Ischemia-reperfusion Injury In Small Intestine Research Articles

Si-based agent alleviated small bowel ischemia–reperfusion injury through antioxidant effects

The progression of small bowel ischemia–reperfusion (IR) injury causes cells in the intestinal tract to undergo necrosis, necessitating surgical resection, which may result in loss of intestinal function. Therefore, developing therapeutic agents that can prevent IR injury at early stages and suppress its progression is imperative. As IR injury may be closely related to oxidative stress, antioxidants can be effective therapeutic agents. Our silicon (Si)-based agent, an antioxidant, generated a large amount of hydrogen in the intestinal tract for a prolonged period after oral administration. As it has been effective for ulcerative colitis, renal failure, and IR injury during skin flap transplantation, it could be effective for small intestinal IR injury. Herein, we investigated the efficacy of an Si-based agent in a mouse model of small intestinal IR injury. The Si-based agent suppressed the apoptosis of small intestinal epithelial cells by reducing the oxidative stress induced by IR injury. In addition, the thickness of the mucosal layer in the small intestine of the Si-based agent-administered group was significantly higher than that in the untreated group, revealing that Si-based agent is effective against small intestinal IR injuries. In the future, Si-based agents may improve the success rate of small intestine transplantation.

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.

Possible effects of clinoptilolite on small intestinal ischemia-reperfusion injury caused by experimental mesenteric artery occlusion

Abstract Objectives Mesenteric ischemia is a surgical emergency caused by poor blood supply to the intestines. In ischemia, the decrease in blood flow to the tissue causes acidosis and cell death through anaerobic metabolism. Clinoptilolite is one of the most abundant natural zeolites, and it is used for its ion exchange and adsorbent properties. Clinoptilolite has been reported to have an immune-enhancing, anti-carcinogenic, and antioxidant effect in-vitro/in-vivo studies. Clinoptilolite’s histological and biochemical effects on ischemic small intestines. Methods The experimental animals were randomly divided into sham, control, and clinoptilolite treatment group. Clinoptilolite was administered intraperitoneally after ischemia/reperfusion. Cardiac blood was stored for biochemical analysis. Total antioxidant levels and total oxidant levels were analyzed from the sera taken from groups. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) expressions in blood samples were determined by RT-qPCR. At the end of the reperfusion, terminal ileum tissues were taken for histological tests. Results The mean TNF-α expression level was 3.89 in the control group and 2.91 in the clinoptilolite treatment group. The mean IL-6 expression levels were 2.32 in the control group and 1.49 in the clinoptilolite treatment group. Conclusions clinoptilolite administration provided healing in the rat ischemia-reperfusion injury model.

Effect of rutin on experimentally induced small intestinal ischemia reperfusion injury in rats: A biochemical and histopathological evaluation

Effect of rutin on experimentally induced small intestinal ischemia reperfusion injury in rats: A biochemical and histopathological evaluation

Autodigestion by migrated trypsin is a major factor in small intestinal ischemia-reperfusion injury

BackgroundThe pathophysiological role of pancreatic digestive hydrolases in intestinal ischemia-reperfusion (I/R) injury is still not clear. Here, we studied whether ischemia-induced injury to the small intestine can be explained by the autodigestion hypothesis. Materials and methodsMesenteric I/R was induced in rats by superior mesenteric artery occlusion (90 min) and reopening (120 min). Thirty minutes before superior mesenteric artery occlusion, aprotinin (14.7 mg/kg), orlistat (5 mg/kg), and their combination or α1-proteinase inhibitor (60 mg/kg) were injected into the lumen of the small intestine. Systemic and vital parameters, intestinal microcirculation, and mucosal barrier function were monitored during the observation phase; markers of small intestinal injury, as well as trypsin-, chymotrypsin-, elastase-, and lipase-like activities in intestinal effluates were assessed at the end. ResultsThe pattern of small intestinal injury correlated inversely with the local alterations in microvascular tissue perfusion and corresponded with the intestinal distribution of trypsin-like activity. Aprotinin almost completely inhibited trypsin-like activity (P < 0.05) and significantly reduced intestinal tissue injury. Combined with orlistat, it also increased the postischemic blood pressure (P < 0.05) but not the intestinal barrier function. Macroscopic as well as the histologic alterations were decreased by α1-proteinase inhibitor, which significantly improved postischemic blood pressure (P < 0.05). ConclusionsThe I/R-induced pattern of small intestinal injury is likely to result from both local differences in tissue ischemia and the digestive activity of migrated pancreatic trypsin. Therefore, administration of aprotinin and orlistat into ischemic small intestines may be a therapeutic option in patients with a poor diagnosis.

Postconditioning: “Toll-erating” mesenteric ischemia-reperfusion injury?

Postconditioning may prove to be a suitable method to decrease ischemia-reperfusion injury of intestine after mesenteric arterial occlusion. Toll-like-receptor-4 is involved in the pathophysiology of organ damage after ischemia-reperfusion; therefore, the aim of our study was to investigate the effect of postconditioning on the mucosal expression of toll-like-receptor-4. Male Wistar rats (n=10/group) underwent 60minutes of superior mesenteric artery occlusion followed by 6hours of reperfusion in 3 groups: sham-operated, ischemia-reperfusion, and a postconditioned group. Postconditioning was performed by 6 alternating cycles of 10seconds of reperfusion/reocclusion. Blood and tissue samples were collected at the end of reperfusion. Intestinal histopathologic changes and immunohistochemical expression of mucosal caspase-3, antioxidant status, and protein levels of high-mobility group box-1 and toll-like-receptor-4 were assessed. Immunofluorescent labeling and confocal microscopic analysis of toll-like-receptor-4 were performed. Mucosal and serum levels of interleukin-6 and tumor necrosis factor-α protein were measured. Histologic alterations in the postconditioned group were associated with decreased caspase-3 positivity, less toll-like-receptor-4 mRNA, and less protein expression of high-mobility group box-1 and toll-like-receptor-4 in the intestinal villi compared with the ischemia-reperfusion group. Furthermore, a significantly improved antioxidant state of the intestinal mucosa and less mucosal and serum protein levels of interleukin-6 and tumor necrosis factor-α were detected in the postconditioned group. Small intestinal ischemia-reperfusion injury in male Wistar rats caused by the occlusion of the superior mesenteric artery was ameliorated by the use of postconditioning, showing a more favorable inflammatory response, which may be attributed to the decreased mucosal expression of toll-like-receptor-4.

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.

Methane attenuates myocardial ischemia injury in rats through anti-oxidative, anti-apoptotic and anti-inflammatory actions

Myocardial infarction (MI) remains the most frequent cardiovascular disease with high mortality. Recently, methane has been shown protective effects on small intestinal ischemia–reperfusion injury. We hypothesized that methane-rich saline (MS) could protect the myocardium again MI via its anti-oxidative, anti-apoptotic and anti-inflammatory effects. In experiment 1, tetrazolium chloride staining and detection of myocardial enzymes and oxidative and inflammatory parameters were performed at 12h after MI to determine the optimal dose at which intraperitoneal MS exerted the best protective effects on MI. In experiment 2, rats were treated with 10ml/kg MS. Myocyte apoptosis was detected 72h after MI, and cardiac function and myocardial remodeling were evaluated 4 weeks after MI. Results showed different dose of MS reduced infarct area, decreased myocardial enzymes, inhibited inflammation and oxidative stress following MI. The optimal dose of MS was 10mg/kg. Moreover, treatment with 10mg/kg MS for 3 days significantly reduced myocyte apoptosis, improved cardiac function and inhibited myocardial remodeling (reduced anterior wall thickness, attenuated myocyte hypertrophy, and decreased myocardial collagen). MS protects the myocardium of MI rats via its anti-oxidative, anti-inflammatory, anti-apoptotic and anti-remodeling activities. Thus, MS provides a novel and promising strategy for the treatment of ischemic heart diseases.

Monitoring dynamic alterations in calcium homeostasis by T1-mapping manganese-enhanced MRI (MEMRI) in the early stage of small intestinal ischemia-reperfusion injury.

Manganese-enhanced MRI studies have proven to be useful in monitoring physiological activities associated with calcium ions (Ca(2+)) due to the paramagnetic property of the manganese ion (Mn(2+)), which makes it an excellent probe of Ca(2+) . In this study, we developed a method in which a Mn(2+)-enhanced T1 -map MRI could enable the monitoring of Ca(2+) influx during the early stages of intestinal ischemia-reperfusion (I/R) injury. The Mn(2+) infusion protocol was optimized by obtaining dose-dependent and time-course wash-out curves using a Mn(2+)-enhanced T1-map MRI of rabbit abdomens following an intravenous infusion of 50 mmol/l MnCl2 (5-10 nmol/g body weight (BW)). In the rabbit model of intestinal I/R injury, T1 values were derived from the T1 maps in the intestinal wall region and revealed a relationship between the dose of the infused MnCl2 and the intestinal wall relaxation time. Significant Mn(2+) clearance was also observed over time in control animals after the infusion of Mn(2+) at a dose of 10 nmol/g BW. This technique was also shown to be sensitive enough to monitor variations in calcium ion homeostasis in vivo after small intestinal I/R injury. The T1 values of the intestinal I/R group were significantly lower (P < 0.05) than that of the control group at 5, 10, and 15 min after Mn(2+) infusion. Our data suggest that MnCl2 has the potential to be an MRI contrast agent that can be effectively used to monitor changes in intracellular Ca(2+) homeostasis during the early stages of intestinal I/R injury.

The role of mitochondrial permeability transition pore in ischemic post-conditioning for counteracting small intestinal ischemia-reperfusion injury in rabbits

Objective To investigate the role of mitochondrial permeability transition pore (mPTP)in ischemic post-conditioning for counteracting small intestinal ischemia-reperfusion(I/ R)injury in rabbits. Methods Forty New Zealand rabbits were randomly divided into sham-operated group(Sham group), I/R group,ischemic post-conditioning group(IPO group), mPTP inhibitor cyclosporine A group(Cs A group), and IPO+ mPTP agonist atraotydin group(IPO+ Atr group).Parts of small intestine tissues were collected from each group of rabbits after intervention for hematoxylin-eosin(HE) staining. Malondialdehyde(MDA) activity in small intestine tissue was measured by the relevant kit.The mitochondria were isolated and mPTP opening was detected by relevant kits.Intestinal mucosal injury was observed by Chiu's grade 6 scoring method.The apoptosis of intestinal epithelial cells was examined by Td T-mediated d UTP nick end labeling(TUNEL) assay. Results As compared with Sham group, mPTP opening in I/R group was significantly increased(3. 53±0. 36 vs. 1. 37±0. 16, P< 0. 05); MDA activity was significantly increased[(0. 98±0. 14) nmol/mg vs. (0. 34±0. 03) nmol/mg, P< 0. 05]; intestinal mucosa score was significantly increased(4. 66± 0. 41 vs.0. 92±0. 58, P< 0. 05); apoptosis index of intestinal cells was significantly increased [(60. 34±6. 02)% vs.(4. 65±1. 68)%, P< 0. 05].As compared with I/R group, mPTP openings in IPO group and Cs A group were significantly decreased(2. 32±0. 23 and 2. 62±0. 18 vs.3. 53± 0. 36, P< 0. 05); MDA activity was significantly decreased[(0. 55±0. 04) and(0. 62±0. 06) nmol/mg vs.(0. 98±0. 14) nmol/mg, P< 0. 05]; intestinal mucosa score was significantly decreased(3. 25±0. 27 and 3. 52±0. 55 vs.4. 66±0. 41, P< 0. 05); apoptosis of intestinal cells was significantly decreased[(28. 33±3. 20)% and(20. 49±4. 10)% vs.(60. 34±6. 02)%, P< 0. 05]. As compared with IPO group, mPTP openings in IPo+ Atr group were significantly increased(2. 32 ±0. 23 vs.1. 05±0. 16, P< 0. 05); MDA activity was significantly increased[(1. 08±0. 18) vs. (0. 55±0. 04) nmol/mg, P< 0. 05]; intestinal mucosa score was significantly increased(4. 57± 0. 32 vs.3. 25±0. 27, P< 0. 05); apoptosis index of intestinal cells was significantly increased [(40. 35±2. 18)% vs.(28. 33±3. 20)%,P< 0. 05]. Conclusion The mechanism of ischemic post-conditioning for counteracting intestinal ischemia-reperfusion injury in rabbits may be associated with the inhibition of mitochondrial permeability transition pore opening. Key words: Mitochondrial permeability transition pore; Ischemic post-conditioning; Intestine ischemia; Reperfusion injury

Propofol Attenuates Small Intestinal Ischemia Reperfusion Injury through Inhibiting NADPH Oxidase Mediated Mast Cell Activation.

Both oxidative stress and mast cell (MC) degranulation participate in the process of small intestinal ischemia reperfusion (IIR) injury, and oxidative stress induces MC degranulation. Propofol, an anesthetic with antioxidant property, can attenuate IIR injury. We postulated that propofol can protect against IIR injury by inhibiting oxidative stress subsequent from NADPH oxidase mediated MC activation. Cultured RBL-2H3 cells were pretreated with antioxidant N-acetylcysteine (NAC) or propofol and subjected to hydrogen peroxide (H2O2) stimulation without or with MC degranulator compound 48/80 (CP). H2O2 significantly increased cells degranulation, which was abolished by NAC or propofol. MC degranulation by CP further aggravated H2O2 induced cell degranulation of small intestinal epithelial cell, IEC-6 cells, stimulated by tryptase. Rats subjected to IIR showed significant increases in cellular injury and elevations of NADPH oxidase subunits p47phox and gp91phox protein expression, increases of the specific lipid peroxidation product 15-F2t-Isoprostane and interleukin-6, and reductions in superoxide dismutase activity with concomitant enhancements in tryptase and β-hexosaminidase. MC degranulation by CP further aggravated IIR injury. And all these changes were attenuated by NAC or propofol pretreatment, which also abrogated CP-mediated exacerbation of IIR injury. It is concluded that pretreatment of propofol confers protection against IIR injury by suppressing NADPH oxidase mediated MC activation.

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.

Pivotal role of mast cell carboxypeptidase A in mediating protection against small intestinal ischemia–reperfusion injury in rats after ischemic preconditioning

Aim of the studyMast cell (MC) degranulation contributes to the protection mediated by ischemic preconditioning (IPC); however, the precise mechanisms underlying this protection remain largely unknown. Mast cell carboxypeptidase A (MC-CPA) is released solely from MCs and plays a critical role in degrading toxins and endothelin 1 (ET-1). The present study sought to explore whether MC-CPA is involved in the process of IPC in a rodent model of small intestinal ischemia reperfusion (IIR) injury. Materials and methodsIIR injuries were induced in Sprague–Dawley rats by clamping the superior mesenteric artery for 60 min followed by reperfusion for 2 h. One cycle of 10 min intestinal ischemia and 10 min of reperfusion was used in the IPC group, and the MC stabilizer cromolyn sodium and MC potato carboxypeptidase inhibitor were administered before the start of IPC. At the end of experiment, intestine tissue was obtained for assays of the MC-CPA3, tumor necrosis factor-α, interleukin-6, and ET-1 contents and myeloperoxidase activities. Intestinal histologic injury scores and MC degranulation were assessed. Apoptosis indices and cleaved caspase- 3 protein expressions were quantified. ResultsIIR resulted in severe injury, as evidenced by significant increases in injury scores and MC-CPA3, tumor necrosis factor-α, interleukin-6, and ET-1 contents that were accompanied with concomitant elevations in cleaved caspase 3 expression, apoptosis indices, and myeloperoxidase activities. IPC induced a significant increase in MC-CPA3, induced MC degranulation, and attenuated IIR injury by downregulating IIR-induced biochemical changes, whereas cromolyn sodium and potato carboxypeptidase inhibitor abolished the IPC-mediated changes. ConclusionsThese data suggest that IPC protected against IIR injury via the MC degranulation-mediated release of MC-CPA.

Treatment of mice with cromolyn sodium after reperfusion, but not prior to ischemia, attenuates small intestinal ischemia-reperfusion injury

Stabilizing mast cells (MCs) can either inhibit or augment inflammation; however, how improved therapeutic benefits against small intestinal ischemia-reperfusion injury (IIRI) can be achieved by stabilizing MCs remains to be elucidated. The present study was designed to evaluate different treatments with cromolyn sodium (CS, an MC stabilizer), which was administrated either prior to ischemia or after reperfusion. Kunming mice were randomized into a sham-operated group (SH), a sole IIR group (M), in which mice were subjected to 30 min superior mesenteric artery occlusion followed by 3 day or 3 h reperfusion, or IIR, treated with CS 15 min prior to ischemia or 15 min after reperfusion in the PreCr and PostCr groups. The survival rate and Chiu's scores were evaluated. The levels of ET-1, histamine, TNF-α and IL-6, and expression of MC protease 7 (MCP7), MC counts and myeloperoxidase (MPO) activity were quantified. IIR resulted in severe injury as demonstrated by significant increases in mortality and injury score. IIR also led to substantial elevations in the levels of ET-1, histamine, TNF-α and IL-6, expression of MCP7, MC counts and MPO activities (P<0.05, M vs. SH groups). All biochemical changes were markedly reduced in the PostCr group (P<0.05, PostCr vs. M groups), whereas pretreatment of IIR mice with CS prior to ischemia exhibited no changes of ET-1 levels, injury score and inflammation (P>0.05, PreCr vs. M groups). In conclusion, administration of CS after reperfusion, but not prior to ischemia, attenuates IIRI by downregulating ET-1 and suppressing sustained MC activation.

Epidermal Growth Factor Promotes Proliferation and Improves Restoration After Intestinal Ischemia–Reperfusion Injury in Rats

Epidermal growth factor (EGF) is an attractive and promising therapeutic application for intestinal disorders. The current study examined its influence on proliferation and restoration after ischemia-reperfusion (I/R) injury in rat small intestine. Six groups were performed: sham operation (Con); ischemia for 30min with subsequent reperfusion for 30min (I/R); I/R injured with 500μg/kg EGF injected 5min before ischemia (Pre-l); I/R injured with 50μg/kg EGF injected 5min before ischemia (Pre-s); I/R injured with 500μg/kg EGF injected 5min after reperfusion (Post-l); and I/R injured with 50μg/kg EGF injected 5min after reperfusion (Post-s). Intestinal histological damage, crypt cell proliferation degree, mucosal permeability, tight junction proteins expression, and levels of inflammation factors were studied for each group. Compared with the I/R group, administration of EGF in the Pre-l, Pre-s, and Post-l groups all presented a significant proliferation effect. The levels of FD4, IL-6, and TNF-α were dramatically decreased in all EGF-treated groups. Histological destruction was improved and TJs recovery was notably accelerated in all EGF-treated groups except the Post-s group. D-lactate concentration was only diminished in the Pre-l group. These results suggest that mucosally applied EGF can promote intestinal proliferation and improve restoration after I/R injury. EGF intraluminal administration is an effective treatment against intestinal I/R injury.

The Mechanism of Sevoflurane Preconditioning-Induced Protections against Small Intestinal Ischemia Reperfusion Injury Is Independent of Mast Cell in Rats

The study aimed to investigate whether sevoflurane preconditioning can protect against small intestinal ischemia reperfusion (IIR) injury and to explore whether mast cell (MC) is involved in the protections provided by sevoflurane preconditioning. Sprague-Dawley rats exposed to sevoflurane or treated with MC stabilizer cromolyn sodium (CS) were subjected to 75-minute superior mesenteric artery occlusion followed by 2-hour reperfusion in the presence or absence of MC degranulator compound 48/80 (CP). Small intestinal ischemia reperfusion resulted in severe intestinal injury as demonstrated by significant elevations in intestinal injury scores and p47phox and gp91phox, ICAM-1 protein expressions and malondialdehyde and IL-6 contents, and MPO activities as well as significant reductions in SOD activities, accompanied with concomitant increases in mast cell degranulation evidenced by significant increases in MC counts, tryptase expression, and β-hexosaminidase concentrations, and those alterations were further upregulated in the presence of CP. Sevoflurane preconditioning dramatically attenuated the previous IIR-induced alterations except MC counts, tryptase, and β-hexosaminidase which were significantly reduced by CS treatment. Furthermore, CP exacerbated IIR injury was abrogated by CS but not by sevoflurane preconditioning. The data collectively indicate that sevoflurane preconditioning confers protections against IIR injury, and MC is not involved in the protective process.

Inhibiting tryptase after ischemia limits small intestinal ischemia-reperfusion injury through protease-activated receptor 2 in rats

Mast cell activation plays a key role in the process of small intestinal ischemia-reperfusion (IIR) injury; however, the precise role of tryptase released from mast cell on IIR injury remains poorly understood. The aim of this study was to determine the protective role against IIR injury by using tryptase inhibitor protamine after ischemia and to explore the underlying mechanism. Adult Sprague-Dawley rats were randomized into sham-operated group (S), sole IIR group (IIR) in which rats were subjected to 75-minute superior mesenteric artery occlusion followed by 4-hour reperfusion, or IIR being respectively treated with mast cell stabilizer cromolyn sodium (CS group), with the mast cell degranulator compound 48/80 (CP group), or with protamine (P group). The previously mentioned agents were, respectively, administered intravenously 5 minutes before reperfusion. The intestine tissue was obtained for histologic assessment and assays for protein expressions of tryptase and mast cell protease 7 and protease-activated receptor 2 (PAR-2). The intestine mast cell number and levels of tumor necrosis factor κ and interleukin 8 were quantified. IIR resulted in intestinal injury evidenced as significant increases in Chiu's scores, accompanied with concomitant increases of mast cell counts and intestinal tryptase and mast cell protease 7 protein expressions. IIR also increased intestinal PAR-2 expressions, tumor necrosis factor κ, and interleukin 8 levels. Cromolyn sodium and protamine significantly reduced the responses to IIR injury while compound 48/80 further aggravated the previously mentioned biochemical changes. Tryptase releasing from mast cell activation participates in IIR injury through PAR-2, and inhibiting tryptase after ischemia provides promising benefits in limiting IIR injury.

Activation of NF-κB pathway in oral buccal mucosa during small intestinal ischemia-reperfusion injury

BackgroundIntestinal ischemia-reperfusion injury induces intestinal mucosal barrier disruption, systemic inflammatory response syndrome, multiorgan failure, and death. The major pathway for the systemic inflammatory responses depends on nuclear factor kappa B (NF-κB). However, direct measuring of NF-κB in injured tissues is not routinely available. Our aim was to determine whether NF-кB pathway in buccal mucosa is activated during intestinal ischemia-reperfusion injury. Materials and methodsMale Sprague-Dawley rats were prepared for the animal experiment. Superior mesenteric artery (SMA) was exposed and clamped for 30 min in the intestinal ischemia-reperfusion (IR) group. SMA was exposed only in control group. Serum, buccal mucosa, and small intestinal mucosa were harvested in 90 min after reperfusion in IR or 120 min after SMA exposure in control group. Serum cytokine levels and tissue NF-κB pathway activities were measured. ResultsSerum TNF-α (5.49 ± 2.72 versus 1.77 ± 1.20 pg/mL, P = 0.002) and interleukin-6 (232.32 ± 29.98 versus 115.92 ± 17.81 pg/mL, P = 0.002) levels were significantly higher in IR than control group. Intestinal mucosal cytoplasmic phosphorylated inhibitor kappa B (IκB)/IκB ratio, nuclear NF-κB expression, and NF-κB DNA-binding activity were significantly higher in IR than control group. Buccal mucosal cytoplasmic phosphorylated IκB/IκB ratio, nuclear NF-κB expression, and NF-κB DNA-binding activity were also higher in IR than control group. ConclusionBuccal mucosal NF-κB pathway was activated by intestinal ischemia-reperfusion injury. The present study suggests that buccal mucosal may be considered as an indicator for the assessment of intestinal ischemia-reperfusion injury.

Effect of intravenous infusion of hyper-oxygenated solution on small intestinal ischemia-reperfusion injury in rabbits

Objective To investigate the effect of intravenous infusion of hyper-oxygenated solution (HOS) on small intestinal ischemia-reperfusion (I/R) injury in rabbits.Methods Twenty-four rabbits of both sexes,weighing 2.5-3.2 kg,were randomly divided into 3 groups ( n =8 each):sham operation group (group S),I/R group,and HOS group.Small intestinal I/R was produced by clamping the superior mesenteric artery (SMA) for 1 h followed by 2 h of reperfusion in I/R and HOS groups,while the SMA was only clamped in group S.HOS was infused intravenously at a rate of 20 ml· kg-1 ·h -1 via the auricular vein starting from the time immediately after clamping the SMA in group HOS and the equal volume of normal saline was infused instead of HOS in group I/R.Blood samples were obtained from the inferior vena cava at 2 h of reperfusion to detect the concentration of serum lactic acid.The animals were then sacrificed and the small intestine was removed for determination of the malondialdehyde (MDA) content,and activities of superoxide dismutase (SOD),catalase (CAT) and glutathione peroxidase (GSH-Px) in intestinal tissues and for microscopic examination.The pathological changes of the intestinal epithelia were observed and the damage.to the mucous membrane was scored.The internal organs were removed and bacterial translocation from gut to the internal organs was observed.Results Compared with group S,the level of MDA and lactic acid,and rate of bacterial translocation were significantly increased,and the activities of SOD,CAT and GSH-Px were significantly decreased in groups I/R and HOS ( P ＜ 0.05).Compared with group I/R,the level of MDA and lactic acid,rate of bacterial translocation,and activities of SOD,CAT and GSH-Px were significantly decreased in group HOS ( P ＜ 0.05).Conclusion Intravenous infusion of HOS can reduce small intestinal I/R injury in rabbits. Key words: Oxygen; Infusions,intravenous; Reperfusion injury; Intestine, small

The role of HMGB1 in ischemia-reperfusion injury in the rat small intestine

DOI of original article: 10.1016/j.jss.2012.0 * Corresponding author. Uniformed Services MD 20814, USA. Tel.: þ1 301 295 2552; fax: þ E-mail address: hassan_tetteh@hks09.ha 0022-4804/$ e see front matter a 2013 Elsev doi:10.1016/j.jss.2012.04.004 Kojima et al. highlight the High Mobility Group Box Chromosomal Protein 1 (HMGB1) and its potential role in response to ischemia-reperfusion injury in the small intestine [1]. Their results suggest that HMGB1 is an importantmediator in the rat model of ischemia-reperfusion injury, and that therapeutic agents may be developed for targeted therapy in ischemiarelated injury to the small intestine. Several studies have previously explored the impact and role ofHMGB1 inacute lung injuryand ischemia-reperfusion injuryof the kidney, heart, brain, and liver [2e5]. This current studyby the authors appears to be the first report that investigates HMGB1 in the intestinal rat model of ischemia-reperfusion injury, and it offers three unique perspectives that may create opportunity for further investigation and innovation in the treatment of ischemia-reperfusion injury. First, the study demonstrated that increased serum HMGB1 concentration and its localization in damaged intestinal tissue were identified after reperfusion injury. Second, the study suggests that there is strong expression of HMGB1 in the damaged cells of terminal protein of the villi of small intestine. Finally, the administration of anti-HMGB1 antibody appears to ameliorate local disturbances and improve survival in the study subjects over controls. The authors’