Pioglitazone attenuates lung injury by modulating adipose inflammation

Background

Pioglitazone modulates adipocyte differentiation and enhances adiponectin promoter activity to increase plasma adiponectin levels. We investigated the effects of pioglitazone on cecal ligation and puncture (CLP)-induced visceral-adipose-tissue inflammation and lung injury in mice.

Materials and methods

Eight-wk-old male mice were assigned to three groups: (1) a sham-operated control group, (2) a CLP group, and (3) a pioglitazone-treated CLP group. Pioglitazone (10 mg/kg) was injected intraperitoneally for 7 d. Serum, lung, and visceral adipose tissue were collected 24 h after surgery. Tumor necrosis factor α (TNF-α) levels in peritoneal lavage fluid were measured by an enzyme-linked immunosorbent assay, and TNF-α and interleukin 6 messenger RNA (mRNA) expression levels in visceral adipose tissue were quantified by real-time polymerase chain reaction. Lung tissue specimens were stained with hematoxylin-eosin, and the terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling method was used to evaluate tissue damage.

Results

TNF-α levels in peritoneal lavage fluid were significantly higher in the CLP group than in the sham group. TNF-α levels in the pioglitazone-treated CLP group were significantly lower than those in the CLP group. TNF-α and interleukin 6 mRNA expression levels of visceral adipose tissue were significantly higher in the CLP group than in the sham group. Pioglitazone treatment decreased the mRNA expression levels of these cytokines compared with the respective values in the CLP group. Histopathologic analysis of lung tissue revealed significantly increased numbers of terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling–positive cells in the CLP group compared with the sham group.

Conclusions

Pioglitazone effectively prevents lung injury caused by CLP-induced sepsis by maintaining the anti-inflammatory status of visceral adipose tissue.     

Tumor necrosis factor-alpha preconditioning attenuates liver ischemia/reperfusion injury through preserving sarco/endoplasmic reticulum calcium-ATPase function

Background

Tumor necrosis factor-alpha (TNF-α) is a multifunctional cytokine. In this study, we investigated the role of TNF-α preconditioning in liver ischemia/reperfusion injury (IRI).

Methods

After IRI, serum alanine aminotransferase, protein levels of SERCA-3, and Caspase-3 in liver were analyzed. In vitro study, primary hepatocytes were isolated from mice and cultured in hypoxic media with or without TNF-α. The levels of SERCA-3, Caspase-3, and intracellular calcium were evaluated after 24-h incubation. In addition, protease inhibitors were adopted to determine the role of SERCA-3 in TNF-α preconditioning.

Results

Low dose of TNF-α preconditioning protected liver from IRI, which was described by reduced serum alanine aminotransferase, Capase-3, and elevated SERCA-3 compared with the animals without TNF-α treatment. The in vitro test confirmed the protective effect of TNF-α through maintaining homeostasis of intracellular calcium. However, the effect of TNF-α was deprived by protease inhibitors.

Conclusions

In this study, we demonstrated that IRI reduced SERCA-3 expression in liver. Low dose of TNF-α preconditioning protected against SERCA-3 reducing, promoted intercellular calcium storage, and attenuated liver IRI.     

丙酮酸乙酯对脓毒症大鼠肠组织保护和HMGB1表达的影响

目的:通过观察丙酮酸乙酯对脓毒症大鼠肠组织HMGB1表达的影响,进一步揭示丙酮酸乙酯治疗脓毒症的分子作用机制。方法:将96只SD大鼠随机分为假手术组、脓毒症组、低剂量丙酮酸乙酯治疗组(LET组)、高剂量丙酮酸乙酯治疗组(ET组),以盲肠结扎穿刺法复制大鼠脓毒症模型。LET组(20 mg/kg)及ET组(40 mg/kg)即刻腹腔内注射EP注射液4 mL,每6 h重复注射一次,直至实验结束,假手术组及脓毒症组在相同时间用相同剂量的生理盐水腹腔内注射。各组大鼠分别于术后2 h、8 h、24 h、48 h 4个时间点随机处死6只大鼠,经腹主动脉取血,用ELISA方法检测血浆TNF-α、IL-6、HMGB1水平。术后24 h,取大鼠末端回肠,用RT-PCR法检测回肠组织HMGB1mRNA表达水平,用免疫组织化学两步方法观察肠组织HMGB1蛋白表达,在光镜下观察大鼠肠组织的病理变化。结果:与假手术组相比,脓毒症组血浆HMGB1在术后8 h、24 h、48 h显著增高,脓毒症组回肠组织HMGB1mRNA及蛋白表达在术后24 h显著增高(P0.05)。与脓毒症组相比,ET组、LET组血浆HMGB1在术后8 h、24 h、48 h显著降低,ET组、LET组回肠组织HMGB1mRNA及蛋白表达在术后24h显著降低(P0.05)。结论:脓毒症大鼠血浆HMGB1出现时间晚,作用时间长,提示HMGB1是脓毒症的重要晚期炎症介质。丙酮酸乙酯可抑制脓毒症大鼠血浆及肠组织HMGB1的表达,提示丙酮酸乙酯对脓毒症的治疗机制可能与其直接或间接抑制HMGB1的表达有关。     

Role of neutrophil elastase in lung injury induced by burn–blast combined injury in rats

Objective

Neutrophil elastase (NE) takes part in the pathogenesis of acute lung injury. However, its role in lung injury of burn–blast combined injury is unclear. Our objective was to assess the role of NE, and effect of sivelestat, a specific NE inhibitor, in lung injury induced by burn–blast combined injury in rats.

Methods

One hundred and sixty male Sprague-Dawley rats were randomly subjected to burn–blast combined injury (BB) group, burn–blast combined injury plus sivelestat treatment (S) group or control (C) group. Blood gas, protein concentration and NE activity in bronchoalveolar lavage fluid (BALF), pulmonary myeloperoxidase (MPO) activity, serum concentrations of TNF-α and IL-8, etc. were investigated from 0 h to 7 d post-injury.

Results

In BB group, PaO₂ decreased, while NE activity in BALF, total protein concentration in BALF, pulmonary MPO activity and W/D ratio, serum concentrations of TNF-α and IL-8 increased with neutrophil infiltration, progressive bleeding and pulmonary oedema. Compared with BB group, sivelestat treatment decreased the NE activity and ameliorated the above indexes.

Conclusion

Sivelestat, exerts a protective effect in lung injury after burn–blast combined injury through inhibiting NE activity to decrease pulmonary vascular permeability, neutrophil sequestration, and production of TNF-α and IL-8.     

(Pro)renin receptor blocker improves survival of rats with sepsis

Background

The renin-angiotensin system (RAS) affects inflammatory responses during sepsis. Nonproteolytic activation of prorenin by the (pro)renin receptor has recently been shown to stimulate the tissue RAS. In the present study, the effect of (pro)renin receptor blocker (PRRB) pretreatment on sepsis in a rat cecal ligation and puncture (CLP) model was investigated.

Materials and methods

Male Sprague-Dawley rats underwent CLP and were randomly divided into two groups: PRRB-treated group and control peptide–treated group. Survival was analyzed for 7 d after CLP. The serum concentrations of cytokines and high-mobility group box chromosomal protein 1 (HMGB1) were measured at three time points (0, 3, and 6 h after CLP). Hematoxylin-eosin staining and immunohistochemical staining for nonproteolytically activated prorenin and HMGB1 were performed on the cecum to assess pathologic changes found 6 h after CLP.

Results

Treatment with PRRB improved the survival rate of the post-CLP septic rats (P = 0.023). PRRB also significantly reduced serum tumor necrosis factor-α, interleukin-1β, and HMGB1 levels 6 h after CLP. In CLP rats that were treated with control peptide, the expression of activated prorenin was elevated in peritoneal foam cells. Moreover, expression of HMGB1 was increased in peritoneal inflammatory cells. In contrast, both were markedly suppressed in CLP rats that were treated with PRRB.

Conclusions

PRRB significantly improved the survival rate of rats with clinically relevant sepsis, possibly by attenuating a sepsis-induced systemic inflammatory response. We propose that overactivation of the RAS by activation of prorenin in foam cells may be a significant contributor to sepsis.     

The manner of the inflammation-boosting effect caused by acute hyperglycemia secondary to overfeeding and the effects of insulin therapy in a rat model of sepsis

Background

The aim of the study was to investigate both the inflammation-boosting effect and the metabolic stress induced by acute hyperglycemia secondary to overfeeding with excessive glucose infusion and the effects of insulin therapy on those events in a rat model of sepsis.

Materials and methods

Sprague–Dawley rats underwent cecal ligation and puncture (CLP) or sham operation. Preestablished continuous intravenous glucose infusion was initiated immediately after surgery. First, rats with CLP-inducing sepsis were divided into three groups on the basis of the target blood glucose (BG) levels: high glucose (HG) group (overfed, >300 mg/dL), moderate glucose group (moderate hyperglycemia, 200–300 mg/dL), and no glucose group (100–150 mg/dL). The sham group received the same glucose infusion as that of the HG group. BG and plasma interleukin (IL) 6 levels were monitored over time. All rats were sacrificed 9 h after surgery to evaluate lung histology and measure hepatic total glutathione and malondialdehyde contents. Based on the results, the high glucose and insulin (HI) group was added to septic groups as a model of insulin therapy, in which insulin with the same HG dose as that in the HG group was administered to maintain moderate hyperglycemia.

Results

BG level in all groups remained in the preestablished target range throughout the experiment. Plasma IL-6 level in all septic groups increased in a time-dependent manner, whereas that in the sham group with moderate hyperglycemia hardly increased. Nine hours after CLP, plasma IL-6 level in the HG group rose to 7407.5 ± 1987.3 pg/mL, which was three times higher than that in the other septic groups. There was no significant difference among moderate glucose, no glucose, and HI groups, in which BG level remained constant at <300 mg/dL. The HG group showed the worst consequences of lung injury and oxidative stress in the liver, which were completely stable in HI group.

Conclusions

Acute severe hyperglycemia in critical illness might excessively boost the existing systemic inflammatory response in a threshold-based manner. Insulin therapy under overfeeding could strongly inhibit such a boosting effect and oxidative stress in the liver.     

δ阿片受体激动剂对脓毒症大鼠细胞免疫功能的影响

目的 探讨δ阿片受体激动剂对脓毒症大鼠细胞免疫功能的影响.方法 健康成年雄性SD大鼠150只,体重154～198g,随机分为3组(n=50):假手术组(S组)仅穿线,不进行盲肠结扎穿孔;脓毒症组(SEP组)采用盲肠结扎穿孔的方法制备脓毒症模型;δ阿片受体激动剂组(DADLE组)于盲肠结扎穿孔后立即腹腔注射δ阿片受体激动剂DALDE 10 ml/kg,浓度为0.5 mg/ml.于盲肠结扎穿孔后4、8、12 h(T1～3)时各组随机取10只大鼠,抽取下腔静脉血样,采用ELISA法检测血清TNF-α和IL-10的浓度,采用流式细胞仪检测T淋巴细胞亚群变化.记录盲肠结扎穿孔后7 d内大鼠的生存情况.结果 与S组比较,SEP组和DADLE组各时点血清TNF-α和IL-10的浓度、TNF-α/lL-10比值升高,T3时CD4+T细胞水平和CD4+/CD8+降低,CD8+T细胞水平升高(P＜0.05或0.01);与SEP组比较,DADLE组T2.3时血清TNF-α和IL-10的浓度、TNF-α/IL-10比值降低,T3时CD4+T细胞水平和CD4+/CD8+升高,CD8+T细胞水平降低,盲肠结扎穿孔后7 d内大鼠生存率升高(P＜0.05).结论 δ阿片受体激动剂可改善细胞免疫功能,从而减轻炎性反应,有利于脓毒症大鼠的预后.     

Functions of aquaporin 1 and α-epithelial Na+ channel in rat acute lung injury induced by acute ischemic kidney injury

Purpose

To establish a rat model of acute ischemic kidney injury by continually occluding the bilateral renal artery and renal veins, the functions of α-epithelial Na⁺ channel (α-ENaC) and aquaporin (AQP1) in lung injury induced by acute kidney injury (AKI) were examined and compared with lung injury induced by endotoxin.

Methods

Male Wistar rats were randomly divided into three groups: control group, AKI group, and sepsis group. The concentrations of AQP1 and α-ENaC in the lung tissue were detected. The concentrations of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in the serum and bronchoalveolar lavage fluid were also detected.

Results

The arterial blood pH in AKI group and PaO₂ in sepsis group decreased 2 h after the experiment. A significant pulmonary interstitial and alveolar space edema, which showed a typical pathological change in acute lung injury, was found in AKI and sepsis group 8 h after the experiment. Two hours after the experiment, the concentration of TNF-α and IL-6 in the serum and bronchoalveolar lavage fluid (BALF) in AKI and sepsis group increased, whereas the pulmonary expression of AQP1 and α-ENaC decreased. The pulmonary AQP1 and α-ENaC of the rats were negatively correlated with TNF-α and IL-6 in BALF. The relevance among AQP1, α-ENaC, TNF-α, and IL-6 in sepsis group was higher than that in AKI group.

Conclusion

The TNF-α and IL-6 levels increased significantly and the pulmonary expression of AQP1 and α-ENaC declined at the early stage of AKI.     

脓毒症大鼠肾脏AQPs动态变化与水代谢的关系

目的：探讨肾脏AQPs的表达与肾损伤水代谢紊乱的关系。方法：Wistar大鼠采用盲肠结扎穿孔法（CLP）建立脓毒症大鼠模型。观测尿量、尿渗透压和肾功能。免疫组化方法检测AQP1、AQP2蛋白水平,实时荧光定量PCR方法检测AQP1mRNA、AQP2mRNA水平。结果：手术组大鼠肾脏AQP1蛋白及AQP1mRNA表达随着CPL术后时间的延长呈下降趋势,6h开始下降,24h达最低;AQP2蛋白及AQP2-mRNA表达均在术后3h增高、12h、24h明显降低,较假手术组差异有统计学意义（P〈0.05）。大鼠肾脏AQP1、AQP2分别与尿量呈负相关（P〈0.05）,与尿渗透压呈正相关（P〈0.05）。结论：AQP1和AQP2基因通过调节AQP1、AQP2蛋白的表达,参与肾脏水代谢的调节;AQP1、AQP2蛋白及基因的表达异常是导致脓毒症肾损伤水代谢紊乱的重要原因。     

七氟醚对感染性休克大鼠全身炎性反应及心肺功能的影响

目的 评价七氟醚对感染性休克大鼠全身炎性反应及心肺功能的影响.方法 清洁级SD大鼠32只,体重250～300 g,月龄8～10月,雌雄各半,随机分为4组(n=8):假手术组(S组)仅开腹,不行盲肠结扎穿孔(CLP);感染性休克组(CLP组)采用CLP法建立感染性休克模型;七氟醚I组(SEV1组)感染性休克后1 h时吸入2.4%七氟醚30 min;七氟醚Ⅱ组(SEV2组)感染性休克后3 h时吸入2.4%七氟醚30 min.于感染性休克后1、3、5 h时记录MAP和HR,并采集动脉血样1.5ml,取0.3 ml血样行血气分析,剩余1.2 ml血样检测血浆肿瘤坏死因子α(TNF-α)、白细胞介素1(IL-1)、丙二醛(MDA)及一氧化氮(NO)的浓度.于感染性休克后5 h时测定心功能,记录心脏左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)、左心室短轴缩短率(LVFS)和心输出量(CO).心功能测定后处死动物,取肺组织,计算肺湿干重比(W/D),测定伊文氏兰(EB)含量;取心、肺、肝、肾组织,检测NF-κB活性.结果 与s组比较,CLP组、SEV1组和SEV2组MAP降低,HR增快,LVEDD、LVESD、LVFS、CO、pH值、PaOz和PaCO2降低,肺W/D、EB含量、血浆TNF-α、IL-1、MDA和NO的浓度增加,心、肺、肝、肾组织的NF-κB活性升高(P<0.05).与CLP组和SEV2组比较,SEV1组心、肺、肝、肾组织的NF-κB活性和血浆TNF-α、IL-1、MDA和NO的浓度降低(P<0.05),其余各指标差异无统计学意义(P>0.05).结论 感染性休克后1 h大鼠吸入2.4%七氟醚30 min可抑制全身炎性反应,但抑制程度较低,不足以改善心肺功能.     

L-alpha-glycerylphosphorylcholine reduces the microcirculatory dysfunction and nicotinamide adenine dinucleotide phosphate-oxidase type 4 induction after partial hepatic ischemia in rats

Background

We set out to investigate the microcirculatory consequences of hepatic ischemia–reperfusion (IR) injury and the effects of L-alpha-glycerylphosphorylcholine (GPC), a deacylated phospholipid derivative, on postischemic hepatocellular damage, with special emphasis on the expression of nicotinamide adenine dinucleotide phosphate oxidase type 4 (NOX4), which is predominantly expressed in hepatic microvessels.

Materials and methods

Anesthetized male Sprague–Dawley rats were subjected to 60-min ischemia of the left liver lobes and 180-min reperfusion, with or without GPC treatment (50 mg/kg intravenously 5 min before reperfusion, n = 6 each). A third group (n = 6) served as saline-treated control. Noninvasive online examination of the hepatic microcirculation was performed hourly by means of modified spectrometry. Plasma tumor necrosis factor (TNF-α), high-mobility group box 1 protein (HMGB1), plasma aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase levels, tissue xanthine oxidoreductase (XOR) and myeloperoxidase (MPO) activities, and expressions of NOX2 and NOX4 proteins were determined.

Results

Liver IR resulted in significant increases in NOX2 and NOX4 expressions and XOR and MPO activities, and approximately 2-fold increases in the levels of the inflammatory cytokines TNF-α and HMGB1. The microvascular blood flow and tissue oxygen saturation decreased by ∼20% from control values. GPC administration ameliorated the postischemic microcirculatory deterioration and reduced the liver necroenzyme levels significantly; the NOX4 expression, MPO activity, and HMGB1 level were also decreased, whereas the NOX2 expression, TNF-α level, and XOR activity were not influenced by GPC pretreatment.

Conclusions

NOX4 activation is a decisive component in the IR-induced microcirculatory dysfunction. Exogenous GPC ameliorates the inflammatory activation, and preserves the postischemic microvascular perfusion and liver functions, these effects being associated with a reduced hepatic expression of NOX4.     

Interleukin-17A plays a pivotal role after partial hepatectomy in mice

Background

Liver regeneration after partial hepatectomy (PH) is regulated by tumor necrosis factor (TNF)-α derived from the Kupffer cell. Furthermore, it was reported from our laboratory that interleukin (IL)-17A enhances the production of TNF-α by the Kupffer cell, suggesting that IL-17A may play a role in liver regeneration.

Objective

The purpose was to determine the role of IL-17A and the spleen in liver regeneration after PH.

Methods

Two mouse models including the wild-type (WT) mice or the IL-17A knockout (KO) mice underwent PH. Animals were killed at the designated time points; liver tissues were harvested for further investigation. Proliferation of hepatocytes was evaluated. Furthermore, the messenger RNA and protein expression of TNF-α and IL-6 were measured in the liver. In another set of experiments, the two animal models underwent splenectomy before PH. In an in vitro study, CD4-positive lymphocytes in the spleen were isolated from mice, and the number of IL-17A–positive cells was investigated.

Results

Liver regeneration was significantly impaired in the KO mice compared with the WT mice. This was associated with suppression of cell proliferation assessed by cell proliferation markers in the KO mice. In the WT mice that underwent splenectomy, liver regeneration was significantly delayed compared with animals without splenectomy. In contrast, splenectomy did not affect liver regeneration in the KO mice. IL-17A–positive lymphocytes increased significantly in the spleen in the WT mice after PH.

Conclusions

These results indicate that IL-17A derived from CD4-positive lymphocytes in the spleen is a key regulator in liver regeneration after PH.     

Effects of Phosphodiesterase Inhibitors on the Inflammatory Response of Endothelial Cells Stimulated by Myeloperoxidase-Modified Low-Density Lipoprotein or Tumor Necrosis Factor Alpha

Background

Sildenafil, vardenafil, and tadalafil are phosphodiesterase type 5 inhibitors (PDE5-Is) usually used in the treatment of erectile dysfunction (ED). Previously, we have shown the presence of myeloperoxidase-modified low-density lipoprotein (Mox-LDL) in the penises of patients with ED, and we have shown the impact of Mox-LDL on cyclic monophosphate (cGMP) level. In vitro, Mox-LDL triggered the inflammatory response by increasing the release of both interleukin 8 (IL-8) and tumor necrosis factor alpha (TNF-α) by endothelial cells (ECs) and monocytes respectively.

Objective

To determine whether or not the three therapeutically PDE5-Is protect against the proinflammatory effects of Mox-LDL or TNF-α on ECs.

Design, setting, and participants

ECs (EA.hy926) were incubated in the presence of either TNF-α (100 pg/ml) or Mox-LDL (200 μg/ml) with each of the three PDE5-Is (1 μM, 5 μM, and 10 μM) respectively. IL-8 production was measured in the supernatant after 48 h of incubation.

Measurements

All experiments were repeated at least three times. Statistical analysis was performed with an ANOVA.

Results and limitations

Two-way ANOVA analysis showed that TNF-α alone (p < 0.001) or Mox-LDL alone (p < 0.001) increased IL-8 production. Sildenafil, vardenafil, or tadalafil alone did not generate an increase of IL-8 production. Tadalafil in combination with Mox-LDL and TNF-α showed a decrease of IL-8 (p < 0.05) compared with sildenafil and vardenafil.

Conclusions

Among the three available PDE5-Is, tadalafil showed an additional potentially anti-inflammatory effect on relaxation. Those data could be considered for the chronic use of PDE5-Is, but extrapolations of experimental evidence to the clinical setting should be made cautiously.     

Thalidomide prolongs survival after experimental musculoskeletal injury,through an effect on mononuclear apoptosis

Background

This study was conducted to investigate the effects of intravenous thalidomide administration in an experimental model of musculoskeletal trauma. We hypothesized that because thalidomide inhibits secretion of tumor necrosis factor alpha (TNF-α), survival of animals that received thalidomide would be significantly prolonged.

Material and methods

After an open fracture of the right femur, 24 rabbits were randomly assigned to control and thalidomide groups. Intravenous therapy with thalidomide was started 30 min after fracture. Hemodynamic monitoring of all animals was performed for 4 h. Survival was recorded and bacterial growth in blood and organs was measured after animal death or sacrifice. Blood was sampled for TNF-α measurement and for isolation of peripheral blood mononuclear cells (PBMCs). Apoptosis of PBMCs was measured by flow cytometry.

Results

Survival was significantly prolonged in the thalidomide group. Apoptosis of PBMCs was increased in the control group compared with the thalidomide group at 24 h. There were no differences in vital signs, blood and tissue cultures, and serum TNF-α concentration between the two groups.

Conclusions

Intravenous thalidomide prolonged survival in an experimental model of severe musculoskeletal injury in rabbits. Its mechanism of action did not involve TNF-α suppression but prevention of mononuclear apoptosis. In view of these promising results, further research is needed to clarify the immunomodulatory mechanism of action of thalidomide and its potential use for the management of severe trauma.     

Inhibition of histone deacetylases protects septic mice from lung and splenic apoptosis

Background

Epigenetic programming, dynamically regulated by histone acetylation, may play a key role in the pathophysiology of sepsis. We examined whether histone deacetylase (HDAC) can contribute to sepsis-associated inflammation and apoptosis.

Materials and methods

Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) in BALB/c mice. An intraperitoneal injection of CG200745 (10 mg/kg), a novel broad-spectrum HDAC inhibitor, or valproic acid (500 mg/kg), a predominant inhibitor of class I HDACs, was given 3 h before surgery.

Results

HDAC1, HDAC2, and HDAC3 protein levels were decreased in lungs after CLP. Furthermore, CLP-induced sepsis increased both histone H3 and H4 acetylation levels in lungs. When CG200745 was given, apoptosis induction was strongly suppressed in lungs and spleens of septic mice. This antiapoptotic effect of CG200745 was not accompanied by upregulation of antiapoptotic and downregulation of proapoptotic Bcl-2 family member proteins. Treatment with CG200745 failed to inhibit elevated levels of serum cytokines and prevent lung inflammation in septic mice. Valproic acid also showed antiapoptotic but not anti-inflammatory effects in septic mice.

Conclusions

These findings imply that HDAC inhibitors are a unique agent to prevent cell apoptosis in sepsis at their doses that do not improve inflammatory features, indicating that septic inflammation and apoptosis may not necessarily be essential for one another's existence. This study also represents the first report that CLP-induced sepsis downregulates HDACs. Nevertheless, the data with HDAC inhibitors suggest that imbalance in histone acetylation may play a contributory role in expression or repression of genes involved in septic cell apoptosis.     

一种改良小鼠脓毒症模型的建立

目的 建立一种模拟外科临床实际,早期致死率低,用于脓毒症综合治疗研究的小鼠模型.方法 小鼠随机分为3组,即对照组、盲肠结扎穿孔(CLP)组和改良组.对照组行假手术;CLP组行盲肠结扎穿孔术;改良组通过CLP后8 h行盲肠切除和腹腔生理盐水冲洗建立脓毒症模型.观察各组动物出现死亡时间及24、48、72 h累计死亡率;术后4、12、24 h分别处死动物,检测外周血白细胞计数(VC-BC),血清内毒素、肿瘤坏死因子(TNF)水平及肺、肝病理.结果 改良组动物出现死亡时间较CLP组明显延迟,术后48、72 h累计死亡率虽明显低于CLP组(P＜0.05),但仍分别高达53.3%、80%;术后各时间点WBC较CLP组与假手术组明显升高(P＜0.05);血清内毒素和TNF-α水平明显高于假手术组,但低于CLP组;光镜下见肺泡间隔增宽,间质充血、水肿、大量炎性细胞浸润,肝细胞水肿伴散在点状坏死,肝窦扩张伴间质大量炎性细胞浸润.结论 该脓毒症改良模型具有良好的外科临床相关性,早期致死率低,可重复性好.     

Polymicrobial sepsis is associated with decreased hepatic oxidative phosphorylation and an altered metabolic profile

Background

Organ failure in sepsis accounts for significant mortality worldwide. Mitochondrial and metabolic responses are central to the overall response of the cell, and thus of the organ and organism. Adaptive responses in metabolism are critical to the recovery at the cellular level. The purpose of these investigations was to test the hypothesis that sepsis is associated with decreased aerobic respiration and significant metabolic changes in the liver.

Methods

C57BL/6 mice underwent cecal ligation and puncture (CLP) with a 21 gauge needle or an operation without CLP. Mice were euthanized from 0–24 h after the procedure and liver tissue was harvested. Tissue oxygen consumption and mitochondrial complex activity were measured. Global biochemical profiles of 311 metabolites were performed at the 8-h time point (n = 8/group) and analyzed by gas chromatography–mass spectrometry and liquid chromatography tandem mass spectrometry platforms by Metabolon (Durham, North Carolina). The influence of lipopolysaccharide (LPS) on aerobic and anaerobic respiration in primary mouse hepatocytes was also investigated.

Results

CLP in vivo or LPS in vitro resulted in a significant decrease in hepatic oxygen consumption. There was a significant decrease in oxidative phosphorylation measured at 12 h. LPS also resulted in a significant increase in anaerobic respiration in hepatocytes. Interestingly, the metabolomic analysis resulted in a metabolic shift in the liver from carbohydrate-based energy to utilization of fatty acids and amino acids. This included an increase in every tricarboxylic acid cycle intermediate and derivative, suggesting an increased flux into the cycle from fatty acid beta-oxidation and anaplerotic contributions from amino acids.

Conclusions

Sepsis results in a metabolic response and profile consistent with increased anaerobic respiration, which occurs prior to significant changes in hemodynamics. The metabolic responses of cells and organs may be important adaptive responses to prevent organ failure and death.