Combining ulinastatin with TIENAM improves the outcome of sepsis induced by cecal ligation and puncture in mice by reducing inflammation and regulating immune responses.

Despite the high mortality associated with sepsis, effective and targeted treatments remain scarce. The use of conventional antibiotics such as TIENAM (imipenem and cilastatin sodium for injection, TIE) is challenging because of the increasing bacterial resistance, which diminishes their efficacy and leads to adverse effects. Our previous studies demonstrated that ulinastatin (UTI) exerts a therapeutic impact on sepsis by reducing systemic inflammation and modulating immune responses. In this study, we examined the possibility of administering UTI and TIE after inducing sepsis in a mouse model using cecal ligation and puncture (CLP). We assessed the rates of survival, levels of inflammatory cytokines, the extent of tissue damage, populations of immune cells, microbiota in ascites, and important signaling pathways. The combination of UTI and TIE significantly improved survival rates and reduced inflammation and bacterial load in septic mice, indicating potent antimicrobial properties. Notably, the survival rates of UTI+TIE-treated mice increased from 10 % to 75 % within 168 h compared to those of mice that were subjected to CLP. The dual treatment successfully regulated the levels of inflammatory indicators (interleukin [IL]-6, IL-1ß, and tumor necrosis factor [TNF]-α) and immune cell numbers by reducing B cells, natural killer cells, and TNFR2+ Treg cells and increasing CD8+ T cells. Additionally, the combination of UTI and TIE alleviated tissue damage, reduced bacterial load in the peritoneal cavity, and suppressed the NF-κB signaling pathway. Our findings indicate that UTI and TIE combination therapy can significantly enhance sepsis outcomes by reducing inflammation and boosting the immune system. The results offer a promising therapeutic approach for future sepsis treatment.

The Dual Role of Neutrophil Extracellular Traps (NETs) in Sepsis and Ischemia-Reperfusion Injury: Comparative Analysis across Murine Models.

A better understanding of the function of neutrophil extracellular traps (NETs) may facilitate the development of interventions for sepsis. The study aims to investigate the formation and degradation of NETs in three murine sepsis models and to analyze the production of reactive oxygen species (ROS) during NET formation. Murine sepsis was induced by midgut volvulus (720° for 15 min), cecal ligation and puncture (CLP), or the application of lipopolysaccharide (LPS) (10 mg/kg body weight i.p.). NET formation and degradation was modulated using mice that were genetically deficient for peptidyl arginine deiminase-4 (PAD4-KO) or DNase1 and 1L3 (DNase1/1L3-DKO). After 48 h, mice were killed. Plasma levels of circulating free DNA (cfDNA) and neutrophil elastase (NE) were quantified to assess NET formation and degradation. Plasma deoxyribonuclease1 (DNase1) protein levels, as well as tissue malondialdehyde (MDA) activity and glutathione peroxidase (GPx) activity, were quantified. DNase1 and DNase1L3 in liver, intestine, spleen, and lung tissues were assessed. The applied sepsis models resulted in a simultaneous increase in NET formation and oxidative stress. NET formation and survival differed in the three models. In contrast to LPS and Volvulus, CLP-induced sepsis showed a decreased and increased 48 h survival in PAD4-KO and DNase1/1L3-DKO mice, when compared to WT mice, respectively. PAD4-KO mice showed decreased formation of NETs and ROS, while DNase1/1L3-DKO mice with impaired NET degradation accumulated ROS and chronicled the septic state. The findings indicate a dual role for NET formation and degradation in sepsis and ischemia-reperfusion (I/R) injury: NETs seem to exhibit a protective capacity in certain sepsis paradigms (CLP model), whereas, collectively, they seem to contribute adversely to scenarios where sepsis is combined with ischemia-reperfusion (volvulus).

Maresin1 prevents sepsis-induced acute liver injury by suppressing NF-κB/Stat3/MAPK pathways, mitigating inflammation.

Aims: The treatment of sepsis remains challenging and the liver is a non-neglectful target of sepsis-induced injury. Uncontrolled inflammatory responses exert a central role in the pathophysiological process of sepsis-induced acute liver injury (SI-ALI). Maresin1 (MaR1) is a derivative of omega-3 docosahexaenoic acid (DHA), which has been shown to have anti-inflammatory effects and is effective in a variety of sepsis-related diseases. This study aimed to determine the effect of MaR1 on cecal ligation and puncture (CLP)-caused SI-ALI and explore its possible mechanisms. Main methods: Mice were subjected to CLP, and then intravenously injected via tail vein with low-dose MaR1 (0.5 ng, 200 µL) or high-dose MaR1 (1 ng, 200 µL) or sterile normal saline (NS) (200 µL) 1 h later. Then, the survival rate, body weight change, liver function, bacterial load, neutrophil infiltration, and inflammatory cytokines were detected. Results: MaR1 significantly increased the 7-day survival rate and reduced the bacterial load in peritoneal lavage fluid and blood in a dose-dependent manner in mice with SI-ALI. Treatment with MaR1 could also restore the function of the liver in septic mice. Besides, MaR1 exerted anti-inflammatory effects by decreasing the expression of pro-inflammatory molecules (TNF-α, IL-6 and IL-1ß), bacterial load, and neutrophil infiltration and increasing the expression of anti-inflammatory molecules (IL-10). Significance: Our experimental results showed that MaR1 alleviated liver injury induced by sepsis. This work highlighted a potential clinic use of MaR1 in treating acute inflammation of SI-ALI, but also provided new insight into the underlying molecular mechanism.

DLK1 overexpression improves sepsis-induced cardiac dysfunction and fibrosis in mice through the TGF-ß1/Smad3 signaling pathway and MMPs.

Sepsis is a serious inflammatory disease caused by bacterial infection. Cardiovascular dysfunction and remodeling are serious complications of sepsis, which can significantly affect sepsis patients' mortality. Delta-like homologue 1 (DLK1) has been reported could inhibit cardiac myofibroblast differentiation. However, the function of DLK1 in sepsis is unknown. In the present study, the DLK1 expression was first identified based on the online dataset GSE79962 analysis and cecal ligation and puncture (CLP)-induced sepsis mouse model. DLK1 expression was significantly reduced in septic heart tissues. In septic mouse heart, CLP operation decreased the fractional shortening (EF) (%) and ejection fraction (FS) (%) and caused significant edema, disordered myofilament arrangement, and degradation and necrosis in myocardial cells; CLP operation also increased collagen deposition and elevated the protein levels of fibrotic markers (α-SMA and F-actin). DLK1 overexpression in septic mice could effectively increase EF (%) and FS (%), attenuate CLP-caused ECM degradation and deposition and partially inhibit the CLP-induced TGF-ß1/Smad signaling activation. In conclusion, DLK1 expression was poorly expressed in the CLP-induced septic mouse heart. DLK1 overexpression partially alleviated sepsis-induced cardiac dysfunction and fibrosis, with the involvement of the TGF-ß1/Smad3 signaling pathway and MMPs.

Early treatment with C-reactive protein-derived peptide reduces septic acute kidney injury in mice via controlled activation of kidney macrophages.

The mortality rate for acute kidney injury (AKI) due to sepsis remains high, and effective therapies based on its pathogenesis remain elusive. Macrophages are crucial for clearing bacteria from vital organs, including the kidney, under septic conditions. Excessive macrophage activation results in organ injury. C-reactive protein (CRP) peptide (174-185), a functional product of proteolyzed CRP in vivo, effectively activates macrophages. We investigated the therapeutic efficacy of synthetic CRP peptide on septic AKI, focusing on effects on kidney macrophages. Mice underwent cecal ligation and puncture (CLP) to induce septic AKI and were intraperitoneally administered 20 mg/kg of synthetic CRP peptide 1 h post-CLP. Early CRP peptide treatment improved AKI while still clearing infection. Ly6C-negative kidney tissue-resident macrophages did not significantly increase at 3 h after CLP, while Ly6C-positive monocyte-derived macrophages significantly accumulated in the kidney 3 h post-CLP. CRP peptide augmented the phagocytic ROS production in both subtypes of kidney macrophage at 3 h. Interestingly, both subtypes of macrophage increased ROS production 24 h post-CLP compared to the control group, while CRP peptide treatment maintained ROS production at the same level seen 3 h post-CLP. Although bacterium-phagocytic kidney macrophages produced TNF-α, CRP peptide reduced bacterial propagation and tissue TNF-α levels in the septic kidney at 24 h. Although both subsets of kidney macrophages showed populations of M1 at 24 h post-CLP, CRP peptide therapy skewed the macrophages population toward M2 at 24 h. CRP peptide alleviated murine septic AKI via the controlled activation of kidney macrophages and is an excellent candidate for future human therapeutic studies.

Disrupted metabolic and spontaneous neuronal activity of hippocampus in sepsis associated encephalopathy rats: A study combining magnetic resonance spectroscopy and resting-state functional magnetic resonance imaging.

Background: The diagnosis of sepsis associated encephalopathy (SAE) remains challenging in clinical settings because of a lack of specific biomarkers. Functional magnetic resonance imaging (fMRI) and proton magnetic resonance spectroscopy (1H-MRS) can be used to aid in the diagnosis of cognition related diseases. This study investigated changes in functional activities and brain metabolites in the hippocampus in SAE rats by fMRI and 1H-MRS. Materials and methods: Sepsis associated encephalopathy rats underwent cecal ligation and perforation (CLP) surgery. The Morris water maze (MWM) test was then used to evaluate cognitive function. Resting state-fMRI and 1H-MRS scanning were performed 7 and 14 days after CLP surgery to reveal spontaneous neuronal activity and metabolite changes in the hippocampus. The amplitude of low-frequency fluctuation (ALFF) was used to evaluate spontaneous neuronal activity in the hippocampus. Creatine (Cr), Myo-inositol (mI), and glutamine/glutamate (Glx) levels were measured with 1H-MRS scanning. Immunofluorescence and levels of interleukin (IL)-1ß, interleukin (IL)-6, and C-reactive protein (CRP) in the hippocampus were additionally detected to evaluate microglial mediated inflammatory responses. Statistical analysis was performed to evaluate correlations between hippocampal metabolism and behavioral findings. Results: Cecal ligation and perforation treated rats exhibited impaired learning and memory function in the MWM test at days 7 and 14. Elevation of IL-1ß in the hippocampus, as well as immunofluorescence results, confirmed severe neuro inflammation in the hippocampus in SAE rats. Compared with the sham group, the ALFF of the right CA-1 area of the hippocampus was higher at day 7after CLP surgery. The Glx/Cr and mI/Cr ratios were enhanced at day 7 after CLP surgery and slightly lower at day 14 after CLP surgery. The ALFF value, and Glx/Cr and mI/Cr ratios were negatively correlated with time spent in the target quadrant in the MWM test. Conclusion: Spontaneous neuronal activity and metabolites showed significant alterations in SAE rats. The elevated ALFF value, Glx/Cr ratio, and mI/Cr ratio in the hippocampus were positively associated with cognitive deficits. Changes in ALFF and metabolites in hippocampus may serve as potential neuroimaging biomarkers of cognitive disorders in patients with SAE.

Short Chain Fatty Acids Protect the Cognitive Function of Sepsis Associated Encephalopathy Mice via GPR43.

Objective: This study aims to analyze the changes of fecal short chain fatty acids (SCFAs) content and gut microbiota composition in sepsis associated encephalopathy (SAE) mice, further evaluating the effect of SCFAs on cognitive function and the underlying mechanism in SAE mice. Methods: A total of 55 male adult C57BL/6 mice (2-3 months of age, 20-25 g) were divided into four groups randomly: sham group (n = 10), cecal ligation and puncture group (CLP group, n = 15), CLP+SCFAs group (n = 15), and CLP+SCFAs+GLPG0974 group (n = 15). Seven days after surgery, fecal samples were collected for microbiota composition and SCFA analysis from 6 mice in each group randomly. Behavioral test was applied to assess cognitive impairment at the same time. After that, mice were sacrificed and brain tissue was harvested for inflammatory cytokines analysis. Results: The levels of acetic acid (.57 ± 0.09 vs 2.00 ± 0.24, p < 0.001) and propionic acid (.32 ± 0.06 vs .66 ± 0.12, p = 0.002) were significantly decreased in the CLP group compared with the sham group. The administration of SCFAs significantly increased the levels of acetic acid (1.51 ± 0.12 vs. 0.57 ± 0.09, p < 0.001) and propionic acid (0.54 ± 0.03 vs. 0.32 ± 0.06, p = 0.033) in CLP+SCFAs group compared with CLP group. Relative abundance of SCFAs-producing bacteria, including Allobaculum (0.16 ± 0.14 vs. 15.21 ± 8.12, p = 0.037), Bacteroides (1.82 ± 0.38 vs. 15.21 ± 5.95, p = 0.002) and Bifidobacterium (0.16 ± 0.06 vs. 2.24 ± 0.48, p = 0.002), significantly decreased in the CLP group compared with the sham group. The behavioral tests suggested that cognitive function was impaired in SAE mice, which could be alleviated by SCFAs pretreatment. ELISA tests indicated that the levels of IL-1ß, IL-6, and TNF-α were elevated in SAE mice and SCFAs could lower them. However, the GPR43 antagonist, GLPG0974, could reverse the cognitive protective effect and anti-neuroinflammation effect of SCFAs. Conclusion: Our study suggested that in SAE, the levels of acetate and propionate decreased significantly, accompanied by gut microbiota dysbiosis, particularly a decrease in SCFAs-producing bacteria. GPR43 was essential for the anti-neuroinflammation and cognitive protective effect of SCFAs in SAE.

Circular RNA mmu_circ_0001295 from hypoxia pretreated adipose-derived mesenchymal stem cells (ADSCs) exosomes improves outcomes and inhibits sepsis-induced renal injury in a mouse model of sepsis.

Microvascular dysfunction causes mortality in the presence of sepsis and multi-organ failure. Previous studies have demonstrated that exogenous administration of exosomes from adipose-derived mesenchymal stem cells (ADSCs) protects against sepsis, improves organ function, decreases vascular leakage and increases survival. However, the underlying regulatory mechanism was largely unknown. Therefore, in this study, a mouse sepsis model based on cecal ligation and puncture (CLP) was constructed. Exosomes from various ADSCs were intravenously administered at 4 h post CLP. Treatment with ADSC exosomes (Exo), particularly those with hypoxic pretreatment (HExo), enhanced survival, suppressed renal vascular leakage and decreased kidney dysfunction in septic mice. HExo ameliorated sepsis-induced increases in chemokine and cytokine plasma levels. Furthermore, the HExo circRNA content, determined through next-generation sequencing, revealed abundant mmu_circ_0001295. Further studies demonstrated that downregulation of exosomal mmu_circ_0001295 suppressed the exosomes' protective effects against sepsis. HExo prevented microvascular dysfunction, thus potentially improving sepsis outcomes via mmu_circ_0001295 delivery. In summary, the data indicated that HExo elongate sepsis-induced renal injury through delivering mmu_circ_0001295.

OGDH is involved in sepsis induced acute lung injury through the MAPK pathway.

BACKGROUND: Acute lung injury (ALI) induced by sepsis is a common cause of death in clinical practice, and there remains a lack of clinical effective treatment. Cecal ligation and puncture (CLP) is a classic animal model of sepsis, which can induce ALI. Studies have shown that in the lung injury cell model, OGDH (oxoglutarate dehydrogenase) transcription is up-regulated, which is a potential therapeutic target for acute pneumonia. The purpose of this study was to confirm the effects of OGDH on lung injury and inflammation in animal and cell models, and to explore its mechanism. METHODS: By analyzing the GSE16650 gene set, the upregulated OGDH gene was detected in the lung injury cell model. In a sepsis animal model established by CLP and a lung injury cell model, RT-PCR, immunohistochemistry, WB, and other techniques were used to verify the upregulation of OGDH expression, which was then was down-regulated with shRNA to confirm its relationship with ALI. Further, ELISA, RT-PCR, and WB were used to detect the effect of OGDH on the expression of pro-inflammatory factors including IL-1ß, IL-6, IL-18, and TNF-α. The downstream pathway of OGDH was predicted using KEGG and GSEA tools and verified by WB and immunofluorescence. RESULTS: The results showed OGDH was highly expressed in a lung injury cell model and the lung tissue of ALI mice induced by CLP, and downregulation of OGDH alleviated sepsis induced ALI. In animal models and cell models, the expression of OGDH was positively correlated with the expression of pro-inflammatory factors. OGDH may act through the MAPK pathway. CONCLUSIONS: Under the pathological condition of sepsis, OGDH amplifies the inflammatory response through the MAPK pathway, releases pro-inflammatory factors, and induces ALI.

GLP-1 Analog Liraglutide Improves Vascular Function in Polymicrobial Sepsis by Reduction of Oxidative Stress and Inflammation.

Sepsis causes high mortality in the setting of septic shock. LEADER and other trials revealed cardioprotective and anti-inflammatory properties of glucagon-like peptide-1 (GLP-1) analogs like liraglutide (Lira). We previously demonstrated improved survival in lipopolysaccharide (LPS)-induced endotoxemia by inhibition of GLP-1 degradation. Here we investigate the effects of Lira in the polymicrobial sepsis model of cecal ligation and puncture (CLP). C57BL/6J mice were intraperitoneally injected with Lira (200 µg/kg/d; 3 days) and sepsis induced by CLP after one day of GLP-1 analog treatment. Survival and body temperature were monitored. Aortic vascular function (isometric tension recording), protein expression (immunohistochemistry and dot blot) and gene expression (qRT-PCR) were determined. Endothelium-dependent relaxation in the aorta was impaired by CLP and correlated with markers of inflammation (e.g., interleukin 6 and inducible nitric oxide synthase) and oxidative stress (e.g., 3-nitrotyrosine) was higher in septic mice, all of which was almost completely normalized by Lira therapy. We demonstrate that the GLP-1 analog Lira ameliorates sepsis-induced endothelial dysfunction by the reduction of vascular inflammation and oxidative stress. Accordingly, the findings suggest that the antioxidant and anti-inflammatory effects of GLP-1 analogs may be a valuable tool to protect the cardiovascular system from dysbalanced inflammation in polymicrobial sepsis.

Using the Cecal Ligation and Puncture Model of Sepsis to Induce Rats to Multiple Organ Dysfunction.

Sepsis is a dysregulated hyperinflammatory disease caused by infection. Sepsis leads to multiple organ dysfunction syndrome (MODS), which is associated with high rates of mortality. The cecal ligation and puncture (CLP) model has been widely used in animals and has become the gold-standard method of replicating features of sepsis in humans. Despite several studies and modified CLP protocols, there are still open questions regarding the multifactorial determinants of its reproducibility and medical significance. In our protocol, which is also aimed at mimicking the sepsis observed in clinical practice, male Wistar rats are submitted to CLP with adequate fluid resuscitation (0.15 M NaCl, 25 ml/kg BW i.p.) immediately after surgery. At 6 h after CLP, additional fluid therapy (0.15 M NaCl, 25 ml/kg BW s.c.) and antibiotic therapy with imipenem-cilastatin (single dose of 14 mg/kg BW s.c.) are administered. The timing of the fluid and antibiotic therapy correspond to the initial care given when patients are admitted to the intensive care unit. This model of sepsis provides a useful platform for simulating human sepsis and could lay the groundwork for the development of new treatments.

Protective effect of pterostilbene on sepsis-induced acute lung injury in a rat model via the JAK2/STAT3 pathway.

BACKGROUND: Bacterial infection is one of the most common causes of sepsis, with acute lung injury (ALI) being a related complication. Pterostilbene (PTS) is extracted from blueberries, peanuts, and grapes, and has numerous pharmacologic activities. The aim of the present study was to explore the underlying role of PTS protects against sepsis-mediated ALI. METHODS: We established a sepsis model induced by cecal ligation and puncture (CLP) in rats. The rats were randomly divided into five groups (n=5 each): sham group, CLP group, Dexmedetomidine group (Dex, 50 µg/kg) and PTS groups (25 and 50 mg/kg). Twenty-hours hours after CLP, PTS was intraperitoneally injected for 14 continuous days. The rats were killed, and blood and lung tissue were collected for pathological analysis and mRNA and protein detection. RESULTS: Our findings showed that PTS reduced the wet/dry ratio and ameliorated sepsis-induced pulmonary fibrosis (PF), which was associated with improvement of pathological damage in lung tissues. We also observed the inhibitory effect of PTS on apoptosis and release of inflammatory cytokines (i.e., tumor necrosis factor-α, interleukin-6, and monocyte chemotactic protein 1). In addition, PTS markedly suppressed the phosphorylation levels of Janus kinase-2 (JAK2) and signal transducer and activator of transcription 3 (STAT3). CONCLUSIONS: Our results indicated that PTS inhibited the PF, apoptosis, and inflammatory response via the JAK2/STAT3 pathway in a sepsis-induced ALI rat model, providing a candidate for drug therapy of sepsis-induced ALI.

Anesthesia-Sepsis-Associated Alterations in Liver Gene Expression Profiles and Mitochondrial Oxidative Phosphorylation Complexes.

Background: Hepatic dysfunction plays a major role in adverse outcomes in sepsis. Volatile anesthetic agents may protect against organ dysfunction in the setting of critical illness and infection. The goal of this study was to study the impact of Sepsis-inflammation on hepatic subcellular energetics in animals anesthetized with both Propofol (intravenous anesthetic agent and GABA agonist) and Isoflurane (volatile anesthetic i.e., VAA). Methods: Sprague-Dawley rats were anesthetized with Propofol or isoflurane. Rats in each group were randomized to celiotomy and closure (control) or cecal ligation and puncture "CLP" (Sepsis-inflammation) for 8 h. Results: Inflammation led to upregulation in hepatic hypoxia-inducible factor-1 in both groups. Rats anesthetized with isoflurane also exhibited increases in bcl-2, inducible nitric oxide synthase, and heme oxygenase-1(HO-1) during inflammation, whereas rats anesthetized with Propofol did not. In rats anesthetized with isoflurane, decreased mRNA, protein (Complex II, IV, V), and activity levels (Complex II/III,IV,V) were identified for all components of the electron transport chain, leading to a decrease in mitochondrial ATP. In contrast, in rats anesthetized with Propofol, these changes were not identified after exposure to inflammation. RNA-Seq and real-time quantitative PCR (qPCR) expression analysis identified a substantial difference between groups (isoflurane vs. Propofol) in mitogen-activated protein kinase (MAPK) related gene expression following exposure to Sepsis-inflammation. Conclusions: Compared to rats anesthetized with Propofol, those anesthetized with isoflurane exhibit more oxidative stress, decreased oxidative phosphorylation protein expression, and electron transport chain activity and increased expression of organ-protective proteins.

The Fluctuations of Leukocytes and Circulating Cytokines in Septic Humanized Mice Vary With Outcome.

Sepsis remains a major challenge in translational research given its heterogeneous pathophysiology and the lack of specific therapeutics. The use of humanized mouse chimeras with transplanted human hematopoietic cells may improve the clinical relevance of pre-clinical studies. However, knowledge of the human immuno-inflammatory response during sepsis in humanized mice is scarce; it is unclear how similar or divergent mouse and human-origin immuno-inflammatory responses in sepsis are. In this study, we evaluated the early outcome-dependent immuno-inflammatory response in humanized mice generated in the NSG strain after cecal ligation and puncture (CLP) sepsis. Mice were observed for 32 h post-CLP and were assigned to either predicted-to-die (P-DIE) or predicted-to-survive (P-SUR) groups for retrospective comparisons. Blood samples were collected at baseline, 6 and 24 h, whereas the bone marrow and spleen were collected between 24 and 32 h post-CLP. In comparison to P-SUR, P-DIE humanized mice had a 3-fold higher frequency of human splenic monocytes and their CD80 expression was reduced by 1.3-fold; there was no difference in the HLA-DR expression. Similarly, the expression of CD80 on the bone marrow monocytes from P-DIE mice was decreased by 32% (p < 0.05). Sepsis induced a generalized up-regulation of both human and murine plasma cytokines (TNFα, IL-6, IL-10, IL-8/KC, MCP-1); it was additionally aggravated in P-DIE vs. P-SUR. Human cytokines were strongly overridden by the murine ones (approx. ratio 1:9) but human TNFα was 7-fold higher than mouse TNFα. Interestingly, transplantation of human cells did not influence murine cytokine response in NSG mice, but humanized NSG mice were more susceptible to sepsis in comparison with NSG mice (79 vs. 33% mortality; p < 0.05). In conclusion, our results show that humanized mice reflect selected aspects of human immune responses in sepsis and therefore may be a feasible alternative in preclinical immunotherapy modeling.

USP8 ameliorates cognitive and motor impairments via microglial inhibition in a mouse model of sepsis-associated encephalopathy.

Sepsis-associated encephalopathy (SAE) is a common and serious complication of sepsis, which is thought to be caused by neuroinflammation. In our previous study, ubiquitin-specific protease 8 (USP8), was reported to regulate inflammation in vitro. In the current study, we investigated whether increased USP8 expression would ameliorate the cognitive and motor impairments induced by cecal ligation and puncture (CLP) in mice, a model of SAE. Male adult mice were randomly divided into four groups: control, sham, CLP, and CLP + USP8 groups. The CLP + USP8 mice showed reduced weight loss on day 4 post-CLP, with a slight increase noted on day 7. The mortality rate in the CLP group was 70% 48 h after CLP; however, USP8 significantly improved survival after CLP. USP8 modulated the neurobehavioral scores in CLP mice. Our results also indicate that USP8 attenuated the CLP-induced cognitive and motor impairments, based on the performance of mice in the Morris water maze (MWM), pole-climbing, and wire suspension tests. USP8 suppressed the release of pro-inflammatory mediators, including prostaglandin E2(PGE2) in the serum and nitric oxide (NO) in brain tissue, as well as levels of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) in brain tissue. Immunofluorescence experiments revealed that USP8 inhibited CLP-induced increases in microglial size and density in the hippocampus, and protected hippocampal neurons. Our findings indicate that neuroinflammation occurs in the brains of CLP mice, and that USP8 exerts protective effects against CLP-induced neuroinflammation and cognitive and motor impairments, which may aid in the development of novel therapeutic strategies for SAE.

The inhibitor of interleukin-3 receptor protects against sepsis in a rat model of cecal ligation and puncture.

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. There are multiple cytokines involved in the process of sepsis. As an important upstream cytokine in inflammation, Interleukin-3 (IL-3) plays a crucial role during sepsis, however, its exact role is unclear. The purpose of this study is to discuss the role of IL-3 and its receptor in cecal ligation and puncture (CLP)-induced sepsis in a rat model. The Cluster of Differentiation 123 (CD123, IL-3 receptor alpha chain, IL-3Rac) antibody (anti-CD123) was used to directly target IL-3's receptor and alleviate the effect of IL-3 in the CLP + anti-CD123 group during the early stage of sepsis. CLP was performed in the CLP and CLP + anti-CD123 groups. The time points of observation included 12 h, 24 h, and 5d after the operation. The results showed that the rats in the CLP + anti-CD123 group had lower levels of lactate, serum tumor necrosis factor-α (TNF-α), Interleukin-1ß (IL-1ß), and Interleukin-6 (IL-6), and also exhibited a higher core temperature, mean arterial pressure (MAP), Oxygenation Index (PO2/FiO2), and end-tidal carbon dioxide (ETCO2) and serum Interleukin-10 (IL-10) levels after CLP than those in the CLP group. Additionally, administration of anti-CD123 led to a stable down-regulation of tyrosine phosphorylation of the IL-3 receptor, a decline in phosphorylation of the Janus kinase 2 (JAK2) protein, and the signal transduction and activation of transcription 5 (STAT5) proteins in lung tissues. Meanwhile, the study revealed that treatment of anti-CD123 can markedly attenuate histological damages in lung and kidney tissues, improve sublingual microcirculation, and prolong survival post sepsis. In conclusion, anti-CD123 reduces mortality and alleviates organ dysfunction by restraining the JAK2-STAT5 signaling pathway and reduces serum cytokines in the development of early sepsis in a rat model induced by CLP.

Peroxiredoxin 6 knockout aggravates cecal ligation and puncture-induced acute lung injury.

BACKGROUND: The aim of present study was to investigate the effects and mechanisms of peroxiredoxin (Prdx) 6 on cecal ligation and puncture (CLP) induced acute lung injury (ALI) in mice. METHODS: The cecal of male Prdx 6 knockout and wildtype C57BL/6J mice were ligated and perforated. Stool was extruded to ensure wound patency. Two hours, 4 h, 8 h and 16 h after stimulation, the morphology, wet/dry ratio, protein concentration in bronchial alveolar lavage fluid (BALF) were measured to evaluate lung injury. Myeloperoxidase (MPO) activity, hydrogen peroxide (H2O2), malondialdehyde (MDA), total superoxide dismutase (SOD), xanthine oxidase (XOD), CuZn-SOD, total anti-oxidative capability (TAOC), glutathione peroxidase (GSH-PX), catalase (CAT) in lungs were measured by assay kits. The mRNA expression of lung tumor necrosis factor (TNF-α), interleukin (IL)-1ß, and matrix metalloproteinases (MMP) 2 and 9 were tested by real-time RT-PCR. The nuclear factor (NF)-κB activity was measured by TransAM kit. RESULTS: CLP-induced ALI was characterized by inflammation in morphology, increased wet/dry ratio, elevated protein concentration in BALF and higher level of MPO activity. The levels of H2O2, MDA, and XOD were significantly increased and SOD, CuZn-SOD, GSH-PX, CAT, and T-AOC were significantly decreased in lungs after CLP. The activity of NF-κB was significantly increased and subsequently, the mRNA expression of TNF-α, IL-1ß and MMP2 and MMP9 were significantly increased after CLP. Those above injury parameters were more severe in Prdx 6 knockout mice than those in wildtype mice. CONCLUSIONS: Prdx 6 knockout aggravated the CLP induced lung injury by augmenting oxidative stress, inflammation and matrix degradation partially through NF-κB pathway.

Ulinastatin attenuates liver injury and inflammation in a cecal ligation and puncture induced sepsis mouse model.

Sepsis is a syndrome of life-threatening multiorgan dysfunction caused by host response dysregulation to infection. Ulinastatin (UTI), a serine protease inhibitor, possesses anti-inflammatory properties and has been suggested to modulate lipopolysaccharide-induced sepsis. However, little is known about the mechanism underlying its effects on sepsis. In the current study, we investigated the protective effect of UTI on liver injury in a cecal ligation and puncture (CLP)-induced sepsis of C57BL/6 mouse model and explored the possible mechanisms. Mice underwent CLP as sepsis models and were randomized into five groups including the sham group, UTI group, CLP group, UTI-L group, and UTI-H group. UTI was intraperitoneally administered at doses of UTI 1500 U/100 g (UTI-L group) or 3000 U/100 g (UTI-H group), before CLP. The mice were killed, and immunohistochemical changes, cytokine levels, and antioxidant enzyme activities were detected. Our results showed that UTI ameliorated CLP-mediated increases in serum aspartate aminotransferase and alanine aminotransferase activities, histological activity index, degenerative region ratio, and infiltrated inflammatory cell numbers. Moreover, UTI also decreased nitrotyrosine and 4-hydroxynonenal, activated caspase-3, and activated poly (ADP-ribose) polymerase (PARP) levels and inhibited the mitogen-activated protein kinase pathway activation in liver tissues. Our results indicated that UTI could inhibit CLP-induced liver injury by suppressing inflammation and oxidation. Our results indicated that UTI may serve as a potential therapeutic agent for sepsis.

Role of complement C5a and histones in septic cardiomyopathy.

Polymicrobial sepsis (after cecal ligation and puncture, CLP) causes robust complement activation with release of C5a. Many adverse events develop thereafter and will be discussed in this review article. Activation of complement system results in generation of C5a which interacts with its receptors (C5aR1, C5aR2). This leads to a series of harmful events, some of which are connected to the cardiomyopathy of sepsis, resulting in defective action potentials in cardiomyocytes (CMs), activation of the NLRP3 inflammasome in CMs and the appearance of extracellular histones, likely arising from activated neutrophils which form neutrophil extracellular traps (NETs). These events are associated with activation of mitogen-activated protein kinases (MAPKs) in CMs. The ensuing release of histones results in defective action potentials in CMs and reduced levels of [Ca2+]i-regulatory enzymes including sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2) and Na+/Ca2+ exchanger (NCX) as well as Na+/K+-ATPase in CMs. There is also evidence that CLP causes release of IL-1ß via activation of the NLRP3 inflammasome in CMs of septic hearts or in CMs incubated in vitro with C5a. Many of these events occur after in vivo or in vitro contact of CMs with histones. Together, these data emphasize the role of complement (C5a) and C5a receptors (C5aR1, C5aR2), as well as extracellular histones in events that lead to cardiac dysfunction of sepsis (septic cardiomyopathy).

Assessment of clinical sepsis-associated biomarkers in a septic mouse model.

Objective Clinical sepsis-associated biomarkers were utilized in a cecal ligation and puncture (CLP) septic mouse model to provide a reference for investigating pathophysiological mechanisms and evaluating novel therapeutic interventions for sepsis. Methods Sepsis in mice was induced by CLP, and clinical biomarkers were evaluated (survival rate, blood physiological and biochemical indices, cytokines, hepatorenal function parameters, and blood coagulation). Results The mortality rate was >70%. The body temperature, blood pressure, and heart rate decreased within 48 h. Low lactic acid was found at 8 h. The CLP mice showed typical inflammatory symptoms with decreased white blood cells and procalcitonin and increased levels of soluble triggering receptor expressed on myeloid cells-1, interleukin (IL)-6, IL-10, tumor necrosis factor-α, macrophage inflammatory protein (MIP)-1α, MIP-1ß, and MIP-2. The platelet count and activated partial thromboplastin time significantly decreased, and the prothrombin time and prothrombin time-international normalized ratio markedly increased. Phenotypes of multiple organ dysfunction were found in the CLP model, including increased liver alanine aminotransferase and aspartate transaminase; significantly reduced total protein, globulin, and serum albumin; increased blood urea nitrogen and creatinine; and decreased blood glucose. Conclusion The clinical features of the CLP mouse model were similar to those of human patients with sepsis.