TNFAIP8 modulates the survival and immune activity of Th17 cells via p53/ p21/ MDM2 pathway after acute insult

Tumor necrosis factor-α-induced protein8 (TNFAIP8), which was the first identified member of the TNFAIP8 family, shares considerable sequence homology with other members of the TNFAIP8 family. It is expressed in various normal human tissues, with relatively higher levels detected in lymphoid tissues and the placenta. The present study aimed to examine the effect of TNFAIP8 on cell‑mediated immunity of cluster of differentiation (CD)4+ Tlymphocytes in a cecal ligation and puncture (CLP) murine model. A total of 100male mice were randomly divided into four groups as follows: The sham injury group (n=30), the CLP group (n=30), the CLP with lentivirus‑RNA‑TNFAIP8 group (n=20) and the CLP with negative control group (n=20), and they were sacrificed 24h following CLP. Splenic CD4+ Tcells were isolated using MACS microbeads. Tcell proliferation was analyzed using the MTT assay, and cytokine levels were determined with ELISA kits. Upregulation of TNFAIP8 by lentivirus‑RNA‑TNFAIP8 infection was demonstrated to promote CD4+ T lymphocyte proliferative activity following CLP, and the increase in TNFAIP8 expression invivo affected splenic CD4+ T lymphocyte polarization following CLP‑induced sepsis. In conclusion, TNFAIP8 expression following CLP may be associated with the pathogenesis of immune dysfunction in splenic Tlymphocytes in mice.

Berberine in combination with yohimbine attenuates sepsis-induced neutrophil tissue infiltration and multiorgan dysfunction partly via IL-10-mediated inhibition of CCR2 expression in neutrophils

To investigate the protective effects of Klotho protein, a kind of single-pass transmembrane protein, on acute kidney injury (AKI) in septic mice and its mechanism. Sixty SPF healthy male C57BL/6 mice (6-8 weeks) were randomly divided into sham operation group (Sham group), sepsis model group (CLP group) and Klotho protein injection group (CLP+KL group), with 20 in each group. The septic AKI mice model was established by cecal ligation and puncture (CLP); Sham group had the same procedure except that the cecal was not ligated. The CLP+KL group was received Klotho protein (0.02 mg/kg) by intraperitoneal consecutive injection for 4 days after operation; Sham group and CLP group were injected with the same amount of saline. Blood samples were obtained at 24 hours after operation, the levels of serum creatinine (SCr) and urea nitrogen (BUN) were measured by sarcosine oxidase and urease method. The mice were sacrificed under anesthesia at 5 days after operation to harvest renal tissues, and the pathological damage of the kidney was evaluated by hematoxylin-eosin (HE) staining. The ultrastructure of mitochondria in mouse renal tubular epithelial cells was observed under transmission electron microscope. The levels of reduced glutathione hormone (GSH), malondialdehyde (MDA) and nitric oxide synthase (NOS) in mitochondrion were determined by micro-enzyme method, thiobarbituric acid method, colorimetry method, respectively. The protein expressions of Klotho, Bcl-2 and cytochrome C (Cyt C) were detected by Western Blot. The pathological structure of the kidneys in the Sham group was clear and intact. Compared with the Sham group, the renal tissue edema of the mice in the CLP group was significant, and the transparent tube type was observed in the small lumen, and the interstitial inflammatory cells infiltrated; the levels of SCr and BUN were significantly increased [SCr (μmol/L): 182.60±6.97 vs. 47.20±5.37, BUN (mmol/L): 53.70±5.12 vs. 18.70±2.62, both P < 0.01]; the mitochondria were swollen and deformed, the sputum structure was destroyed, the matrix density was decreased, the outer membrane was lost, and the levels of MDA, GSH and NOS were significantly increased [MDA (μmol/g): 1.172±0.046 vs. 0.746±0.094, GSH (μmol/g): 5.765±0.059 vs. 4.223±0.072, NOS (kU/g): 0.91±0.05 vs. 0.68±0.03, all P < 0.01]; the protein expressions of Klotho and Bcl-2 in renal tissue were decreased, and the protein expression of Cyt C was increased (Klotho/β-actin: 0.188±0.020 vs. 0.538±0.024, Bcl-2/β-actin: 0.311±0.010 vs. 0.391±0.015, Cyt C/β-actin: 0.226±0.010 vs. 0.135±0.006, all P < 0.01). Comparing with the CLP group, the glomerular and tubular tissue epithelial edema and the small lumen in the CLP+KL group were reduced; the levels of SCr and BUN were significantly decreased [SCr (μmol/L): 85.70±7.23 vs. 182.60±6.97, BUN (mmol/L): 35.30±3.50 vs. 53.70±5.12, both P < 0.01]; the mitochondrial structure was relatively intact; the levels of MDA, GSH and NOS were significantly decreased [MDA (μmol/g): 0.958±0.072 vs. 1.172±0.046, GSH (μmol/g): 4.756±0.107 vs. 5.765±0.059, NOS (kU/g): 0.79±0.02 vs. 0.91±0.05, all P < 0.01]; the protein expressions of Klotho, Bcl-2 were significantly increased, but the protein expression of Cyt C was significantly decreased (Klotho/β-actin: 0.336±0.011 vs. 0.188±0.020, Bcl-2/β-actin: 0.474±0.017 vs. 0.311±0.010, Cyt C/β-actin: 0.168±0.006 vs. 0.226±0.010, all P < 0.01). Klotho protein has significant protective effects on AKI in septic mice, and its mechanism is related to maintaining mitochondrial structural integrity and oxidative stress response.

Objective To investigate the protective effects of hydrogen gas (H2) inhalation on acute renal injury in severe septic mice,and the associated mechanism.Methods Sepsis model was made by cecal ligation and puncture (CLP) operation in mice.A total of 24 mice were randomly (random number)divided into four groups:sham operation group (Sham),sham operation with H2 inhalation group (Sham +H2),sepsis group (Sepsis),and sepsis with H2 inhalation group (Sepsis + H2).The procedure for inhalation of 2％ H2 for 1 h was initiated at 1 h after CLP and 6 h after sham operation,respectively.The pathological changes and apoptosis of kidney,the blood creatinine (Cr) and blood urea nitrogen (BUN)concentration,the activities of superoxide dimutase (SOD) and catalase (CAT) in serum and kidney,as well as the levels of 8-iso-prostaglandin F2α (8-iso-PGF2α) and high mobility group box 1 (HMGB1) in serum and kidney were observed at 24 h after operation.Results H2 inhalation could significantly alleviate the renal injury of septic mice,reduce the renal cell apoptosis,increase the activities of SOD and CAT,as well as decrease the levels of 8-iso-PGF2α and HMGB1 in serum and kidney (P ＜ 0.05).Conclusions H2 inhalation can alleviate acute renal injury in septic mice,resulting from the increased activities of antioxidant enzymes and the reduced levels of oxidative products and inflammatory cytokines. Key words: Hydrogen ; Sepsis ; Acute renal injury ; Antioxidant enzyme ; Inflammatory cytokine

To explore the protective effect of placenta-derived mesenchymal stem cells (P-MSCs) transplantation on intestinal injury in septic mice and its mechanism. A total of 24 mice were randomly assigned to 3 groups, a sham operation group, a sepsis group that underwent cecal ligation and puncture (CLP) procedure, and a group that received CLP and P-MSCs treatment. Hereinafter, the three groups are referred to as the Sham group, the CLP group, and the CLP+P-MSCs group. For the mice in the Sham group, the abdomen was cut open and the cecum was exposed and then placed back in the abdomen. CLP was performed in the other two groups to establish the sepsis model. Mice in the Sham and the CLP groups received 0.1 mL of 0.9% NaCl injection in the tail vein 1 hour after operation, while mice in the CLP+P-MSCs group received 2×10 5 P-MSCs infusion 1 hour after operation. Intestinal and blood specimens were collected from the mice in each group 24 hours after P-MSCs transplantation. Hematoxylin and eosin (HE) staining of the intestinal tissue was performed for pathological evaluation. The serum concentrations of D-lactic acid, diamine oxidase (DAO), endotoxin, interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, IL-10, and transforming growth factor (TGF)-β were determined by enzyme linked immunosorbent assay (ELISA). The gene expression of the relevant inflammatory factors in the small intestinal tissue was determined by real-time fluorescence polymerase chain reaction. The expression of zonula occludens protein-1 (ZO-1) and occludin protein in the intestine was determined by Western blot, the infiltration of intestinal macrophages was determined by immunohistochemical method, and the polarization of macrophages was determined by immunofluorescence. The exogenous transplantation of P-MSCs could form colonies in the injured intestines of septic mice. Compared with those of the CLP group, the intestinal injury of the CLP+P-MSCs group was significantly alleviated, the serum concentrations of D-lactic acid, DAO, endotoxin, IL-1β, IL-6, and TNF-α were significantly decreased ( P<0.05), while the serum concentrations of IL-10 and TGF-β were significantly increased ( P<0.05), the expression levels of IL-1 β, TNF-α and IL-6 genes in the intestinal tissue were significantly decreased ( P<0.05), while the expression levels of IL-10 and TGF-β genes were significantly increased ( P<0.05), and the expression of ZO-1 and occludin proteins in the intestine was also significantly increased ( P<0.05). In addition, the distribution of macrophages in the intestinal tissue of the CLP+P-MSCs group decreased significantly and the macrophages showed a tendency for M2 polarization. Exogenous transplantation of P-MSCs can significantly reduce inflammatory injury and improve the intestinal barrier function in septic mice with intestinal injury. Reduction in the infiltration of macrophages and promotion of the polarization of macrophages from M1 to M2 may be the mechanisms underlying the reduction of inflammation.

PurposeA common complication of sepsis is acute lung injury (ALI), which is associated with an acute onset, rapid disease changes, and high mortality. Regulatory T (Treg) and T helper 17 (Th17) cells comprise CD4+ T cell subsets, which strongly influence inflammation during ALI. In this study, we investigated the effect of berberine (BBR), an antioxidant, anti-inflammatory, and immunomodulatory drug, on the inflammatory response and immune state in mice with sepsis.MethodsA mouse model of cecal ligation and puncture (CLP) was established. The mice were intragastrically administered 50 mg/kg BBR. We used histological techniques to evaluate inflammatory tissue injury and flow cytometry for analyzing Treg/Th17 levels. We also assessed NF-κB signaling pathways by Western blotting assays and immunofluorescence staining. Enzyme-linked immunosorbent assay (ELISA) was performed to measure the content of cytokines.ResultsTreatment with BBR considerably mitigated lung injury while improving survival, post-cecal ligation, and puncture (CLP). Treatment with BBR ameliorated pulmonary edema and hypoxemia in septic mice and inhibited the NF-κB signaling pathway. BBR also increased Treg cells and decreased Th17 proportions in the spleen and lung tissue of CLP-treated mice. Blocking Treg cells weakened the protective effect of BBR on sepsis-associated lung injury.ConclusionOverall, these results suggested that BBR is a potential therapeutic agent for sepsis.

To investigate the effect of deletion of small ubiquitin-like modifier (SUMO) on the function of dendritic cells (DC) in septic mice and its role in sepsis. Septic models of DC-specific ubiquitin-conjugating enzyme 9 (UBC9) deficient (UBC9ΔDC) mice and wild type (WT) mice with cecal ligation and puncture (CLP) were established. The differences in 7-day mortality of the mice were analyzed. Bacteria loads of blood, liver, and spleen were tested. ELISA was used to detect the levels of IL-1β, IL-6, IL-18, and TNF-α in plasma and culture medium of bone marrow-derived dendritic cells (BMDC). The levels of cytokine IFN-γ and IL-4 in supernatant of spleen mononuclear cells were detected by ELISA.The expressions of MHC II, CD54, and CD80 on the cell surface of DC were analyzed by flow cytometry. The percentages of Th1, and Th2 cells in spleen mononuclear cells were analyzed by flow cytometry. Compared with the WT septic mice, the 7-day mortality of UBC9ΔDC septic mice was higher (P<0.05). Bacterial loads in blood (P<0.01), liver (P<0.01), and spleen (P<0.05) were significantly increased in UBC9ΔDC septic mice. Levels of IL-1β and IL-18 in plasma and culture supernatant of BMDC were also significantly increased in UBC9ΔDC septic mice (all P<0.01). There was no significant difference in the number of DC and the expression of cell surface molecules in DC of UBC9ΔDC septic mice (all P>0.05).The percentage of Th2 cells was significantly increased in UBC9ΔDC septic mice (P<0.05). The ratio of Th1 to Th2 was decreased in UBC9ΔDC septic mice but the difference was not significant (P>0.05). Levels of IFN-γ and IL-4 were increased in UBC9ΔDC septic mice, and the ratio of IFN-γ to IL-4 were significantly decreased in UBC9ΔDC septic mice (all P<0.05). Deletion of SUMOylation may increase the mortality of mice with sepsis through regulating the release of inflammatory factors from DC and abnormal activation of T cells by DC.

This study was designed to investigate the protective effect and mechanism of Sufentanil on acute lung injury in septic mice based on network pharmacology and animal experiments, and to provide new ideas for clinical treatment. To this end, a protein-protein interaction (PPI) network for common targets was first constructed with Swiss Target Prediction Database, GeneCards Database, Draw Venn Diagram Software, STRING 11.5 Database, Cytoscape 3.10.0 Software and Metascape Database, and then key targets were subject to enrichment analysis by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) to obtain the key targets of Sufentanil for the treatment of pulmonary sepsis, and then verified by animal experiments. A sepsis model was constructed by cecal ligation and puncture (CLP) in this study, and lung tissues and bronchoalveolar lavage fluid (BALF) were taken from each group of mice. The morphological changes of lung tissues and apoptosis were observed by HE and TUNEL staining, the content of inflammatory factors in the lung tissues was detected by ELISA, and the expression of proteins, such as p-JAK2 and p-STAT3, was detected in the lung tissues by Western blotting. According to the results of network pharmacology, a total of 40 common targets of were screened out for Sufentanil and pulmonary sepsis, and GO enrichment analysis involved 1,483 biological processes (BPs), 84 cellular components (CCs) and 125 molecular functions (MFs); KEGG enrichment analysis identified 137 signaling pathways with p < 0.05 such as JAK-STAT. According to the results of animal experiments, compared with the control group, mice in the model group had severe lung tissue injury and elevated expression of relevant inflammatory factors in lung tissue. Compared with the model group, CLP + Sufentanil group showed reduced pathomorphologic lesions, lower expression of inflammatory factors and apoptosis level, as well as lower expression of p-JAK2 and p-STAT3 proteins in lung tissue. The results of animal experiments were consistent with network pharmacology. In summary, Sufentanil may improve lung injury in septic mice by inhibiting the JAK2-STAT3 signaling pathway, which provides a basis for research on the mechanism of Sufentanil on pulmonary sepsis and clinical treatment.

To observe the ferroptosis triggered by in different pathways during cecal ligation and puncture (CLP)-induced liver injury in septic mice, and to investigate whether mitochondrial aldehyde dehydrogenase 2 (ALDH2) can alleviate sepsis-induced liver injury by inhibiting ferroptosis. Sixty 8-week-old male C57BL/6J mice were randomly divided into sham operation group (Sham group), CLP group, ferroptosis inhibitor ferrostain-1 (Fer-1) group, ALDH2-specific agonist Alda-1 group, iron chelator deferasirox Fe3+ chelate (DXZ) group and dimethyl sulfoxide (DMSO) group, with 10 mice in each group. The septic liver injury was induced by CLP in mice model. In the Sham group, only laparotomy was performed without ligation and puncture of the cecum. 10 mL/kg 5% DMSO, 5 mg/kg Fer-1, 50 mg/kg DXZ and 10 mg/kg Alda-1 were injected intraperitoneally 1 hour before CLP in the DMSO, Fer-1, DXZ and Alda-1 groups respectively. At 24 hours after operation, eyeball blood and liver tissue were collected from anesthetized mice. The hepatic structure and inflammatory infiltration were observed by hematoxylin-eosin (HE) staining. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) in serum, the levels of hepatic malondialdehyde (MDA), superoxide dismutase (SOD) and reactive oxygen species (ROS) were detected. Western blotting was used to detect the protein expressions of ALDH2, ferroptosis-related proteins glutathione peroxidase 4 (GPX4), ferroptosis suppressor protein 1 (FSP1) and transferrin receptor 1 (TFR1) in liver tissue. Compared with Sham group, the mice in CLP group showed varying degrees of congestion, disorganized hepatocyte arrangement, inflammatory cell infiltration at 24 hours after operation. Compared with the CLP group, the mice in the Fer-1 group, DXZ group and Alda-1 group liver morphology, liver injury and inflammatory cell infiltration was improved. Compared with Sham group, the serum levels of ALT and AST, the contents of MDA and ROS, and the expression of TFR1 protein in CLP group were significantly increased, while the activity of SOD and the expressions of ALDH2, GPX4 and FSP1 protein in CLP group were significantly decreased. Compared with CLP group, serum ALT and AST levels in Fer-1, DXZ and Alda-1 groups were significantly decreased [ALT (U/L): 45.76±10.81, 37.30±2.98, 36.40±12.75 vs. 73.06±12.20, AST (U/L): 61.57±2.69, 52.41±6.92, 56.05±8.29 vs. 81.59±5.46, all P < 0.05], and the contents of MDA, ROS and TFR1 protein expression in liver tissue were significantly decreased [MDA (μmol/L): 0.60±0.10, 0.57±0.18, 0.83±0.39 vs. 1.61±0.30, ROS (fluorescence intensity): 270.34±9.64, 276.02±62.33, 262.05±18.55 vs. 455.38±36.07, TFR1/GAPDH: 0.90±0.04, 1.01±0.09, 0.55±0.08 vs. 1.18±0.06, all P < 0.05], and the SOD activity and ALDH2, GPX4 and FSP1 protein expressions in liver tissue were significantly increased [SOD (kU/g): 88.77±8.20, 88.37±4.47, 93.43±7.24 vs. 50.27±3.57, ALDH2/GAPDH: 1.10±0.15, 1.02±0.07, 1.14±0.07 vs. 0.70±0.04, GPX4/GAPDH: 1.02±0.12, 0.99±0.08, 1.05±0.19 vs. 0.71±0.10, FSP1/GAPDH: 1.06±0.24, 1.02±0.08, 0.93±0.09 vs. 0.66±0.03, all P < 0.05]. There was no significant difference in the parameters between DMSO group and CLP group. Both GPX4 and FSP1 mediated ferroptosis are involved in liver injury in septic mice. Activation of ALDH2 and inhibition of ferroptosis can alleviatehepatic injury. ALDH2 may play a protective role by regulating FSP1 and GPX4 mediated ferroptosis.

TH2 heterogeneity: Does function follow form?

Background: Sepsis is a life-threatening clinical condition often seen in intensive care units, leading to multi-organ dysfunction. Myocardial injury is a prevalent complication, significantly increasing mortality among sepsis patients. Although heparin is used in sepsis management, its specific effects on myocardial injury and the role of neutrophil extracellular traps (NETs) in this context remain insufficiently understood. Aim: This study investigates the role of unfractionated heparin (UFH) combined with DNase I in reducing myocardial injury in a septic mouse model. Methods: A cecal ligation and puncture (CLP)-induced sepsis model was established in C57BL/6 mice to study myocardial injury. The experimental groups included treatments with UFH, UFH with DNase I, and NETs introduction. Myocardial injury was assessed using hematoxylin and eosin staining, enzyme linked immunosorbent assay for injury markers (creatine kinase MB [CK-MB] and lactate dehydrogenase [LDH]), and Western blotting for inflammatory proteins (TNF-α and IL-6). Differential proteomic analysis using data independent acquisition mass spectrometry and pathway enrichment analysis (Gene Ontology and Kyoto Encyclopedia of Genes and Genomes) were conducted to identify molecular pathways and key proteins affected by the treatments. Results: Single UFH treatment increased the formation of NETs, upregulated TNF-α and IL-6, and increased CK-MB and LDH, worsening myocardial injury. The combination of UFH and DNase I significantly reduced myocardial injury, suppressing NETs formation and inflammation. Proteomic analysis identified crucial pathways related to NETs, metabolism, and complement and coagulation cascades, with proteins Ccn1 and Tagln highlighted as potential therapeutic targets. Conclusion: UFH combined with DNase I effectively alleviates myocardial injury in septic mice by modulating NETs formation and associated inflammatory processes. This study may provide new insights and options for the early use of heparin in the treatment of septic patients, particularly in cases with a higher risk of myocardial injury.

During sepsis, systemic inflammation is observed and is associated with multiple organ failure. Activation of NF-κB is crucial for inducing inflammation, which is controlled by degradation of inhibitor molecules (IκB). The ubiquitination proteasome pathway is responsible for the regulation of protein turnover. In this study, we hypothesized that administration of 4[4-(5-nitro-furan-2-ylmethylene)-3, -dioxo-pyrazolidin-1-yl]-benzoic acid ethyl ester (PYR-41), an inhibitor of ubiquitination, could reduce inflammation and organ injury in septic mice. PYR-41 prevented the reduction of IκB protein levels and inhibited release of tumor necrosis factor (TNF)-α in mouse macrophage RAW264.7 cells at 4 h after lipopolysaccharide stimulation dose-dependently. Male C57BL/6 mice were subjected to cecal ligation and puncture (CLP) to induce sepsis. PYR-41 (5 mg/kg) or dimethyl sulfoxide in saline (vehicle) was injected intravenously immediately after CLP. At 20 h after CLP, PYR-41 treatment significantly decreased serum levels of proinflammatory cytokines (TNF-α, interleukin [IL]-1β, and IL-6) and organ injury markers (aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase). PYR-41 significantly improved microscopic structure, and reduced myeloperoxidase activity, number of apoptotic cells and caspase-3 degradation in the lungs of septic mice. The reduced protein levels of IκB in the lungs after CLP were restored by PYR-41 treatment. PYR-41 inhibited the expression of cytokines (IL-1β and IL-6), chemokines (keratinocyte-derived chemokine and macrophage inflammatory protein 2), and inflammatory mediators (cyclooxygenase-2 and inducible nitric oxide synthase) in the lungs of septic mice. Importantly, PYR-41 significantly increased 10-day survival in septic mice from 42% to 83%. Therefore, targeting ubiquitination by PYR-41 to inhibit NF-κB activation may represent a potential strategy of sepsis therapeutics.

To investigate the mechanism of tea polyphenols (TP) for regulating NLRP3 inflammasomes and alleviating acute lung injury in septic mice. Sixty C57BL/6 mice were randomly assigned into sham-operated, cecal ligation and puncture (CLP) and CLP +TP treatment groups, and survival of the mice was recorded after modeling in each group. The lung wet/dry weight ratio and myeloperoxidase (MPO) activity were determined, and lung injury of the mice was evaluated using HE staining and acute lung injury score. The expressions of IL-1β, TNF-α, IL-6, NLRP3, caspase-1 p10, ASC, MPO, and caspase-8 in the lung tissue were detected using ELISA, Western blotting, or immunohistochemical staining. MDA and H2O2 levels in the lungs were detected to evaluate the level of oxidative stress. Immunofluorescence assay was used to investigate the co-localization of NLRP3 and NOX4. The postoperative mortality rate at 72 h, lung wet/dry weight ratio, MPO level and acute lung injury scores were significantly lower in CLP+TP group than in CLP group (P < 0.05). Treatment with TP significantly reduced the expressions of NLRP3-related inflammatory factors (P < 0.05) and lowered MDA and H2O2 levels in the lung tissue of the septic mice (P < 0.05). Immunofluorescence co-staining showed a lower level of NOX4 and NLRP3 co-localization in CLP+TP group than in CLP group. TP inhibits NLRP3 inflammasome-associated inflammation to alleviate CLP-induced acute lung injury in mice through a regulatory mechanism that inhibits NOX4 expression and reduces oxidative stress in the lung tissue.

Objective: To explore the expression and roles of nucleolin in cardiac injury in septic mice. Methods: C57BL/6 mice (WT mice) and myocardium-specific expression of nucleolin transgenic mice (TG mice) were randomly divided into sham group (n=10, sham-operated) and sepsis group (n=15, animal model). Cecal ligation and puncture (CLP) was adopted to produce animal models of sepsis. The expression of nucleolin was detected by Western blotting analysis at 0, 12, 24, 48 hours after the operation. The 7-day survival rate, haemodynamic measurement, levels of isoenzyme of creatinekinase-MB (CK-MB) and cardiac troponin I (cTnI) in serum and levels of reactive oxygen species (ROS) and malondlaldehyde (MDA) in myocardium were evaluated 24 hours after the operation. The data were compared between groups with t test. Results: The expression of nucleolin in myocardium up-regulated significantly in WT+CLP group when compared with that in the WT+Sham group(2.57±0.34 vs 1.00±0.15, t=7.468, P<0.01). Compared with those in the WT+Sham group, the survival rate decreased (33.3% vs 100%, χ(2)=13.375, P<0.01), maximal rate of pressure development (+dp/dtmax) declined (t=4.993, P<0.01), but the serum levels of CK-MB and cTnI and the levels of ROS and MDA in myocardium increased in the WT+CLP group(t=5.031, 4.335, 3.365, 2.375, all P<0.05). Compared with that in WT+CLP group, the 7-day survival rate of mice increased in TG+CLP group (60.0% vs 33.3%, χ(2)=8.227, P=0.004), and the cardiac function improved (t=2.337, P=0.019), but the serum levels of CK-MB and cTnI and the levels of ROS and MDA in myocardium in TG+CLP group reduced significantly (t=2.127, 3.347, 2.115, 2.224,P<0.05). Conclusion: The expression of nucleolin is up-regulated in the myocardium of septic mice, and the overexpression of nucleolin can inhibit oxidative stress injury, attenuate the cardiac injury and dysfunction, and reduce mortality in septic mice.

Mechanical ventilation (MV) is frequently employed to manage respiratory failure in sepsis patients and is required for the surgical management of intra-abdominal sepsis. The impact of MV varies dramatically depending on tidal volume, with even moderate tidal volume (MTV) ventilation leading to ventilator-induced lung injury, whereas low tidal volume (LTV) ventilation protects against sepsis-induced acute respiratory distress syndrome. Interleukin (IL)-33 is known to contribute to lung injury in sepsis and its release can be induced by mechanical stress. To determine the relationship between the IL-33-suppression of tumorigenicity 2 (ST2) pathway and patterns of lung injury associated with MV in sepsis, mice were subjected to cecal ligation and puncture (CLP) followed 6 h later by either MTV (10 mL/kg) or LTV (6 mL/kg) ventilation for 4 h. MTV and LTV ventilation alone for 4 h had no impact on lung injury. MTV markedly exacerbated lung injury and inflammation, while LTV significantly suppressed these parameters in septic mice. Lung and plasma levels of IL-33 ST2 were significantly elevated by CLP alone at 10 h. MTV caused further and significant increases in IL-33 and sST2 levels, while LTV significantly suppressed levels induced by CLP. Deletion of IL-33 or ST2 prevented the increase in lung injury and inflammation induced by MTV in septic mice, while administration of recombinant IL-33 in the airway reversed the protection seen with LTV. Taken together, these findings implicate the IL-33-ST2 pathway in the pro-inflammatory changes induced by the mechanical ventilation that leads to lung injury in the setting of intra-abdominal sepsis in a tidal volume-dependent manner.