Intestinal Ischemia-reperfusion Group Research Articles

Sacubitril/valsartan protective effect on induced intestinal ischemia/reperfusion injury via immune modulation of IL6/STAT1 pathway.

Intestinal ischemia reperfusion (IIR) is a critical emergency situation that needs immediate intervention. Small intestine is one of the most sensitive tissues to IR injury and it remains a highly morbid condition, with reported mortality rates ranging from 30% to 90%. Thus, we aimed to evaluate the suspected protective role of sacubitril/valsartan (SAC/VAL) on IIR injury. Thirty-two adult male Wistar rats were used in our model and divided into four groups: sham group, SAC/VAL treated group without IIR, IIR group, and SAC/VAL treated group with IIR. SAC/VAL in a dose of 30mg/kg was administered orally just before induction of IIR. SAC/VAL significantly ameliorated IIR-induced changes as it decreased malondialdehyde (MDA), tumor necrosis factor alpha (TNFα), angiotensin II (ANG II), interleukin 6 (IL 6), active caspase 3, and signal transducer- and activator-of transcription (STAT1). However, SAC/VAL administration significantly increased antioxidant parameters such as total antioxidant capacity (TAC), superoxide dismutase (SOD), and reduced glutathione (GSH). Moreover, alteration of the histological structure was observed in IIR group that was improved by SAC/VAL. SAC/VAL prevents IIR-induced damage via modulation of renin angiotensin aldosterone system, antioxidant, anti-apoptotic, anti-inflammatory properties, and regulation of IL6/STAT1 pathway.

Effect of Gallic Acid on Distant Organ Stomach in Intestinal Ischemia Reperfusion Injury

Aim: To examine the effects of gallic acid (GA) in the stomach in rats undergoing intestinal ischemia/reperfusion (IR) with Beclin -1 immunostaining.
 Material-Metod: 24 male Wistar albino rats were divided into control, IR and IR+GA groups. For the IR protocol, 60 minutes of ischemia and reperfusion were applied. The small intestines of the rats in the control group were removed by laparotomy and the abdomen was closed without applying anything else. Ischemia and reperfusion was applied to the superior mesenteric artery (SMA) for 60 minutes with a clamp in rats in the IR group. The blood flow was stopped with a clamp on the SMA of the rats in the IR+GA group and ischemia was applied for 60 minutes. 50 mg/kg gallic acid was given intraperitoneally to the animals, 60 minutes of reperfusion was performed, and the abdomen was closed. The stomach tissues were placed in paraffin blocks after routine histological follow-ups. Five micrometer-thick sections were taken from the paraffin blocks and stained with Hematoxylin-eosin and Beclin-1 immunostaining.
 Results: In the IR group, degeneration of gastric folds, apoptosis of epithelial cells and degeneration of lamina muscularis were observed. In the IR + GA group, gastric folds improved, but cell infiltration in the lamina propria and degeneration in the muscular layer were observed. Beclin-1 expression was positively observed in the surface epithelial cells and gastric glands in the control group. In the IR group, it was observed that the gastric folds were positive on the surface cells and negative in the submucosa, while in the IR + GA group, it was intensely expressed in the gastric epithelium and gastric glands.
 Conclusion: By increasing the expression of beclin-1, GA treatment induced autophagy in gastric mucosal cells, triggered the destruction of damaged cells and provided restoration of the mucosal layer.
 Keywords: Beclin-1, gallic acid, apoptosis

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.

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.

Transplanted hair follicle mesenchymal stem cells alleviated small intestinal ischemia–reperfusion injury via intrinsic and paracrine mechanisms in a rat model

Background: Small intestinal ischemia-reperfusion (IR) injury is a common intestinal disease with high morbidity and mortality. Mesenchymal stem cells (MSCs) have been increasingly used in various intestinal diseases. This study aimed to evaluate the therapeutic effect of hair follicle MSCs (HFMSCs) on small intestinal IR injury. Methods: We divided Sprague–Dawley rats into three groups: the sham group, IR group and IR + HFMSCs group. A small intestinal IR injury rat model was established by clamping of the superior mesenteric artery (SMA) for 30 min and reperfusion for 2 h. HFMSCs were cultured in vitro and injected into the rats through the tail vein. Seven days after treatment, the intrinsic homing and differentiation characteristics of the HFMSCs were observed by immunofluorescence and immunohistochemical staining, and the paracrine mechanism of HFMSCs was assessed by Western blotting and enzyme-linked immunosorbent assay (ELISA). Results: A small intestinal IR injury model was successfully established. HFMSCs could home to damaged sites, express proliferating cell nuclear antigen (PCNA) and intestinal stem cell (ISC) markers, and promote small intestinal ISC marker expression. The expression levels of angiopoietin-1 (ANG1), vascular endothelial growth factor (VEGF) and insulin growth factor-1 (IGF1) in the IR + HFMSCs group were higher than those in the IR group. HFMSCs could prevent IR-induced apoptosis by increasing B-cell lymphoma-2 (Bcl-2) expression and decreasing Bcl-2 homologous antagonist/killer (Bax) expression. Oxidative stress level detection showed that the malondialdehyde (MDA) content was decreased, while the superoxide dismutase (SOD) content was increased in the IR + HFMSCs group compared to the IR group. An elevated diamine oxidase (DAO) level reflected the potential protective effect of HFMSCs on the intestinal mucosal barrier. Conclusion: HFMSCs are beneficial to alleviate small intestinal IR injury through intrinsic homing to the small intestine and by differentiating into ISCs, via a paracrine mechanism to promote angiogenesis, reduce apoptosis, regulate the oxidative stress response, and protect intestinal mucosal function potentially. Therefore, this study suggests that HFMSCs serve as a new option for the treatment of small intestinal IR injury.

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.

The potential protective effect of modafinil in intestinal ischemic reperfusion-induced in rats

ObjectiveIntestinal ischemia reperfusion (IR) is a pathophysiologic process that leads to oxidative stress and acute inflammatory responses. Understanding the mechanisms explaining this inflammation is essential to developing therapeutic strategies. Therefore, the purpose of this study was to evaluate the protective outcome of modafinil (Mod) against intestinal damages caused by intestinal IR injury. Methods/materialsFourty adult Male Wistar rats were randomly divided into four groups: sham control group; intestinal IR group; Mod pre-treated IR group and Mod post-treated IR group. Mod in a dose of 10 mg/kg was injected intraperitoneally once daily for 7 days pre or post IR treatment. ResultsMod significantly attenuated the IR induced elevations in intestinal malondialdehyde (MDA), nitric oxide (NO), tumor necrosis factor alpha (TNF-α), interleukin 1-β (IL-1β) and P-glycoprotein (P-gp) levels, caspase-3 activity. However, a significant increase in TAC was reported as compared with the IR group but its post-treated IR group was highly protective. Mod post-treatment down-regulated the IR induced cyclo-oxygenase-2 (COX-2) over-expression. Distorted mucosa with loss of surface epithelial cells, epithelial separation oedematous lamina propria and inflammatory cellular infiltration detected by histopathological examination of intestinal tissue, were markedly ameliorated by Mod post-treatment.On the other hand, Mod pre-treatment showed less protection against intestinal IR in rats. ConclusionCurrent study suggests that Mod post-treatment ameliorated intestinal damages, so it can be considered a potential therapeutic agent to protect against the major clinical challenge of intestinal injury resulting from IR.

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.

Protective effect of GYY4137, a water‑soluble hydrogen sulfide‑releasing molecule, on intestinal ischemia‑reperfusion.

The present study aimed to clarify the protective effects of p‑methoxyphenyl morpholino‑phosphinodithioic acid (GYY4137), a water‑soluble hydrogen sulfide‑releasing molecule, on a rat model of intestinal ischemia‑reperfusion (IIR). A total of 40 healthy male Sprague Dawley (SD) rats were randomly divided into four groups (n=10/group): Group A, a sham‑surgery group; Group B, the IIR group; group C, rats with IIR that were administered an abdominal injection of low‑dose GYY4137 (40mg/kg); and group D, rats with IIR that were administered high‑dose GYY4137 (80mg/kg). Intestinal histomorphology was observed using hematoxylin and eosin staining, and the concentrations of malondialdehyde (MDA) and superoxide dismutase (SOD) were measured. Apoptotic index (AI) was determined by terminal deoxynucleotidyl‑transferase‑mediated dUTP nick end labeling. Reverse transcription‑quantitative PCR analysis was performed to assess the expression levels of intestinal caspase‑3, Bax and Bcl‑2. Notably, disordered arrangement of intestinal villi and mucosal necrosis were detected in group B, which was substantially improved by GYY4137 treatment (groups C and D). MDA content (nmol/mg) was 2.83±0.36, 9.23±0.78, 4.97±0.45 and 3.51±1.05nmol/mg in groups A, B, C and D, respectively. In addition, SOD concentration (U/mg) was 135.37±3.34, 76.45±1.39, 95.13±1.64 and 115.13±2.54 in groups A, B, C and D, respectively. Furthermore, AI in group B (21.73±1.17%) was markedly higher than that in group A (4.53±0.28%) and in the GYY4137 intervention groups (9.53±0.96 and 6.53±0.76% in groups C and D, respectively). Compared with in group A, the mRNA expression levels of Bax and caspase‑3 were markedly higher in group B (P<0.05), whereas the expression of Bcl‑2 was significantly lower (P<0.05). Furthermore, compared with in group B, Bcl‑2 expression was higher, and Bax and caspase‑3 expression was lower in groups C and D (P<0.05). In conclusion, GYY4137 may alleviate IIR‑induced damage in SD rats.

The protective effects of urapidil on lung tissue after intestinal ischemia-reperfusion injury

Abstract Objective The effects of urapidil in intestinal ischemia-reperfusion (IR) model were investigated using histopathological and biochemical methods. Materials and methods Forty Wistar albino rats were subjected to sham operation (Group 1), IR (Group 2), IR+dimethyl sulfoxide (Group 3), IR+urapidil 0.5 mg/kg (Group 4), and IR+urapidil 5 mg/kg (Group 5). Levels of MDA, TAS, TOS, SOD, MPO, NF-κB, caspase-3, and LC3B were measured. Results and discussion The groups 2 and 3 had significantly higher TOS and MPO levels than the sham group had (p &lt; 0.001), whereas the TAS and SOD levels were significantly lower in Group 2 than in the sham group. In treatment groups, TAS and SOD levels increased, whereas TOS, MPO, and MDA levels decreased compared to Group 2. Caspase-3 and LC3B immunopositivities were seen at severe levels in Group 2 and 3. However, Group 4 and 5 were found to have lower levels of immunopositivity. Immunopositivity was observed in interstitial areas, peribronchial region, and bronchial epithelial cells. A moderate level of NF-κB immunopositivity was seen in Group 2 and 3. Conclusion Our results show that urapidil is one of the antioxidant agents and protects lung tissue from oxidant effects of intestinal IR injury.

Resveratrol Suppresses Gut-Derived NLRP3 Inflammasome Partly through Stabilizing Mast Cells in a Rat Model.

Background Inflammatory responses induced by intestinal ischemia-reperfusion (IIR) lead to serious systemic organ dysfunction and pose a challenge for current treatment. This study aimed at investigating the effects of resveratrol on IIR-induced intestinal injury and its influence on mast cells (MCs) in rats. Methods Rats subjected to intestinal ischemia for 60 min and 4 h of IIR were investigated. Animals were randomly divided into five groups (n = 8 per group): sham, IIR, resveratrol (RESV, 15 mg/kg/day for 5 days before operation) + IIR, cromolyn sodium (CS, MC membrane stabilizer) + IIR, and RESV + compound 48/80 (CP, MC agonist) + IIR. Results Intestinal injury and increased proinflammatory cytokines including tumor necrosis factor-α, interleukin-1β, and interleukin-18 were observed in the IIR group. Intestinal MC-related tryptase and β-hexosaminidase levels were also increased after rats were subjected to IIR accompanied by activation of NLRP3 inflammasomes. Interestingly, pretreatment with resveratrol significantly suppressed the activities of proinflammatory cytokines and attenuated intestinal injury. Resveratrol also reduced MC and NLRP3 inflammasome activation, which was consistent with the effects of cromolyn sodium. However, the protective effects of resveratrol were reversed by the MC agonist compound 48/80. Conclusions In summary, these findings reveal that resveratrol suppressed IIR injury by stabilizing MCs, preventing them from degranulation, accompanied with intestinal mucosa NLRP3 inflammasome inhibition and intestinal epithelial cell apoptosis reduction.

MicroRNA-21 is upregulated during intestinal barrier dysfunction induced by ischemia reperfusion

This study aimed to investigate the expression of miRNA-21 during intestinal barrier dysfunction induced by intestinal ischemia reperfusion. Forty SPF SD rats were divided into 5 groups randomly. Intestinal ischemia-reperfusion injury (IRI) was induced by mesenteric artery occlusion for 1 h and reperfusion for 1 h, and the rats were sacrificed at 1, 3, 6 and 12 h after reperfusion. Fresh intestine tissues were immediately isolated for the measurement of transepithelial electrical resistance (TER). The levels of cytokines, ICAM-1, DAO, iFABP and MPO in serum were determined by ELISA. Intestinal tight junction proteins occludin and claudin-1 were detected by immunofluorescence analysis and Western blot analysis. miR-21 expression in intestinal tissues was measured by RT-PCR. Compared with sham group, the levels of pro-inflammatory cytokines TNF-α and IL-6 and ICAM-1, DAO, iFABP and MPO increased while IL-10 level decreased in intestinal ischemia-reperfusion group. In addition, the levels of intestinal tight junction proteins occludin and claudin-1 decreased while miR-21 level increased in intestinal ischemia-reperfusion group, compared with sham group. In conclusion, miR-21 expression is upregulated during intestinal barrier dysfunction induced by IRI. miR-21 may play an important role in the regulation of intestinal barrier function.

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 ambroxol on experimentally induced acute oxidative stress in the heart, kidney, and intestine in rats

Background Intestinal ischemia–reperfusion (IR) is a frequently occurring phenomenon during abdominal and thoracic vascular surgery, small bowel transplantation, hemorrhagic shock, and surgery using cardiopulmonary bypass, carrying high morbidity and mortality. Ambroxol hydrochloride is an active N-desmethyl metabolite of bromhexine hydrochloride. Ambroxol is indicated as ‘secretolytic therapy in bronchopulmonary diseases associated with abnormal mucus secretion and impaired mucus transport’. Aim The present study was designed to evaluate the effect of ambroxol on experimentally induced acute organ oxidative stress in the form of remote organ injury including kidney and heart after intestinal IR. Materials and methods Thirty animals were classified into five groups. First group: normal control group, second group: nontreated intestinal IR group (intestinal IR was induced by mesenteric artery ligation), third group: ambroxol pretreated intestinal IR group (35 mg/kg), fourth group: ambroxol pretreated intestinal IR group (70 mg/kg), fifth group: ambroxol pretreated intestinal IR group (140 mg/kg). Results Ambroxol significantly reduced the malondialdehyde level in the heart and the kidney when compared with intestinal IR with no medication group. It also improved cardiac troponin and, kidney functions (urea and creatinine) and histopathological affection when compared with intestinal IR with no medication group. Conclusively, in this study ambroxol could have a protective effect against intestinal IR through its antioxidative and anti-inflammatory effect.

Computed Tomography Perfusion Imaging Detection of Microcirculatory Dysfunction in Small Intestinal Ischemia-Reperfusion Injury in a Porcine Model.

ObjectiveTo evaluate multi-slice computed tomography (CT) perfusion imaging (CTPI) for identifying microcirculatory dysfunction in small intestinal ischemia−reperfusion (IR) injury in a porcine model.Materials and MethodsFifty-two pigs were randomly divided into 4 groups: (1) the IR group (n = 24), where intestinal ischemia was induced by separating and clamping the superior mesenteric artery (SMA) for 2 h, followed by reperfusion for 1, 2, 3, and 4 h (IR-1h, IR-2h, IR-3h, and IR-4h; n = 6, respectively); (2) the sham-operated (SO) group (n = 20), where the SMA was separated without clamping and controlled at postoperative 3, 4, 5, and 6 h (SO-3h, SO-4h, SO-5h, and SO-6h; n = 5, respectively); (3) the ischemia group (n = 4), where the SMA was separated and clamped for 2 h, without reperfusion, and (4) baseline group (n = 4), an additional group that was not manipulated. Small intestinal CTPI was performed at corresponding time points and perfusion parameters were obtained. The distal ileum was resected to measure the concentrations of malondialdehyde (MDA) and superoxide dismutase (SOD) and for histopathological examination.ResultsThe perfusion parameters of the IR groups showed significant differences compared with the corresponding SO groups and the baseline group (before ischemia). The blood flow (BF), blood volume (BV), and permeability surface (PS) among the 4 IR groups were significantly different. BF and BV were significantly negatively correlated with MDA, and significantly positively correlated with SOD in the IR groups. Histopathologically, the effects of the 2-h ischemic loops were not significantly exacerbated by reperfusion.ConclusionCTPI can be a valuable tool for detecting microcirculatory dysfunction and for dynamic monitoring of small intestinal IR injury.

Effect of Intestinal Ischemia-reperfusion Injury on the Expression of Chemerin in Mice

To investigate the effect of intestinal ischemia-reperfusion on the protein expression of chemerin in C57BL/6J mice. A total of 16 mice (C57BL/6J, specific pathogen free level) were randomly assigned into two groups (n=8 each): the intestinal ischemia-reperfusion group and the sham group. The intestinal ischemia-reperfusion state was achieved by blocking the super-mesenteric artery. After 60 minutes of ischemia followed by 60 minutes of reperfusion,we determined the protein level of chemerin in various organs and tissues by enzyme-linked immunosorbent assay and Western blot. The sham group underwent the same operation process except for the blocking of the super-mesenteric artery. The protein level of chemerin was significantly elevated in distinctive organs and tissues in the state of intestinal ischemia-reperfusion (P<0.05). The intestinal ischemia-reperfusion can remarkably increase the protein expression of chemerin in some organs and tissues.

Protective effect of intestinal ischemic preconditioning on ischemia reperfusion-caused lung injury in rats.

Intestinal ischemia reperfusion (IR) causes injury of distant critical organs. Remote intestinal ischemic preconditioning (IP) may confer the cytoprotection in critical organs including lung. The authors hypothesized that intestinal IP would be a prophylactic factor in the prevention of distant lung injury induced by IR. Rats were randomly divided into IR, IP, and Sham (S) group. Compared with IR group in the serum and lung tissue, MPO, MDA, TNF-α, and IL-1 levels were significantly decreased in the IP group. Following the same pattern, NO level in the serum and lung tissue was significantly increased in the IP group. And intestinal IP markedly abolished lung injury scores in contrast to IR group. Moreover, intestinal IP significantly attenuated caspase-3 expression, leading to the low expression of Bax and the high expression of Bcl-2. The present study showed that intestinal IP ameliorates the capacity of anti-oxygen free radical, inhibits the release of pro-inflammatory cytokines and alleviates apoptosis in IR-induced lung injury in rats. Intestinal IP may provide a novel prophylactic strategy for treatment of IR-induced lung injury.

Effects of anti-histamine treatment on liver injury triggered by small intestinal ischemia reperfusion in rats.

Mast cell (MC) degranulation has been implicated in small intestinal ischemia reperfusion (IIR) injury, therein, inhibiting overproduction of histamine released from activated MC may provide promising strategies against IIR-mediated liver injuries. The aim of the present study was to explore whether anti-histamine treatment contribute to attenuating IIR-mediated liver injury. Adult SD rats were randomized into sham-operated group (S group), sole IIR group (IIR group), and IIR treated with Ketotifen, a histamine antagonist (IIR+K group), Cromolyn Sodium, a MC stabilizer (IIR+C group), and Compound 48/80, a MC degranulator (IIR+CP group), respectively. IIR was induced by superior mesenteric artery occlusion for 75 min followed by 4 h of reperfusion. The agents were intravenously administrated 5 min before reperfusion to induce different levels of histamine. Subsequently, serum concentrations of ALT, AST and histamine; levels of LDH,TNF-α, IL-8 and MDA as well as SOD activities in the liver were assessed. Histopathologic changes were also evaluated. IIR resulted in severe liver injury as demonstrated by significant increases in injury scores, with concomitant significant increases in serum ALT, AST and histamine levels, as well as LDH, TNF-α, IL-8, and MDA levels in the liver, accompanied by reduction in SOD activities (all P < 0.05, IIR vs. S). Treatments by Ketotifen and Cromolyn Sodium similarly markedly alleviated IIR-mediated liver injury as confirmed by significant reduction of the above biomedical changes whereas Compound 48/80 further aggravated IIR-mediated liver injury by dramatically enhancing the above biomedical changes. Data of our study suggest that anti-histamine treatments may provide promising benefits in alleviating liver injury triggered by IIR.

Somatostatin inhibits the production of interferon-γ by intestinal epithelial cells during intestinal ischemia-reperfusion in macaques.

BackgroundOur previous study found that somatostatin (SST) inhibited the intestinal inflammatory injury in a macaque model of intestinal ischemia–reperfusion (IIR); however, the underlying mechanism was unclear.AimsThe present study was aimed to investigate the effects of SST on IFN-γ and the systemic inflammatory response after IIR.MethodsFifteen macaques were randomly divided into controls, IIR and SST+ IIR groups. ELISA was performed to measure IFN-γ in ileum tissues, ileac epithelial cells (IECs) and ileal lymphocytes, as well as the systemic levels of IL-6, IL-1β, TNF-α and IFN-γ in the peripheral circulation and the portal vein. HE staining was performed to evaluate morphological changes in vital organs. Immunohistochemistry was performed to identify the distribution of IFN-γ, CD4, CD8 and CD57 in the ileum.ResultsAfter IIR, IFN-γ level was significantly increased in the IECs. IL-6, IL-1β and TNF-α were significantly increased in both the portal vein and the peripheral circulation; in contrast, IFN-γ level was increased in the portal vein alone. Prophylactic SST reversed the change in IFN-γ in the IECs and portal vein. SST led to an alleviation of the pathological changes in systemic vital organs. The distribution of CD4+, CD57+ and CD8+ cells was not positively correlated with the secretion of IFN-γ.ConclusionIECs are the main source of IFN-γ production after IIR. SST may indirectly lead to mast cell deactivation through the inhibition of IFN-γ production by IECs. Pretreatment with SST may be beneficial for preventing a massive systemic inflammatory response in vital organs after IIR.

Intestinal ischemia-reperfusion of macaques triggers a strong innate immune response.

To investigate inflammatory injury in the intestinal mucosa after intestinal ischemia-reperfusion (IIR) with Toll-like receptor (TLR)-mediated innate immunity. Ten macaques were randomized into control and IIR groups. The distribution and expression level of TLR2, TLR4, MD2, nuclear factor (NF)-κB p65 and interferon (IFN)-γ were measured by immunohistochemical stain and western blotting. The mRNA expression of TLR4, TLR2, MD2, interleukin (IL)-1β and tumor necrosis factor (TNF)-α were measured by reverse transcriptase-polymerase chain reaction. The cytokine levels in blood and intestinal tissues were measured by ELISA. Obvious hemorrhage and erosion of mucosae were seen in the IIR group. Expression of TLR2, TLR4, MD2, NF-κB p65 and IFN-γ was significantly higher in the IIR group than in the control group (0.13 ± 0.04, 0.22 ± 0.04, 0.16 ± 0.06, 0.65 ± 0.12, 0.38 ± 0.10 vs 0.07 ± 0.04, 0.08 ± 0.03, 0.04 ± 0.02, 0.19 ± 0.06, 0.14 ± 0.05, P < 0.05). In addition, the expression of TLR2, TLR4, MD2, IL-1β and TNF-α mRNA in the IIR group were significantly higher than those of control group(1.52 ± 0.15, 1.39 ± 0.06, 1.94 ± 0.12, 1.48 ± 0.15, 0.66 ± 0.08 vs 0.31 ± 0.05, 0.5 ± 0.04, 0.77 ± 0.05, 0.35 ± 0.08, 0.18 ± 0.04, P < 0.05). Furthermore, IL-1β, IL-6 and TNF-α levels in the macaques ileum and plasma were significantly higher than in the control group (plasma: 86.3 ± 15.2, 1129 ± 248.3, 77.8 ± 16.2 vs 29.5 ± 7.3, 19.8 ± 8.2, 5.6 ± 1.7; ileum: 273.4. ± 44.7, 1636 ± 168.0, 205.5 ± 30.7 vs 76.8 ± 20.5, 663.4 ± 186.9, 49.0 ± 9.4; P < 0.05). After IIR, general inflammatory injury in the intestinal mucosa is correlated with a strong innate immune response, mediated by activation of the TLR-NF-κB-cytokine pathway.