影响脓毒症受损肠黏膜修复的机制

目的 探讨影响脓毒症肠黏膜损害后修复的因素。方法 采用肓肠结扎穿孔(CLP)所致脓毒症模型,分别以CLP后6,24,48 h不同时间段观测肠黏膜损伤程度和修复过程,前者包括形态学观察及细胞凋亡的测定,后者包括肠黏膜修复的杯状细胞变化、黏膜肠三叶因子3(TFF3)、转化生长因子β1(TGF-β1)以及TNF-α、IL-1含量。结果 形态学观察显示肠黏膜呈持续损害状态,6h的损害积分明显小于24h,48 h组(P＜0.05),后两组之间差异无统计学意义(P＞0.05);磷酸化caspase-3蛋白在3组均高于sham组4倍以上;黏膜IL-1,TNF-α含量明显高于sham组3～4倍,其中24h及48 h组明显高于6h组。肠黏膜的修复过程不明显,损伤黏膜未见到明显的杯状细胞积聚;TFF3在6h组轻度增高,24h及48 h组表达下降;杯状细胞数量在CLP的3个组明显减少;TGF-β1在6h组增高,其他两组均接近于sham组。结论 严重脓毒症肠黏膜持续的高炎症状态、杯状细胞功能以及黏膜重建能力下降,影响了受损肠屏障的修复。     

Changes of the immunological barrier of intestinal mucosa in rats with sepsis

BACKGROUND:

Sepsis has become the greatest threat to in-patients, with a mortality of over 25%. The dysfunction of gut barrier, especially the immunological barrier, plays an important role in the development of sepsis. This dysfunction occurs after surgery, but the magnitude of change does not differentiate patients with sepsis from those without sepsis. Increased intestinal permeability before surgery is of no value in predicating sepsis. The present study aimed to observe the changes of intestinal mucosal immunologic barrier in rat models of sepsis induced by cecal ligation and puncture.

METHODS:

Sixty Sprague-Dawley rats were randomly divided into a sepsis group (n=45) and a control group (n=15). The rats in the sepsis group were subjected to cecal ligation and puncture (CLP), whereas the rats in the control group underwent a sham operation. The ileac mucosa and segments were harvested 3, 6 and 12 hours after CLP, and blood samples were collected. Pathological changes, protein levels of defensin-5 (RD-5) and trefoil factor-3 (TFF₃) mRNA, and lymphocytes apoptosis in the intestinal mucosa were determined. In an additional experiment, the gut-origin bacterial DNA in blood was detected.

RESULTS:

The intestinal mucosa showed marked injury with loss of ileal villi, desquamation of epithelium, detachment of lamina propria, hemorrhage and ulceration in the sepsis group. The expression of TFF₃ mRNA and level of RD-5 protein were decreased and the apoptosis of mucosal lymphocyte increased (P<0.05) in the sepsis group compared with the control group. Significant differences were observed in RD-5 and TFF₃ mRNA 3 hours after CLP and they were progressively increased 6 and 12 hours after CLP in the sepsis group compared with the control group (P<0.05, RD-5 F=11.76, TFF₃ F=16.86 and apoptosis F=122.52). In addition, the gut-origin bacterial DNA detected in plasma was positive in the sepsis group.

CONCLUSION:

The immunological function of the intestinal mucosa was impaired in septic rats and further deteriorated in the course of sepsis.KEY WORDS: Sepsis, Mucosal immunology, Defensin-5, Trefoil factor family 3, Cecal ligation and puncture     

Effect of transforming growth factor-β1 on monocyte Toll-like receptor 4 expression in septic rats

BACKGROUND:

Sepsis is a tough problem in critical ill patients. This study aimed to investigate the dynamic changes of monocyte Toll-like receptor (TLR) 4 expression in peripheral blood of septic rats and to determine the effects of transforming growth factor (TGF)-β₁ on TLR4 expression.

METHODS:

Altogether 132 clean level SD rats were randomly divided into a control group (n=12), a sepsis model group (n=60), and a TGF-β₁ intervention group (n=60). In the sepsis model group and TGF-β₁ intervention group, the rats were subdivided into five groups (2-hour group, 6-hour group, 12-hour group, 24-hour group, and 48-hour group), with 12 rats in each group. Cecal ligation puncture (CLP) was performed in the sepsis model group and TGF-β₁ intervention group to establish models of sepsis. The rats in the sepsis model group were injected with 1 mL normal saline at the caudal vein 0.5 hour after the model establishment; the rats in the TGF-β₁ intervention group were injected with 20 ng/mL or 250 g TGF-β₁ 0.5 hour after the model establishment. Flow cytometry was used to detect the change of monocyte TLR4 in peripheral blood, and enzyme-linked immunosorbent assay (ELISA) was used to detect the change of TNF-α level in peripheral blood.

RESULTS:

At 6-12 hours after CLP, the monocyte TLR4 in peripheral blood started to decrease, and reached the lowest level at 12 hours. Compared to the control group, the monocyte TLR4 expression at 6 and 12 hours was lowered significantly (P<0.05). Compared to the sepsis model group at 2, 24 and 48 hours after CLP, the monocyte TLR4 expression in the TGF-β₁ intervention group decreased dramatically (P<0.05), but there were no differences between the two groups at 6 and 12 hours respectively. Compared to the control group, the concentration of NF-κ in liver tissue increased significantly 6 hours after CLP (P<0.05). After use of TGF-β₁, the concentration of NF-κ was decreased significantly but still higher than that of the control group. Compared to the control group, the concentration of TNF-α in peripheral blood was increased significantly at 2-48 hours after CLP (P<0.05). After use of TGF-β₁, TNF-α was further increased.

CONCLUSION:

During sepsis, TGF-β₁ can decrease the monocyte TLR4 expression and NF-κ in liver tissue, but facilitate the formation of proinflammatory mediator TNF-α. This finding indicates that TGF-β₁ may play a role in promoting inflammatory response during sepsis, but this regulation is not via direct regulation of monocyte TLR4 in peripheral blood.KEY WORDS: Sepsis, TGF-β₁, TLR4, Monocyte, TNF-α     

Cardioprotective effect of erythropoietin on sepsis-induced myocardial injury in rats

BACKGROUND:

Sepsis-induced myocardial injury is one of the major predictors of morbidity and mortality of sepsis. The cytoprotective function of erythropoietin (EPO) has been discovered and extensively studied. However, the cardioprotective effects of EPO on sepsis-induced myocardial injury in the rat sepsis model has not been reported.

METHODS:

The rat models of sepsis were produced by cecal ligation and perforation (CLP) surgery. Rats were randomly (random number) assigned to one of three groups (n=8 for each group): sham group, CLP group and EPO group (1000 IU/kg erythropoietin). Arterial blood was withdrawn at 3, 6, 12, and 24 hours after CLP. cTnI, BNP, CK-MB, LDH, AST, TNF-α, IL-6, IL-10, and CRP were tested by the ELISA assay. Changes of hemodynamic parameters were recorded at 3, 6, 12, 24 hours after the surgery. Histological diagnosis was made by hematoxylin and eosin. Flow cytometry was performed to examine cell apoptosis, myocardium mitochondrial inner membrane potential, and NF-κB (p65). Survival rate at 7 days after CLP was recorded.

RESULTS:

In the CLP group, myocardial enzyme index and inflammatory index increased at 3, 6, 12 and 24 hours after CLP compared with the sham group, and EPO significantly blocked the increase. Compared with the CLP group, EPO significantly improved LVSP, LV +dp/dt_max, LV −dp/dt_min, and decreased LVEDP at different time. EPO blocked the reduction of mitochondrial transmembrane potential, suppressed the cardiomyocyte apoptosis, inhibited the activation of NF-κB, and reduced the production of proinflmmatory cytokines. No difference in the survival rate at 7 days was observed between the CLP group and the EPO group.

CONCLUSION:

Exogenous EPO has cardioprotective effects on sepsis-induced myocardial injury.KEY WORDS: Sepsis, Sepsis-induced myocardial injury, Apoptosis, Chondriosome membrane potential, Nuclear factor κB p65, Erythropoietin, Inflammatory cytokines, Rat     

Effect of tumor necrosis factor-α on ventricular arrhythmias in rats with acute myocardial infarction in vivo

BACKGROUND:

Acute myocardial infarction (AMI) is an acute cardiovascular emergency. This study was undertaken to assess the effect of tumor necrosis factor-α (TNF-α) on ventricular arrhythmias induced by AMI in rats in vivo.

METHODS:

Two hundred and forty male Wistar rats were randomized into a sham-operation group, an AMI group, and a recombinant human tumor necrosis factor receptor:Fc fusion protein(rhTNFR:Fc) group. Acute anterior wall myocardial infarction was produced in the AMI group by ligating the left anterior descending coronary artery (LAD), and there was no ligation but operation in the sham-operation group. The rhTNFR:Fc group was treated with rhTNFR:Fc(10 mg/kg), a TNF-α antagonist, 24 hours before LAD ligation. The spontaneous and induced programmed electrical stimulation ventricular arrhythmias were recorded at baseline and 10 minutes, 20 minutes, 30 minutes, 60 minutes, 3 hours, 6 hours and 12 hours after ligation. At the same time the protein and mRNA expression levels of TNF-α among different groups were detected by histochemistry and real-time fluorescent quantitative PCR.

RESULTS:

Expression of TNF-α increased markedly from 10 minutes after infarction, peaked at 20-30 minutes, and returned to baseline gradually in the AMI group and rhTNFR:Fc group. The time-windows of spontaneous and induced ventricular arrhythmias were similar. Compared with the AMI group, the rhTNFR:Fc group showed a lesser expression of TNF-α protein and a lower incidence of ventricular arrhythmias (P<0.05). There was no obvious change in the sham-operation group.

CONCLUSION:

The expression of TNF-α induced by AMI could contribute to the onset of ventricular arrhythmias.KEY WORDS: Acute myocardial infarction, Tumor necrosis factor-α, Ventricular arrhythmia, Recombinant human tumor necrosis factor receptor, Fc fusion protein (rhTNFR: Fc)     

血必净对脓毒症大鼠回肠黏膜形态学的影响

目的 观察不同给药途径及不同给药时间情况下,血必净注射液对脓毒症大鼠回肠黏膜形态学的影响.方法 91只健康Sprague-Dawley大鼠由中山大学实验动物中心提供,随机分为正常对照组(n=7)、脓毒症组(n=21)、灌胃给药+脓毒症组(预处理组)(n=21)、静脉给药+脓毒症组(预处理组)(n=21)和脓毒症+静脉给药组(治疗组)(n=21).除正常对照组外,其余各组按手术后3 h,6 h,12 h再分3组,每组7只.采用盲肠结扎穿孔法制作脓毒症模型.正常对照组不予任何处理,灌胃给药+脓毒症组于术前2 h灌胃给药(5 mL/kg血必净);静脉给药+脓毒症组于术前2 h尾静脉给药(5 mL/kg血必净);脓毒症+静脉给药组于术后2 h尾静脉给药(5 mL/kg血必净).正常对照组不作任何处理,直接留取组织标本;其余各组于术后3 h,6 h,12 h分别活杀大鼠留取回肠标本,用以进行形态学观察及回肠上皮损伤指数测定.用SPSS 13.0统计软件进行统计学分析;组间比较用方差分析,P<0.05为差异具有统计学意义.结果 预处理组及治疗组大鼠回肠上皮损伤程度均较脓毒症组减轻(P<0.01);预处理组中,静脉给药较灌胃给药的保护效果更好(P<0.05).结论 血必净注射液能减轻脓毒症大鼠回肠黏膜的损伤程度,预先静脉给药效果更佳.     

脓毒症大鼠肠黏膜免疫屏障功能的变化

目的 研究脓毒症对大鼠肠黏膜免疫屏障功能的影响.方法 60只SD大鼠随机(随机数字法)分为对照组(n=15)和脓毒症组(n=45),采用盲肠结扎穿孔术(CLP)建立脓毒症模型.模型建立后3 h、6 h和12 h留取回肠黏膜和全血标本.分别进行肠黏膜形态学观察、肠防御素5(RD-5)及肠三叶因子3(TFF_3)Mrna表达水平检测、肠黏膜淋巴细胞凋亡分析,以及外周血中肠源性细菌DNA定性检测.结果 CLP所致脓毒症导致大鼠回肠黏膜明显损害,主要表现为上皮脱落、固有层分离、毛细血管出血和溃疡形成;脓毒症组模型建立后3 h即出现RD-5和TFF_3 Mrna表达显著性减少(与正常组比较,P<0.05),且6 h和12 h组进行下降(与3 h组比较,P<0.05),肠黏膜淋巴细胞凋亡数亦显著增加(P<0.05);同时,脓毒症组全血肠源性细菌DNA扩增全部阳性.结论 脓毒症时大鼠肠黏膜免疫屏障功能显著减退,且随脓毒症的发展而进行性恶化.     

Propofol increases morbidity and mortality in a rat model of sepsis

IntroductionSevere sepsis is associated with approximately 50% mortality and accounts for tremendous healthcare costs. Most patients require ventilatory support and propofol is commonly used to sedate mechanically ventilated patients. Volatile anesthetics have been shown to attenuate inflammation in a variety of different settings. We therefore hypothesized that volatile anesthetic agents may offer beneficial immunomodulatory effects during the course of long-term intra-abdominal sepsis in rats under continuous sedation and ventilation for up to 24 hours.MethodsSham operation or cecal ligation and puncture (CLP) was performed in adult male Wistar rats followed by mechanical ventilation. Animals were sedated for 24 hours with propofol (7 to 20 mg/kg/h), sevoflurane, desflurane or isoflurane (0.7 minimal alveolar concentration each).ResultsSeptic animals sedated with propofol showed a mean survival time of 12 hours, whereas >56% of all animals in the volatile groups survived 24 hours (P <0.001). After 18 hours, base excess in propofol + CLP animals (−20.6 ± 2.0) was lower than in the volatile groups (isoflurane + CLP: -11.7 ± 4.2, sevoflurane + CLP: -11.8 ± 3.5, desflurane + CLP -14.2 ± 3.7; all P <0.03). Plasma endotoxin levels reached 2-fold higher levels in propofol + CLP compared to isoflurane + CLP animals at 12 hours (P <0.001). Also blood levels of inflammatory mediators (tumor necrosis factor-α, interleukin-1β, interleukin-10, CXCL-2, interferon-γ and high mobility group protein-1) were accentuated in propofol + CLP rats compared to the isoflurane + CLP group at the same time point (P <0.04).ConclusionsThis is the first study to assess prolonged effects of sepsis and long-term application of volatile sedatives compared to propofol on survival, cardiovascular, inflammatory and end organ parameters. Results indicate that volatile anesthetics dramatically improved survival and attenuate systemic inflammation as compared to propofol. The main mechanism responsible for adverse propofol effects could be an enhanced plasma endotoxin concentration, leading to profound hypotension, which was unresponsive to fluid resuscitation.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0751-x) contains supplementary material, which is available to authorized users.     

丙酮酸乙酯对脓毒症大鼠肠黏膜屏障功能保护作用的研究

目的 观察丙酮酸乙酯(ethyl pyruvate ,EP)干预治疗对脓毒症大鼠生存率和肠黏膜屏障的影响.方法 ①EP对脓毒症大鼠生存率的影响:无特定病原雄性SD大鼠100只随机分为假手术组(A组)、脓毒症组(B组)、EP早期治疗组(C组)及EP延迟治疗组(D组),每组25只,利用盲肠结扎穿孔法(cecal ligation and puncture,CLP)制作大鼠脓毒症模型,各组均于术后6、12、18、24、36、48、60、72 h腹腔内注射给药3 mL,C、D组分别于术后6、12 h开始予EP(40 mg/kg),A、B两组同法予等量林格乳酸钠溶液(ringer lactate solution ,RLS),每隔12 h记录死亡情况,分析比较5 d生存率;②EP对脓毒症大鼠肠黏膜屏障的影响:80只无特定病原雄性SD大鼠随机分为四组,每组20只,分组及给药方法与方法一相同,术后24、48 h各处死10只.测定各时间点血浆D-乳酸、DAO的变化,同时用透射电镜观察术后48 h肠黏膜上皮细胞超微结构的变化.采用Kaplan- Meier生存分析法进行生存分析,多组均数间比较采用单因素方差分析的方法, 多组均数间两两比较采用SNK-q检验,P＜0.05为差异有统计学意义.结果 A、B、C、D四组大鼠5 d生存率分别为100%、24%、68%、56%,与B组相比,C、D组大鼠5 d生存率明显提高(P<0.05),C、D组间差异无统计学意义(P＞0.05);与B组相比,C、D组术后24 h和48 h血浆D-乳酸含量明显下降(P<0.01);与B组相比,C组、D术后24 h和48 h血浆DAO活性明显下降(P<0.01),C、D组术后24、48 h血浆D-乳酸含量、DAO活性差异无统计学意义(P＞0.05);电镜下C、D组肠黏膜上皮细胞损伤较B组明显减轻,细胞间紧密连接较清楚.结论 脓毒症时肠黏膜损伤严重,EP早期与延迟干预治疗能有效保护肠黏膜屏障,提高5 d生存率,具有抗脓毒症作用 .     

Levosimendan attenuates multiple organ injury and improves survival in peritonitis-induced septic shock: studies in a rat model

Introduction

The aim of this study was to investigate the effects of levosimendan on rodent septic shock induced by cecal ligation and puncture (CLP).

Methods

Three hours after peritonitis-induced sepsis, male Wistar rats were randomly assigned to receive an intravenous infusion of levosimendan (1.2 μg/kg/min for 10 min and then 0.3 μg/kg/min for 6 h) or an equivalent volume of saline and vehicle (5% dextrose) solution.

Results

The levosimendan-treated CLP animals had significantly higher arterial pressure and lower biochemical indices of liver and kidney dysfunction compared to the CLP animals (P < 0.05). Plasma interleukin-1β, nitric oxide and organ superoxide levels in the levosimendan-treated CLP group were less than those in CLP rats treated with vehicle (P < 0.05). In addition, the inducible nitric oxide synthase (iNOS) in lung and caspase-3 expressions in spleen were significantly lower in the levosimendan-treated CLP group (P < 0.05). The administration of CLP rats with levosimendan was associated with significantly higher survival (61.9% vs. 40% at 18 h after CLP, P < 0.05). At postmortem examination, the histological changes and neutrophil filtration index in liver and lung were significantly attenuated in the levosimendan-treated CLP group (vs. CLP group, P < 0.05).

Conclusions

In this clinically relevant model of septic shock induced by fecal peritonitis, the administration of levosimendan had beneficial effects on haemodynamic variables, liver and kidney dysfunction, and metabolic acidosis. (1) Lower levels of interleukin-1β, nitric oxide and superoxide, (2) attenuation of iNOS and caspase-3 expressions, and (3) decreases of neutrophil infiltration by levosimendan in peritonitis-induced sepsis animals suggest that anti-inflammation and anti-apoptosis effects of levosimendan contribute to prolonged survival.     

The role of intestinal mucosa injury induced by intra-abdominal hypertension in the development of abdominal compartment syndrome and multiple organ dysfunction syndrome

Introduction

Abdominal distension is common in critical illness. There is a growing recognition that intra-abdominal hypertension (IAH) may complicate nonsurgical critical illness as well as after abdominal surgery. However, the pathophysiological basis of the injury to the intestinal mucosal barrier and its influence on the onset of abdominal compartment syndrome (ACS) and multiorgan dysfunction syndrome (MODS) remain unclear. We measured intestinal microcirculatory blood flow (MBF) during periods of raised intra-abdominal pressure (IAP) and examined how this influenced intestinal permeability, systemic endotoxin release, and histopathological changes.

Methods

To test different grades of IAH to the injury of intestinal mucosa, 96 New Zealand white rabbits aged 5 to 6 months were exposed to increased IAP under nitrogen pneumoperitoneum of 15 mmHg or 25 mmHg for 2, 4 or 6 hours. MBF was measured using a laser Doppler probe placed against the jejunal mucosa through a small laparotomy. Fluorescein isothiocyanate (FITC)-conjugated dextran was administered by gavage. Intestinal injury and permeability were measured using assays for serum FITC-dextran and endotoxin, respectively, after each increase in IAP. Structural injury to the intestinal mucosa at different levels of IAH was confirmed by light and transmission electron microscopy.

Results

MBF reduced from baseline by 40% when IAP was 15 mmHg for 2 hours. This doubled to 81% when IAP was 25 mmHg for 6 hours. Each indicator of intestinal injury increased significantly, proportionately with IAP elevation and exposure time. Baseline serum FITC-dextran was 9.30 (± SD 6.00) μg/ml, rising to 46.89 (±13.43) μg/ml after 15 mmHg IAP for 4 hours (P <0.01), and 284.59 (± 45.18) μg/ml after 25 mmHg IAP for 6 hours (P <0.01). Endotoxin levels showed the same pattern. After prolonged exposure to increased IAP, microscopy showed erosion and necrosis of jejunal villi, mitochondria swelling and discontinuous intracellular tight junctions.

Conclusions

Intra-abdominal hypertension can significantly reduce MBF in the intestinal mucosa, increase intestinal permeability, result in endotoxemia, and lead to irreversible damage to the mitochondria and necrosis of the gut mucosa. The dysfunction of the intestinal mucosal barrier may be one of the important initial factors responsible for the onset of ACS and MODS.     

Interleukin 7 Transgenic Mice Develop Chronic Colitis with Decreased Interleukin 7 Protein Accumulation in the Colonic Mucosa

We have demonstrated that intestinal epithelial cells produce interleukin 7 (IL-7), and IL-7 serves as a potent regulatory factor for proliferation of intestinal mucosal lymphocytes expressing functional IL-7 receptor. To clarify the mechanism by which locally produced IL-7 regulates the mucosal lymphocytes, we investigated IL-7 transgenic mice. Here we report that transgenic mice expressing murine IL-7 cDNA driver by the SRα promoter developed chronic colitis in concert with the expression of SRα/IL-7 transgene in the colonic mucosa. IL-7 transgenic but not littermate mice developed chronic colitis at 4–12 wk of age, with histopathological similarity to ulcerative colitis in humans. Southern blot hybridization and competitive PCR demonstrated that the expression of IL-7 messenger RNA was increased in the colonic mucosal lymphocytes but not in the colonic epithelial cells. IL-7 protein accumulation was decreased in the goblet cell–depleted colonic epithelium in the transgenic mice. Immunohistochemical and cytokine production analysis showed that lymphoid infiltrates in the lamina propria were dominated by T helper cell type 1 CD4⁺ T cells. Flow cytometric analysis demonstrated that CD4⁺ intraepithelial T cells were increased, but T cell receptor γ/δ T cells and CD8α/α cells were not increased in the area of chronic inflammation. Increased IL-7 receptor expression in mucosal lymphocytes was demonstrated in the transgenic mice. These findings suggest that chronic inflammation in the colonic mucosa may be mediated by dysregulation of colonic epithelial cell–derived IL-7, and this murine model of chronic colitis may contribute to the understanding of the pathogenesis of human inflammatory bowel disease.     

Effect of β-sodium aescinate on hypoxia-inducible factor-1α expression in rat brain cortex after cardiopulmonary resuscitation

BACKGROUND:

This study was undertaken to investigate the expression of hypoxia-inducible factor-1α (HIF-1α) in rat cerebral cortex and the effects of β-sodium aescinate (SA) administration after return of spontaneous circulation (ROSC).

METHODS:

Sixty rats were divided into three groups: SA group, injected intraperitoneally with SA instantly after ROSC; control group, injected intraperitoneally with normal saline; and sham-operated group, without cardiac arrest or SA. The cardiac arrest model was established using asphyxiation and intravenous potassium chloride. Blood was sampled 1, 6, 12, and 24 hours after ROSC. Protein and mRNA levels of HIF-1α, VEGF and EPO were detected in the cerebral cortex by immunohistochemistry and real-time RT-PCR; serum levels of NSE and S100β were determined by enzyme-linked immunosorbent assays.

RESULTS:

Serum S100β and NSE were significantly increased in the control group versus the sham-operated group 1, 6, 12 and 24 hours after ROSC (P<0.05). Protein and mRNA levels of HIF-1α, VEGF and EPO were significantly increased in the control rats (P<0.05). Serum NSE and S100β were significantly decreased in the SA group versus the control group 1, 6, 12 and 24 hours after ROSC (P<0.05). Protein and mRNA levels of HIF-1α, VEGF and EPO were significantly increased in the SA group (P<0.05).

CONCLUSIONS:

The expression of HIF-1α is increased in rat cerebral cortex after ROSC, and SA up-regulates the expression of HIF-1α. The up-regulation of HIF-1α improves the resistance of the cortex to ischemia and hypoxia and contributes to neuroprotection, possibly because of up-regulation of EPO and VEGF expression.KEY WORDS: Cardiopulmonary resuscitation, HIF-1α, Erythropoietin, Vascular endothelial growth factor, β-sodium aescinate, Neuroprotection     

Influence of cyclooxygenase inhibitors on gut immune cell distribution and apoptosis rate in experimental sepsis

The aim of this study was to determine if cyclooxygenase (COX) inhibitors influence immune cell distribution in the small intestinal mucosa and mesenteric lymph nodes (MLNs), the grade of mucosal damage, and the rate of apoptosis in septic rats. The effects induced by a selective COX-2 inhibitor (SC-236) were compared with those of a nonselective COX-1 and -2 inhibitor (indomethacin). Cecal ligation and puncture (CLP), CLP + SC-236 p.o, and CLP + indomethacin p.o, were evaluated. Animals were harvested 6 and 24 h after CLP, respectively. The concentration of proinflammatory cytokines was higher in ascitic fluid than in blood. CLP + SC-236 attenuated IL-6 in plasma and in ascitic fluid and CLP + indomethacin augmented TNF-alpha in ascitic fluid compared with CLP at 6 h. CLP + SC-236 gave a lesser degree of mucosal damage compared with CLP alone or with indomethacin at 6 and 24 h (P < 0.05). Untreated CLP had significant reductions in the number of T lymphocytes in the villi and increases of macrophages in the mucosa and MLNs compared with controls (P < 0.05). CLP + indomethacin decreased T lymphocytes in the villi and MLNs. CLP caused an enhanced apoptosis in the mucosa compared with controls (P < 0.05), pretreatment with COX inhibitors did not significantly change this. Both COX inhibitors enhanced apoptosis in MLNs and attenuated the increase of macrophages in mucosa and MLNs (P < 0.05). It is proposed that the increased apoptosis and the decrease in T cells in the mucosa may be causally related. Apoptosis of lymphocytes may impair the immunologic defense in sepsis. Furthermore, loss of intestinal epithelial cells may compromise bowel wall integrity and facilitate translocation.     

Protective role of fenofibrate in sepsis-induced acute kidney injury in BALB/c mice

Acute kidney injury (AKI) is a severe complication of sepsis, which largely contributes to the associated high mortality rate. Fenofibrate, a peroxisome proliferator activated receptor α (PPARα) agonist, has received considerable attention because of its effects related to renal damage-related energy metabolism and inflammation. The present study investigated the effects of fenofibrate on sepsis-associated AKI in BALB/c mice subjected to caecal ligation and puncture (CLP). Eight-week-old male BALB/c mice were divided into four groups: control group, fenofibrate group, caecal ligation and puncture (CLP) group, and fenofibrate + CLP group. CLP was performed after mice were gavaged with fenofibrate for 2 weeks. After 48 hours, we measured the histopathological alterations of the kidney tissue and plasma levels of serum creatinine (CRE), neutrophil gelatinase-associated lipocalin (NGAL), reactive oxygen species (ROS), ATP, and ADP. We evaluated PPARα and P53 protein levels as well as interleukin (IL)-1β, IL-6, and tumour necrosis factor-α mRNA levels. Our results showed that administering fenofibrate significantly reduced kidney histological alterations caused by CLP. Fenofibrate inhibited the plasma levels of ROS, CRE, NGAL, and increased the ATP/ADP ratio. Fenofibrate significantly inhibited elevations in P53, IL-1β, IL-6, and tumour necrosis factor-α expression. The results suggest that fenofibrate administration effectively modulates energy metabolism and may be a novel approach to treat sepsis-induced renal damage.

Acute kidney injury (AKI) is a severe complication of sepsis, which largely contributes to the associated high mortality rate.     

Functional changes of intestinal mucosal barrier in surgically critical patients

BACKGROUND:

The gut is capable of inducing multiple organ dysfunction syndrome (MODS). In the diagnosis and treatment of critical ill patients, doctors should pay particular attention to the protection or recovery of intestinal barrier function. However, no reliable diagnostic criteria are available clinically. This study aimed to assess the changes of intestinal mucosal barrier function in surgically critical ill patients as well as their significance.

METHODS:

Thirty-eight surgically critical ill patients were enrolled as a study group (APACHE II>8 scores), and 15 non-critical ill patients without intestinal dysfunction were selected as a control group (APACHE II<6). General information, symptoms, physical signs, and APACHE II scores of the patients were recorded. The patients in the study group were subdivided into an intestinal dysfunction group (n=26) and a non-intestinal dysfunction group (n=12). Three ml venous blood was collected from the control group on admission and the same volume of plasma was collected from the study group both on admission and in the period of recovery. The plasma concentrations of endotoxin, diamine oxidase (DAO), D-lactate, and intestinal fatty-acid binding protein (iFABP) were detected respectively. The data collected were analyzed by the SPSS 17.0 software for Windows.

RESULTS:

The levels of variables were significantly higher in the study group than in the control group (P<0.01). They were higher in the intestinal dysfunction group than in the non-intestinal dysfunction group (DAO P<0.05, endotoxin, D-lactate, iFABP P<0.01). In the non-intestinal dysfunction group compared with the control group, the level of endotoxin was not significant (P>0.05), but the levels of DAO, D-lactate and iFABP were statistically significant (P<0.05). The levels of variables in acute stage were higher than those in recovery stage (P<0.01). The death group showed higher levels of variables than the survival group (endotoxin and D-lactate P<0.01, DAO and iFABP P<0.05).

CONCLUSION:

The plasma concentrations of endotoxin, DAO, D-lactate, and intestinal fatty-acid binding protein (iFABP) could reflect a better function of the intestinal mucosa barrier in surgically critical ill patients.KEY WORDS: Intestinal mucosal barrier, Endotoxin, Diamine oxidase, D-lactate, Intestinal fatty-acid binding protein     

大鼠休克复苏后肠黏膜屏障特点的探讨

目的 探讨失血性休克肠缺血．再灌注损伤后黏膜屏障的形态学、功能与重建的特点。方法 制作大鼠失血性休克模型，于复苏后0、1、3、6、12、24h时间段活杀并进行光镜和电镜下肠黏膜组织形态学观察、内毒素含量及尿液乳果糖，甘露醇比值的测定。结果 肠黏膜主要表现为凋亡和坏死两种损伤形式，大部分肠黏膜于6h重建，12h结构基本恢复正常，肠杯状细胞数在各组呈下降趋势；内毒素和乳果糖，甘露醇比值在6h达高峰。结论 失血性休克后肠黏膜屏障早期受累，但同时具有快速重建能力；屏障功能的恢复滞后于形态学重建。     

Intravenous glutamine decreases lung and distal organ injury in an experimental model of abdominal sepsis

Introduction

The protective effect of glutamine, as a pharmacological agent against lung injury, has been reported in experimental sepsis; however, its efficacy at improving oxygenation and lung mechanics, attenuating diaphragm and distal organ injury has to be better elucidated. In the present study, we tested the hypothesis that a single early intravenous dose of glutamine was associated not only with the improvement of lung morpho-function, but also the reduction of the inflammatory process and epithelial cell apoptosis in kidney, liver, and intestine villi.

Methods

Seventy-two Wistar rats were randomly assigned into four groups. Sepsis was induced by cecal ligation and puncture surgery (CLP), while a sham operated group was used as control (C). One hour after surgery, C and CLP groups were further randomized into subgroups receiving intravenous saline (1 ml, SAL) or glutamine (0.75 g/kg, Gln). At 48 hours, animals were anesthetized, and the following parameters were measured: arterial oxygenation, pulmonary mechanics, and diaphragm, lung, kidney, liver, and small intestine villi histology. At 18 and 48 hours, Cytokine-Induced Neutrophil Chemoattractant (CINC)-1, interleukin (IL)-6 and 10 were quantified in bronchoalveolar and peritoneal lavage fluids (BALF and PLF, respectively).

Results

CLP induced: a) deterioration of lung mechanics and gas exchange; b) ultrastructural changes of lung parenchyma and diaphragm; and c) lung and distal organ epithelial cell apoptosis. Glutamine improved survival rate, oxygenation and lung mechanics, minimized pulmonary and diaphragmatic changes, attenuating lung and distal organ epithelial cell apoptosis. Glutamine increased IL-10 in peritoneal lavage fluid at 18 hours and bronchoalveolar lavage fluid at 48 hours, but decreased CINC-1 and IL-6 in BALF and PLF only at 18 hours.

Conclusions

In an experimental model of abdominal sepsis, a single intravenous dose of glutamine administered after sepsis induction may modulate the inflammatory process reducing not only the risk of lung injury, but also distal organ impairment. These results suggest that intravenous glutamine may be a potentially beneficial therapy for abdominal sepsis.     

Effects of selective β1-adrenoceptor blockade on cardiovascular and renal function and circulating cytokines in ovine hyperdynamic sepsis

Introduction

Activation of the sympathetic nervous system has beneficial cardiovascular effects in sepsis, but there is also evidence that sympatholytics have beneficial actions in sepsis. We therefore determined the effect of selective β₁-adrenoceptor blockade on cardiac and renal function and cytokine release in ovine hyperdynamic sepsis.

Methods

Hyperdynamic sepsis was induced by infusion of live E. coli for 24 hours in nine conscious sheep instrumented with flow probes on the pulmonary and left renal artery. Cardiovascular and renal function and levels of plasma cytokines were determined in a control group and during selective β1-adrenoceptor blockade with atenolol (10 mg intravenous bolus then 0.125 mg/kg/h) from 8 to 24 hours of sepsis.

Results

Hyperdynamic sepsis was characterized by hypotension with increases in cardiac output (CO), heart rate (HR) and renal blood flow (RBF), and acute kidney injury. Atenolol caused sustained reductions in HR (P <0.001) and CO (P <0.001). Despite the lower CO the sepsis-induced fall in mean arterial pressure (MAP) was similar in both groups. The sepsis-induced increase in RBF, decrease in renal function and increase in arterial lactate were unaffected by atenolol. Sepsis increased plasma levels of tumour necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and IL-10. Atenolol caused a further increase in IL-10, but did not affect levels of TNF-α or IL-6.

Conclusions

In sepsis, selective β₁-adrenoceptor blockade reduced CO, but not MAP. During sepsis, atenolol did not alter the development of acute kidney injury or the levels of pro-inflammatory cytokines, but enhanced the release of IL-10. Atenolol appears safe in sepsis, has no deleterious cardiovascular or renal effects, and has an anti-inflammatory effect.