aforementioned agents. Administration of the agents was facilitated by oral gavage 24h before I/R. Serum levels of urea, creatinine, transaminases, IL-1β, IL-6, TNF-α, ICAM-1, as well as liver and kidney histopathological examination were evaluated. Pretreatment with either NAC or Atorvastatin or their combination led to lower levels of transaminases and ICAM-1 (2.75±0.46, 2.88±0.84 and 1.5±0.76 respectively for NAC, Atorvastatin and I/R groups), while only their combination led to lower ratios of IL-1, IL-6 and TNF-α than I/R group (1.3±0.12 vs 1.94±0.54, 1.21±0.11 vs 2.12±0.96 and 1.33±0.11 vs 2.14±0.77, respectively). NAC was associated with enhanced renal tissue histology, while atorvastatin was found superior in protecting hepatic tissue degenaration. Both agents, seperately and combined, seem to exhibited tissue-specific protective activity against intestinal I/R induced injury.

Use of soluble complement receptor type 1 to prevent local and distant organ injury in a rat intestinal ischemia reperfusion model

Use of soluble complement receptor type 1 to prevent local and distant organ injury in a rat intestinal ischemia reperfusion model