Intravenous Injection Of Lipopolysaccharide Research Articles

Increased β2-adrenergic vasorelaxation at the early phase of endotoxemic shock in rats

Background and purposeThe early management of the cardiovascular dysfunction of septic shock is critical as it is associated with a poor outcome. Although the use of catecholamines is a common therapy in this syndrome, no data are available on the involvement of β-adrenoceptor (β-AR) subtypes and only few studies report an alteration of β-adrenergic-induced vasodilation in septic shock. The purpose of the study was to evaluate vascular β1, β2 and β3-AR expression and function in an endotoxemic rat model. Experimental approachEndotoxemia was induced in rats by intravenous injection of lipopolysaccharide (LPS). β1, β2 and β3-AR mRNA expression was evaluated by RT-PCR in aorta and vascular β1, β2 and β3-AR responses were determined on conducting (aorta) and/or resistance (mesenteric and renal) arteries by constructing relaxation curves in response to different β-AR agonists. ResultsThe maximal effect of isoproterenol decreased by 31 to 61% in the three vascular beds of LPS-treated rats compared to controls. In aortas from LPS-treated rats, β1 and β3-AR mRNA expression was decreased and associated to a reduced β1 and β3-induced vasodilation. Conversely, albeit β2-AR mRNA was unchanged, the maximal β2-AR-induced vasodilation increased by 49% in aortas from LPS-treated rats compared to controls. This increase was not affected by endothelium removal but was abolished in the presence of a β2-AR antagonist or an adenylate cyclase inhibitor. ConclusionsIn endotoxemia, β2-AR vasodilation was increased by a potential recruitment of β2-AR located on smooth muscle cells. This study suggests that vascular β2-AR should be a putative new therapeutic target in septic shock.

Blockade or deletion of transient receptor potential vanilloid 4 (TRPV4) is not protective in a murine model of sepsis.

Sepsis is a systemic inflammatory response triggered by microbial infection that can cause cardiovascular collapse, insufficient tissue perfusion and multi-organ failure. The cation channel transient receptor potential vanilloid 4 (TRPV4) is expressed in vascular endothelium and causes vasodilatation, but excessive TRPV4 activation leads to profound hypotension and circulatory collapse - key features of sepsis pathogenesis. We hypothesised that loss of TRPV4 signaling would protect against cardiovascular dysfunction in a mouse model of sepsis (endotoxaemia). Multi-parameter monitoring of conscious systemic haemodynamics (by radiotelemetry probe), mesenteric microvascular blood flow (laser speckle contrast imaging) and blood biochemistry (iSTAT blood gas analysis) was carried out in wild type (WT) and TRPV4 knockout (KO) mice. Endotoxaemia was induced by a single intravenous injection of lipopolysaccharide (LPS; 12.5 mg/kg) and systemic haemodynamics monitored for 24 h. Blood flow recording was then conducted under terminal anaesthesia after which blood was obtained for haematological/biochemical analysis. No significant differences were observed in baseline haemodynamics or mesenteric blood flow. Naïve TRPV4 KO mice were significantly acidotic relative to WT counterparts. Following induction of sepsis, all mice became significantly hypotensive, though there was no significant difference in the degree of hypotension between TRPV4 WT and KO mice. TRPV4 KO mice exhibited a higher sepsis severity score. While septic WT mice became significantly hypernatraemic relative to the naïve state, this was not observed in septic KO mice. Mesenteric blood flow was inhibited by topical application of the TRPV4 agonist GSK1016790A in naïve WT mice, but enhanced 24 h following LPS injection. Contrary to the initial hypothesis, loss of TRPV4 signaling (either through gene deletion or pharmacological antagonism) did not attenuate sepsis-induced cardiovascular dysfunction: in fact, pathology appeared to be modestly exaggerated in mice lacking TRPV4. Local targeting of TRPV4 signalling may be more beneficial than global inhibition in sepsis treatment.

Neural circuitry mediating inflammation-induced central pain amplification in human experimental endotoxemia.

To elucidate the brain mechanisms underlying inflammation-induced visceral hyperalgesia in humans, in this functional magnetic resonance imaging (fMRI) study we tested if intravenous administration of lipopolysaccharide (LPS) involves altered central processing of visceral pain stimuli. In this randomized, double-blind, placebo-controlled fMRI study, 26 healthy male subjects received either an intravenous injection of low-dose LPS (N=14, 0.4 ng/kg body weight) or placebo (N=12, control group). Plasma cytokines (TNF-α, IL-6), body temperature, plasma cortisol and mood were assessed at baseline and up to 6 h post-injection. At baseline and 2 h post-injection (test), rectal pain thresholds and painful rectal distension-induced blood oxygen level-dependent (BOLD) responses in brain regions-of-interest were assessed. To address specificity for visceral pain, BOLD responses to non-painful rectal distensions and painful somatic stimuli (i.e., punctuate mechanical stimulation) were also analyzed as control stimuli. Compared to the control group, LPS-treated subjects demonstrated significant and transient increases in TNF-α, IL-6, body temperature and cortisol, along with impaired mood. In response to LPS, rectal pain thresholds decreased in trend, along with enhanced up-regulation of rectal pain-induced BOLD responses within the posterior insula, dorsolateral prefrontal (DLPFC), anterior midcingulate (aMCC) and somatosensory cortices (all FWE-corrected p<0.05). Within the LPS group, more pronounced cytokine responses correlated significantly with enhanced rectal pain-induced neural activation in DLPFC and aMCC. No significant LPS effects were observed on neural responses to non-painful rectal distensions or mechanical stimulation. These findings support that peripheral inflammatory processes affect visceral pain thresholds and the central processing of sensory-discriminative aspects of visceral pain.

Protective effects of L‐cysteine against LPS‐induced liver injuries.

An activation of Kupffer cells (hepatic resident macrophages) and hepatic stellate cells (HSCs) plays an important role in lipopolysaccharide (LPS)‐induced liver injury. It is known that the upregulated production of ET‐1 by Kupffer cells in response to LPS stress activates HSCs and induces subsequent pathophysiological change in the liver. Recently, it has been reported that some amino acids exhibit anti‐inflammatory effects. In a preliminary experiment, using 20 amino acids, we investigated the effect of amino acid administration on ET‐1 production in the mouse macrophage cell lines (RAW 264.7). Among the amino acids, L‐cysteine, L‐glutamine, L‐leucine, L‐alanine, and Glycine suppressed LPS‐induced ET‐1 production in a dose‐dependent fashion. The effect was strongest by an administration of L‐cysteine. L‐cysteine also suppressed a ET‐1‐induced contraction of collagen gel lattices cultured with HSCs. Moreover, an increased [Ca2+]i in response to ET‐1 administration in HSCs measured with the fluorescent dye fura‐2 was strongly attenuated with the presence of L‐cysteine in a culture medium. In an in vivo experiment, Wister rats were pre‐treated with L‐cysteine or saline and received intravenous injection of LPS. Increased levels of liver function tests following LPS was attenuated by L‐cysteine treatment. These results indicated that L‐cysteine may lead to a beneficial effect in LPS‐induced liver injury.

Protective effect of continuous intravenous infusion of Isoproterenol on myocardial mitochondria of early septic rats and the corresponding mechanism

Objective To investigate the protective effect of continuous intravenous infusion of Isoproterenol (ISO)on myocardial mitochondria of early septic rats and the corresponding mechanism. Methods Thirty Sprague Dawley (SD)rats were randomly divided into 5 groups (6 cases per group): control group, endotoxin group, ISO small-dose group, ISO medium-dose group and ISO large-dose group.Endotoxin group and ISO intervene group received same management apart from drug intervention: receiving intravenous injection of lipopolysaccharide (LPS)10 mg/kg followed by an continuous intravenous infusion of 9 g/L saline 1 mL/h or ISO 0.06 μg/(kg·min), 0.30 μg/(kg·min)and 0.60 μg/(kg·min). Control group received intraperitoneal injection and continuous intravenous infusion with the same amount of 9 g/L saline.The primary endpoint of the study was 24 hours after injection of 9 g/L saline or LPS.Serum creatine kinase (CK)and creatine kinase isoenzyme (CK-MB), oxidative and nitrosative stress levels and swelling of isolated heart mitochondrion were detected.The pathological changes of the myocardium and morphologic changes of the heart mitochondria were observed through light microscope and scanning electron microscope, respectively. Results The levels of CK, CK-MB, nitric oxide (NO)content, inducible nitric oxide synthase (iNOS)activity and malondialdehyde (MDA)content in endotoxin group were increased compared with control group (all P<0.05), while the superoxide dismutase (SOD) activity decreased [(11.543±1.080) U/mg prot vs (9.892±0.815) U/mg prot, P<0.05]. The morphology of the heart mitochondria significantly changed (such as swelling, disordered arrangement, crest fracture, fusion and cavitations, and so on). ISO intervention significantly decreased the levels of CK, CK-MB and mitochondrial swelling (all P<0.05)and increased the SOD activity (all P<0.05). The levels of NO content, iNOS activity and MDA content were significantly decreased in small-dose group[(10.823±2.240) μmol/g prot vs (7.917±2.203) μmol/g prot, (0.045±0.008) U/mg prot vs (0.033±0.003) U/mg prot, (1.663±0.618) mmol/mg prot vs (0.768±0.312) mmol/mg prot, all P<0.05], while the levels of iNOS activity and MDA content were significantly increased in medium- and large-dose group (all P<0.05); compared with medium-dose group, the degree of mitochondrial swelling in large-dose group increased (1.160±0.186 vs 1.393±0.128, P<0.05). The pathological changes of the myocardium mitochondria significantly improved. Conclusions The myocardium and myocardial mitochondria of early septic rats were damaged, continuous intravenous infusion of low-dose ISO revealed protective effect on these damages, and the corresponding mechanism may relate to the decrease of the oxidative and nitrosative stress. Key words: Isoproterenol; Lipopolysaccharide; Sepsis; Oxidative stress; Mitochondrion

Flurbiprofen axetil preconditioning allivates inhalation lung injury in rats

Objective To investigate the protective effects of flurbiprofen axetil(FA)on inhalation lung injury induced by lipopolysaccharides(LPS)inhalation in rats,so as to provide evidence for applying FA in treating inhalation lung injury in clinic.Methods A total of 96 adult male Sprague-Dawley rats were evenly randomized into four groups(n=24):saline negative control group(NS group),model group(LPS group),lipid emulsion preconditioning control group(Lip+LPS group),and FA preconditioning group(FA+LPS group).The model of inhalation lung injury was established with endotracheal instillation of LPS(1mL/kg)in all experimental groups.NS group was identical to the other three groups except that saline(1mL/kg)was administered instead of LPS.Lipid emulsion(20%,1mL/kg)or FA injection(1mL/kg,10mg/mL)was intravenously injected via vena caudalis 1hour before LPS in Lip+LPS and FA+LPS groups,respectively.Rats were sacrificed at 1h,6h,12hand24 hafter LPS injection and assigned to 1h,6h,12 hand 24hsubgroups(n=6).The arterial blood gas was analyzed and the lungs were removed for determination of the wet/dry mass(W/D)ratio and evaluation of histological injury in all groups.Real-time PCR was used to detect the mRNA levels of PPAR-αand PPAR-γin rats lung homogenates.The concentration of tumor necrosis factor-alpha(TNF-α)in rat serum was determined by ELISA.Results The rats in LPS and Lip+LPS groups showed damaged structure of lung tissue and inflammation.The mRNA levels of PPAR-αand PPAR-γin the lung tissues of LPS group were significantly lower than those of NS group(P0.05).The serum concentration of TNF-αof LPS group was significantly higher than that of NS group(P0.05).The pulmonary lesions in FA+LPS group were ameliorated compared with those in LPS and Lip+LPS groups.Pressure of oxygen in arterial blood(PaO2)was signficantly higher and semiquantitative pathological score of lung was signficanlty lower in FA+LPS group than those in LPS and Lip+LPS group at 6h,12 hand 24hafter injection(P0.05).The mRNA levels of PPAR-αand PPAR-γin rat lung tissues of FA+LPS group were signficanlty higher than those of LPS and Lip+LPS groups at all times,especially,at 6hafter the intravenous injection of LPS(P0.05).The serum concentration of TNF-αof FA+LPS group was significantly lower than that of LPS and Lip+LPS groups at all times,expecially,at 1hafter the intravenous injection of LPS(P0.05).Conclusion FA preconditioning can alleviate the inflammation and protect inhalation injury to lung tissues induced by LPS in rats,which may involve the upregulation of PPAR-αand PPAR-γ mRNA levels in rat lung tissues and the down-regulation of serum TNF-α.

Penehyclidine hydrochloride postconditioning on lipopolysaccharide-induced acute lung injury by inhibition of inflammatory factors in a rodent model

BackgroundSepsis is associated with acute lung injury (ALI) and high mortality. The aim of this study was to investigate the effects of different doses of penehyclidine hydrochloride (PHC) postconditioning on ALI induced by sepsis in a rat model. MethodsA rat model of ALI was induced by intravenous injection of lipopolysaccharide (LPS). The different doses of PHC were administrated intravenously at 30 min after LPS administration (low dose, 0.3 mg/kg; medium dose, 1.0 mg/kg, and high dose, 3.0 mg/kg). After 6 h, arterial blood samples were obtained for blood gas analyses. Meanwhile, lung tissue was harvested and lung injury was assessed by the histopathologic changes (hematoxylin and eosin staining) and wet-to-dry lung weight ratio. The tumor necrosis factor-α and interleukin-6 levels in bronchoalveolar lavage fluid, as well as the nuclear factor-kappa B protein expressions, and the myeloperoxidase activities in lung tissues were measured by immunohistochemistry or enzyme-linked immunosorbent assay, respectively. ResultsLPS-induced severe lung injury evidenced by increased pathologic scores and lung wet-to-dry weight ratio, which was accompanied by increases in the expression of pulmonary nuclear factor-kappa B protein and the activity of pulmonary myeloperoxidase and the levels of interleukin-6 and tumor necrosis factor-α in bronchoalveolar lavage fluid. The arterial oxygen tension (PaO2), pH, and the PaO2/fraction of inspired oxygen ratio (PaO2/FiO2) decreased significantly and the carbon dioxide tension (PaCO2) increased notedly after an LPS injection. All doses of PHC could significantly ameliorate lung injury and improve the previously mentioned variables (P < 0.05 or 0.01). Furthermore, the protection of medium dose (1.0 mg/kg) could be better than that of low or high dose. ConclusionsThese findings indicated that different doses of PHC, especially to medium dose, could prevent LPS-induced ALI in rats, at least in part, by inhibiting inflammatory response. Moreover, the protection of pharmacologic postconditioning with PHC is limited by a “ceiling effect.”

Roles of Toll-Like Receptor 4, IκB Kinase, and the Proteasome in the Intestinal Alterations Caused by Sepsis.

Lipopolysaccharide decreases intestinal contractility and induces the production of cytokines, which play an important role in the pathogenesis of sepsis. The objective of the present study was to examine the role of Toll-like receptor 4, IκB kinase, and the proteasome in the intestinal alterations induced by lipopolysaccharide. Sepsis was induced in rabbits by intravenous injection of lipopolysaccharide. Contractility studies of rabbit duodenum were performed in an organ bath. Expressions of interleukin-1β, interleukin-6, interleukin-8, interleukin-10, IκB kinase-α, IκB kinase-β, IκB kinase-γ, and the proteasome mRNA were determined by RT-PCR on rabbit duodenum. Neomycin and polymyxin B (Toll-like receptor 4 inhibitors), IKK NBD peptide (IκB kinase complex inhibitor), and MG-132 (proteasome inhibitor) blocked partially the effects of lipopolysaccharide on the acetylcholine-, prostaglandin E2-, substance P-, and KCl-induced contractions in the longitudinal and circular smooth muscle of rabbit duodenum. Lipopolysaccharide increased the mRNA expression of interleukin-6 and interleukin-8 in duodenal tissue, and this effect was partly reversed by neomycin, polymyxin B, IKK NBD peptide, and MG-132. IκB kinase-α, IκB kinase-β, IκB kinase-γ, and the proteasome mRNA expressions was not affected by lipopolysaccharide treatment. Toll-like receptor 4, the IκB kinase complex, and the proteasome could be therapeutic targets in the treatment of sepsis symptoms in the intestine.

Anti-inflammatory effects of Reduning Injection on lipopolysaccharide-induced acute lung injury of rats.

ObjectiveTo evaluate the protective effects of Reduning Injection (热毒宁注射液, RDN), a patent Chinese medicine, on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats and its underlying mechanisms of action.MethodsSixty male Sprague-Dawley rats were randomly divided into 6 groups, including normal control, model, dexamethasone (DEX, 5 mg/kg), RDN-H (720 mg/kg), RDN-M (360 mg/kg) and RDN-L (180 mg/kg) groups, with 10 rats in each group. Rats were challenged with intravenous injection of LPS 1 h after intraperitoneal treatment with RDN or DEX. At 6 h after LPS challenge, lung tissues and bronchoalveolar lavage fluid (BALF) were collected, and the number of inflammatory cells was determined. The right lungs were collected for histopathologic examination, measurement of gene and protein expressions, superoxide dismutase (SOD) and myeloperoxidase (MPO) activities.Results In vivo pretreatment of RDN (360, 720 mg/kg) significantly reduced the weight of wet to dry (W/D) ratio of lung, protein content in BALF, and led to remarkable attenuation of LPS-induced histopathological changes in the lungs. Meanwhile, RDN enormously decreased BALF total inflammatory cells, especially neutrophil and macrophage cell numbers. Moreover, RDN increased SOD activity, inhibited MPO activity, alleviated LPS-induced tumor neurosis factor-α (TNF-α) and inducible nitric oxide synthase (iNOS) expression in lung tissues. Furthermore, RDN (720 mg/kg) efficiently weakened nuclear factorkappa B (NF-κB) gene and protein expression.ConclusionAnti-inflammatory effects of RDN was demonstrated to be preventing pulmonary neutrophil infiltration, lowering MPO activity, TNF-α and iNOS gene expression by inhibiting NF-κB activity in LPS-induced ALI.

English

This study aimed to investigate the antifebrile and anti-inflammatory effect of Huanglian Jiedu Decoction (HLJDD). The rabbits received intravenous injection of lipopolysaccharide (LPS) after orally administered with HLJDD and the rectal temperatures of rabbits were monitored. The concentrations of interleukin-1 beta (IL-1&beta;) and tumor necrosis factor alpha (TNF-&alpha;) in serum were assayed using rabbit IL-1&beta; and TNF-&alpha; enzyme-linked immunosorbent assay (ELISA) kits. Carrageenan-induced paw edema in rats and the anti-inflammatory effects of HLJDD were also explored. HLJDD treatment group resulted in a significant fall in body temperature in biphasic fever peak (p &lt; 0.05), and there were no significant differences between HLJDD treatment group and Ibuprofen (IBR) treatment group in biphasic fever peak at time 1 and 3 h (p &gt; 0.05). HLJDD treatment group reduced the concentrations of IL-1&beta; in serum at time 1 and 3 h to control febrile responses. Moreover, paw edema of carrageenan-treated rats were significantly attenuated in rats pretreated with HLJDD. Mechanistic studies showed that HLJDD effectively decreased expressions of COX-2 and inducible nitric oxide synthase (iNOS) proteins. These results suggested that HLJDD would be a valuable candidate for further investigation as a new anti-arthritic drug. Key words: Lipopolysaccharide, Huanglian Jiedu Decoction (HLJDD), anti-inflammatory, interleukin-1 beta, tumor necrosis factor alpha.

Bovine lactoferrin ingestion protects against inflammation via IL-11 induction in the small intestine of mice with hepatitis

Accumulating evidence suggests that orally ingested lactoferrin protects against inflammation. To assess the efficacy of orally administered bovine lactoferrin (bLF) against hepatitis and to identify the underlying mechanism, in the present study, we used four mouse models of hepatitis induced by d-galactosamine (GalN), carbon tetrachloride (CCl4), GalN plus lipopolysaccharide (LPS) and zymosan plus LPS. Intraperitoneal (i.p.) injection of GalN (500mg/kg body weight) in mice treated with bovine serum albumin (BSA) for 14d significantly increased serum aspartate aminotransferase (AST) concentrations compared with the untreated mice. However, orally administered bLF reduced AST concentrations compared with BSA treatment. In mice that received a single injection (0·4ml/kg) and twice-weekly injections (0·08ml/kg) of CCl4 for 24 weeks and pretreated with bLF for 14d and 24 weeks, respectively, significantly suppressed alanine aminotransferase and AST concentrations were observed compared with the BSA-treated control. Oral administration of bLF for 14d before i.p. injection of LPS (5mg/kg) plus GalN (1g/kg) significantly improved the survival rate. In mice that received intravenous injection of zymosan (25mg/kg) and LPS (15μg/kg) at 7d intervals, bLF reduced the elevation of AST concentrations and enhanced the production of IL-11 and bone morphogenetic protein 2 in the small intestine compared with the BSA-treated control. To evaluate the effects of IL-11, we used IL-11 receptor α-null mice treated with GalN, CCl4 and zymosan plus LPS. In this group, the activity of bLF was not significantly different from that of BSA. These data indicate that orally ingested bLF enhances the expression of IL-11 in the small intestine and up-regulates protective activity in mice with hepatitis.

Experimental cannabinoid 2 receptor-mediated immune modulation in sepsis.

Sepsis is a complex condition that results from a dysregulated immune system in response to a systemic infection. Current treatments lack effectiveness in reducing the incidence and mortality associated with this disease. The endocannabinoid system offers great promise in managing sepsis pathogenesis due to its unique characteristics. The present study explored the effect of modulating the CB2 receptor pathway in an acute sepsis mouse model. Endotoxemia was induced by intravenous injection of lipopolysaccharide (LPS) in mice and intestinal microcirculation was assessed through intravital microscopy. We found that HU308 (CB2 receptor agonist) reduced the number of adherent leukocytes in submucosal venules but did not restore muscular and mucosal villi FCD in endotoxemic mice. AM630 (CB2 receptor antagonist) maintained the level of adherent leukocytes induced by LPS but further reduced muscular and mucosal villi FCD. URB597 (FAAH inhibitor) and JZL184 (MAGL inhibitor) both reduced the number of adherent leukocytes in submucosal venules but did not restore the mucosal villi FCD. Using various compounds we have shown different mechanisms of activating CB2 receptors to reduce leukocyte endothelial interactions in order to prevent further inflammatory damage during sepsis.

Effects of ketamine, propofol, and ketofol on proinflammatory cytokines and markers of oxidative stress in a rat model of endotoxemia-induced acute lung injury.

Intravenous lipopolysaccharide (LPS) leads to acute lung injury (ALI) in rats. The purpose of this study was to examine the anti-inflammatory and antioxidant efficacy of ketamine, propofol, and ketofol in a rat model of ALI. We induced ALI in rats via intravenous injection of LPS (15 mg kg(-1)). The animals were randomly separated into five groups: control, LPS only, LPS + ketamine (10 mg·kg(-1)·h(-1)), LPS + propofol (10 mg·kg(-1)·h(-1)), LPS + ketofol (5 mg·kg(-1)·h(-1) ketamine + 5 mg·kg(-1)·h(-1) propofol). LPS resulted in an increase in the release of pro-inflammatory cytokines, mRNA expression related with inflammation, production of nitric oxide, and lipid peroxidation. Ketamine prevented the increase in markers of oxidative stress and inflammation mediators, both in plasma and lung tissue. Propofol decreased the levels of cytokines in plasma and lung tissue, whereas it had no effect on the IL-1-beta level in lung tissue. Ketamine downregulated mediators of lung tissue inflammation and reduced the level of circulating cytokines and protected lung tissue against lipid peroxidation. Ketofol decreased the level of TNF-α and IL-1β in plasma, as well as expression of cyclooxygenase-2 mRNA and the nitrate/nitrite level in lung tissue. The results of this investigation support the hypothesis that ketamine may be effective in preventing ALI.

S100A12 and Soluble Receptor for Advanced Glycation End Products Levels During Human Severe Sepsis

S100A12 is highly expressed, and serum levels correlate with individual disease activity in patients with inflammatory diseases. We here sought to determine the extent of S100A12 release and its soluble high-affinity receptor for advanced glycation end products (sRAGE) in patients with severe sepsis stratified to the three most common infectious sources (lungs, abdomen, and urinary tract) and to determine S100A12 and sRAGE concentrations at the site of infection during peritonitis. Two patient populations were studied: (a) 51 patients with sepsis due to (i) peritonitis (n = 12), (ii) pneumonia (n = 29), or (iii) urinary tract infection (n = 10); and (b) 17 patients with peritonitis. In addition, eight healthy humans were studied after intravenous injection of lipopolysaccharide (4 ng/kg). Compared with healthy volunteers, patients with severe sepsis displayed increased circulating S100A12 concentrations at day 0 (591.2 ± 101.0 vs. 106.2 ± 15.6 ng/mL [control subjects], P < 0.0001) and at day 3 (637.2 ± 111.2 vs. 106.2 ± 15.6 ng/mL [control subjects], P < 0.0001). All three severe sepsis subgroups had elevated serum S100A12 concentrations at both time points (sepsis due to [i] peritonitis [393.5 ± 89.9 at day 0 and 337.9 ± 97.2 at day 3 vs. 106.2 ± 15.6 ng/mL, control subjects, P < 0.005 and P < 0.05, respectively]; [ii] pneumonia [716.9 ± 167.0 at day 0 and 787.5 ± 164.7 at day 3 vs. 106.2 ± 15.6 ng/mL, control subjects, both P < 0.0001]; and [iii] urinary tract infection [464.2 ± 115.6 at day 0 and 545.6 ± 254.9 at day 3 vs. 106.2 ± 15.6 ng/mL, control subjects, P < 0.0001 and P < 0.05, respectively]). Remarkably, patients with sepsis due to pneumonia had the highest S100A12 levels (716.9 ± 167.0 and 787.5 ± 164.7 ng/mL at days 0 and 3, respectively). S100A12 levels were not correlated to either Acute Physiology and Chronic Health Evaluation II scores (r = -0.185, P = 0.19) or Sepsis-Related Organ Failure Assessment scores (r = -0.194, P = 0.17). Intravenous lipopolysaccharide injection in healthy humans elevated systemic S100A12 levels (peak levels at 3 h of 59.6 ± 22.0 vs. 12.4 ± 3.6 ng/mL; t = 0 h, P < 0.005). In contrast to S100A12, sRAGE concentrations did not change during severe sepsis or human endotoxemia. During peritonitis, S100A12 concentrations in abdominal fluid (12945.8 ± 4142.1 ng/mL) were more than 100-fold higher than in concurrently obtained plasma (121.2 ± 80.4 ng/mL, P < 0.0005), whereas sRAGE levels in abdominal fluid (148.8 ± 36.0 pg/mL) were lower than those in plasma (648.7 ± 145.6 pg/mL, P < 0.005) and did not increase. In conclusion, in severe sepsis, S100A12 is released systemically irrespective of the primary source of infection. During abdominal sepsis, S100A12 release likely predominantly occurs at the site of infection. Concentrations of its high-affinity sRAGE do not change during infection or human endotoxemia.

Relationship between iNOS expression and apoptosis in cerebral tissue, and the effect of Sini injection in endotoxin shock rats

ObjectiveTo investigate the dynamic changes and relationship of inducible nitric oxide synthase (iNOS) and apoptosis in endotoxin shock rats, as well as the effects of Sini injection. MethodsIn total, 102 Sprague-Dawley (SD) rats were randomly divided into a normal group (n=6, NG), sham operation group (n=24, OG), model group (n=24, MG), dexamethasone group (n=24, DG), and Sini group (n=24, SG). The endotoxin shock model was induced by an intravenous injection of lipopolysaccharide (LPS) (8 mg/kg). Rats in the OG, MG, DG, and SG groups were further divided into 4 groups: 1, 2, 3 and 6 h after shock groups (n=6 per group). iNOS expression was detected by immunohistochemistry. Terminal Deoxynucleotidyl Transferase Mediated Deoxyuridine Triphosphate-biotin Nick End Labeling (TUNEL) was employed to measure apoptosis. ResultsNo iNOS expression was found in the OG group. Compared with the OG group, iNOS expression in the MG group was markedly elevated, reached a peak at 1 h (P<0.01), decreased at 2 and 3 h, and rebounded at 6 h. Compared with the MG group, iNOS expression decreased significantly in both the DG (P<0.05) and SG (P<0.01) groups at 6 h. The number of apoptotic cells in the MG group was markedly increased than that in the NG and OG (P<0.01) groups, and reached a peak at 6 h. The number of apoptotic cells in the DG group at 1 and 2 h (P<0.01) and SG group at 2, 3 and 6 h (P<0.01) decreased when compared with the MG group. ConclusionSini injection can significantly inhibit NO generation, which decreases apoptosis and subsequently protects the brain from endotoxic shock.

Expression change of TNF–α in myocardium and hepatic tissue of rats with compound stress of hyperthermia and lipopolysaccharide

ObjectiveTo investigate the expression characteristics of TNF-α in myocardium and hepatic tissue of rats with compound stress of hyperthermia and lipopolysaccharide (LPS). MethodsMale SPF Wistar rats were randomly divided into room temperature+physiological saline group (Group C), hyperthermia+physiological saline group (Group H), room temperature+LPS group (Group L) and hyperthermia+LPS group (Group HL). The rats were put in simulated climate cabin. Group HL and Group H were exposed in the environment at a dry bulb temperature (TDB) of (35.0±0.5) °C, while Group L and Group C were exposed in the environment at a TDB of (26.0±0.5) °C. The rats in Group HL and Group L were given tail intravenous injection of LPS 10 mg/kg, while the rats in Group H and Group C were given tail intravenous injection of 9 g/L NaCl 10 mL/kg. After the stress, immunohistochemical SABC staining method was used to detect the expression characteristics of TNF-α in myocardium and hepatic tissue of rats, and those rats were given routine pathological examinations. ResultsThe expression of TNF-α in myocardium and hepatic tissue in Group HL was enhanced remarkably, and the tissue damages of Group HL were severest. ConclusionsThe eardiotoxieity and hepatotoxicity caused by compound stress of hyperthermia and LPS is closely related to the expression of TNF-α.

Magnolol Pretreatment Prevents Sepsis-Induced Intestinal Dysmotility by Maintaining Functional Interstitial Cells of Cajal

The purpose of this study was to investigate the mechanism by which magnolol treatment prevents lipopolysaccharide (LPS)-induced septic dysmotility in mice. Sepsis was induced by intravenous tail vein injection of LPS (4 mg/kg body weight). Animals were divided into three groups: the magnolol-treated septic group, the placebo-treated septic group, and the control group. Intestinal transit and circular smooth muscle contraction were measured 12 h after LPS injection, and immunocytochemisty was performed to study the morphology of interstitial cells of Cajal (ICCs). Stem cell factor (SCF) expression and c-kit phosphorylation were determined by Western blot analysis, and the mRNA levels of inducible NO synthase (iNOS) were determined by RT-PCR. Nitric oxide (NO) content, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) concentration were detected using commercial kits. Intestinal transit and muscular contractility were significantly lower in the LPS-treated group than in the control group. Immunocytochemical experiments showed that the total number of ICCs, and the total and average lengths of the ICC processes were significantly decreased in the LPS-treated group compared with those in the control group. In LPS-treated animals, magnolol pretreatment significantly accelerated intestinal transit, increased circular muscle contraction, and prevented ICC morphology changes. Phosphorylation of c-kit and expression of SCF were significantly downregulated in LPS-treated animals compared with control animals. Magnolol pretreatment prevented sepsis-induced decreases in c-kit phosphorylation and SCF expression in LPS-treated animals. Magnolol pretreatment prevented the sepsis-induced increase in NO concentration, iNOS expression, and MDA concentration, and decrease in SOD activity in LPS-treated animals. Our results suggest that magnolol treatment prevents sepsis-induced intestinal dysmotility by regulating SCF/c-kit and NO signaling to maintain functional ICCs.

Protective effects of recombinant human erythropoietin on acute lung injury induced by sepsis in rats

Objective To investigate the protective effects of recombinant human erythropoietin (rHuEPO) on acute lung injury (ALI) induced by lipopolysaccharide (LPS).Methods Fourty-five rats were randomly (random number) assigned to three groups,namely control group,model group,and rHuEPO group.ALI was induced by intravenous injection of LPS (6 mg/kg).The rHuEPO (5000 U/kg) was injected intravenously into rats 60 min before LPS challenge.The general status of rats was observed.Twelve hours after modeling,the rats were sacrificed and the tissue samples including lung tissue and blood were collected.PaO2,PaCO2,pH,the lung wet/dry weight ratio,plasma cytokines [interleukin (IL) IL-6 and tumor necrosis factor-alpha (TNF-α)],and inducible nitric oxide synthase (iNOS) were detected.Cytokines were assayed with ELISA method.Pathological changes of lung tissues were observed under light microscope and transmission electron microscopy.Results (1) Compared with the control group,PaO2,pH in the model group and in the rHuEPO group were significantly lower (P ＜ 0.05),and PaCO2 were significantly higher (P ＜ 0.05).Compared with the model group,PaO2,pH in the rHuEPO group were significantly higher (P ＜ 0.05),and PaCO2 were significantly lower (P ＜ 0.05).(2) Compared with the control group,the W/D weight ratio of lung tissues in the model group and the rHuEPO group was significantly higher (P ＜ 0.05).Compared with the model group,the W/D weight ratio of lung tissues in the rHuEPO group significantly lower (P ＜ 0.05).(3) The levels of TNF-o,IL-6 and iNOS in serum of rats in the control group were lower than those in the model group and the rHuEPO group (P ＜0.01).The serum levels of TNF-α,IL-6 and iNOS of rats in the rHuEPO group were significantly lower compared with the model group (P ＜ 0.01).(4) The light microscopy and the transmission electron microscopy showed the model group had histopathologic changes with acute diffuse lung injury manifested by intra-alveolar hemorrhage,exudate,inflammatory cells infiltration,Ⅰ type and Ⅱ type epithelial cell necrosis and detachment,and the pathological changes of lung tissue in the rHuEPO group were not as serious as those in the LPS group,showing only a little inflammatory cells infiltration of focal alveoli.Conclusions Recombinant human erythropoietin can inhibit the genesis of TNF-α,IL-6 and iNOS in serum,modifying the inflammatory response and providing protective effects against acute lung injury induced by sepsis. Key words: Recombinant human erythropoietin ; Lipopolysaccharides ; Sepsis ; Acute lung injury

Effects of Bai-Hu decoction on fever induced by lipopolysaccharide

This study was designed to investigate the antifebrile effect and mechanisms of Bai-Hu decoction (BHD), a traditional Chinese medical (TCM) prescription. The rabbits used in this study received an intravenous injection of lipopolysaccharide (LPS) after being orally administered with BHD, ibuprofen, or saline, and their rectal temperatures were monitored by a copper–constantan thermocouple. Concentrations of interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) in serum and hypothalamus were assayed using the commercially available rabbit IL-1β and TNF-α enzyme-linked immunosorbent assay kits following the manufacturer’s instructions. The BHD treatment group exhibited a significant fall in body temperature in both peaks compared with the LPS group (p<0.05). BHD reduced the concentrations of IL-1β and TNF-α in serum, and of TNF-α in hypothalamus to control the febrile responses at 1 hour. Besides the levels of IL-1β in hypothalamus and serum, the concentration of TNF-α in hypothalamus was decreased remarkably in the BHD group than in the LPS group at 3 hours. The main findings, the partial mechanisms of BHD in reducing biphasic fever elicited by LPS, were that treatments with the crude extract of BHD could remarkably reduce the increased concentrations of IL-1β and TNF-α, not only in serum but also in hypothalamus. The results indicated that BHD would be a valuable candidate for further investigation as a traditional antifebrile and anti-inflammatory natural drug.

The effects of postconditioning with propofol on Toll-like receptor 4 expression in the lung tissue of rat with acute lung injury

To investigate the effect of postconditioning with propofol on Toll-like receptor 4 (TLR4) expression in the lung tissue in lipopolysaccharide (LPS)-induced acute lung injury (ALI) rats. Thirty Sprague-Dawley (SD) rats were randomly assigned to control group, ALI group, and propofol postcondition group (each n=10). The model of ALI was reproduced by intravenous injection of LPS (8 mg/kg for 30 minutes) into the rats, equivalent normal saline was injected into the rats of control group. The rats were postconditioned with propofol injected intravenously by 20 mg/kg bolus dose and then continuously by 40 mg×kg(-1)×h(-1) with a constant speed for 1 hour. The rats were sacrificed 6 hours after drug injection. Lung wet/dry weight (W/D) ratio and lung permeability index (LPI) was taken. Tumor necrosis factor-α (TNF-α) level in bronchoalveolar lavage fluid (BALF) was detected using enzyme linked immunosorbent assay (ELISA) method and TLR4 mRNA expression in lung tissue was assessed by reverse transcription-polymerase chain reaction (RT-PCR). The lung W/D ratio, LPI, TLR4 mRNA and TNF-α in BALF were all increased in ALI group compared with control group [lung W/D ratio: 5.30±0.28 vs. 4.21±0.14, LPI (×10(-3)): 8.7±2.2 vs. 3.3±2.0, TLR4 mRNA: 2.451±0.028 vs. 0.998±0.021, TNF-α: 643.46±62.31 ng/L vs. 120.43±12.65 ng/L, all P<0.05]. The above indexes were significantly reduced in the propofol group than those in the ALI group [lung W/D ratio: 4.68±0.19 vs. 5.30±0.28, LPI (×10(-3)): 5.8±2.0 vs. 8.7±2.2, TLR4 mRNA: 1.126±0.025 vs. 2.451±0.028, TNF-α: 290.53±32.01 ng/L vs. 643.46±62.31 ng/L, all P<0.05], but still higher than those in control group (all P<0.05). Postconditioning with propofol may alleviate ALI via reducing TLR4 mRNA expression, and inhibit the waterfall-like inflammatory reaction.