Intraperitoneal Injection Of Zymosan Research Articles

Megakaryocyte NLRP3 hyperactivation induces mild anemia and potentiates inflammatory response in mice.

The NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome has been described in both immune cells and platelets, but its role in the megakaryocyte (MK) lineage remains elusive. The aim of this study was to explore the role of NLRP3 inflammasome in megakaryocytes and platelets. We generated Nlrp3 A350V/+/Gp1ba-CreKI/+ mice carrying a mutation genetically similar to the one observed in human Muckle-Wells syndrome, which leads to hyperactivity of NLRP3 specifically in MK and platelets. Platelets from the mutant mice expressed elevated levels of both precursor and active form of caspase-1, suggesting hyperactivity of NLRP3 inflammasome. Nlrp3 A350V/+/Gp1ba-CreKI/+ mice developed normally and had normal platelet counts. Expression of major platelet receptors, platelet aggregation, platelet deposition on collagen under shear, and deep vein thrombosis were unchanged. Nlrp3 A350V/+/Gp1ba-CreKI/+ mice had mild anemia, reduced Ter119+ cells in the bone marrow, and splenomegaly. A mild increase in MK TGF-β1 might be involved in the anemic phenotype. Intraperitoneal injection of zymosan in Nlrp3 A350V/+/Gp1ba-CreKI/+ mice induced increased neutrophil egression and elevated levels of a set of proinflammatory cytokines, alongside IL-10 and G-CSF, in the peritoneal fluid as compared with control animals. MK/platelet NLRP3 inflammasome promotes the acute inflammatory response and its hyperactivation in mice leads to mild anemia and increased extramedullary erythropoiesis.

Characterization and Hepatoprotections of Ganoderma lucidum Polysaccharides against Multiple Organ Dysfunction Syndrome in Mice.

Background The liver is one of the most commonly affected organs in multiple organ dysfunction syndrome (MODS). In recent years, there have been many studies on Ganoderma lucidum polysaccharides (GLP), but the role of GLP in MODS is still unclear. The purpose of this work was to explore the antioxidant, anti-inflammatory, and protective effects of GLP on the liver in MODS model mice. Methods The characteristic properties of GLP were processed by physicochemical analysis. The MODS models were successfully established with intraperitoneal injection of zymosan in Kunming strain mice. The antioxidant, anti-inflammatory, and hepatoprotective effects of GLP were processed both in vitro and in vivo by evaluating the oxidative parameters, inflammatory factors, and liver pathological observations. Results The characterization analysis revealed that GLP was a pyranose mainly composed of glucose with the molecular weights (Mw) of 8309 Da. The experimental results proved that GLP had potential hepatoprotection possibly by improving the antioxidant status (scavenging excessive oxygen radicals, increasing the antioxidant enzyme activities, and reducing the lipid peroxide), alleviating the inflammatory response (reducing the inflammatory factor levels), and guaranteeing the liver functions. Conclusions This research suggested that GLP had the potential to be developed as a natural medicine for the treatment of multiple organ failure.

Behavioral and physiological responses to intraperitoneal injection of zymosan in chicks

Zymosan is a cell wall component of the yeast Saccharomyces cerevisiae and produces severe inflammatory responses in mammals. When zymosan is peripherally injected in mammals, it induces several behavioral and physiological changes including anorexia and hyperthermia. However, to our knowledge, behavioral and physiological responses to zymosan have not yet been clarified in birds. Therefore, the purpose of the present study was to determine if intraperitoneal injection of zymosan affects food intake, voluntary activity, cloacal temperature, plasma corticosterone (CORT) and glucose concentrations, and splenic gene expression of cytokines in chicks (Gallus gallus). Intraperitoneal injection of zymosan (2.5 mg) significantly decreased food intake, voluntary activity, and plasma glucose concentration, and increased plasma CORT concentration. The injection of 0.5 mg zymosan significantly increased cloacal temperature, while 2.5 mg zymosan had a tendency to increase it. Finally, 2.5 mg zymosan significantly increased the splenic gene expression of interleukin-1β (IL-1β), IL-6, IL-8, interferon-γ, and tumor necrosis factor–like cytokine 1A. The present results suggest that zymosan would be one of components which induces nonspecific symptoms including anorexia, hypoactivity, hyperthermia, and stress responses, under fungus infection in chicks.

34: Hematopoietic Stem/Progenitor Cell Dependent Participation of Innate Lymphoid Cells in Low-Intensity Sterile Inflammation

Innate lymphoid cells (ILCs) are increasingly acknowledged as important mediators of immune homeostasis and pathology. They act as early orchestrators of immunity and as such they make up interesting therapeutic targets for several diseases and possibly a means to peripheral tolerance. Taking advantage of an animal model of sterile peritonitis, induced by intraperitoneal injection of zymosan, a fungal derived TLR-2 ligand we studied the progenitor–successor relationship between the hematopoietic stem/progenitor cells (HSPC) and ILCs at the site of sterile inflammation. Our results demonstrate that the strength of the inflammatory signal affects the capacity of BM-derived HSPCs to migrate and give rise in situ to ILCs. Both low- and high-dose of zymosan injections triggered the appearance of mature ILCs in the peritoneal cavity. Only in low-dose injected mice, the recovered ILCs seemed to be dependent on an in situ differentiation of BM-derived HSPCs and/or ILC2 precursors (ILC2P) wherein high-dose, the stronger inflammatory environment seemed to be able to induce the emergence of ILCs independently of BM-derived HSPCs. To further elucidate the importance of the inflammatory environment per se for the attraction of mature ILCs, an anti- inflammatory drug was used. Treatment of mice with alpha-1 anti-trypsin (AAT) 15 min after injection of either low- or high- dose of zymosan, led to the blockade of the migration of HSPCs into the peritoneal cavity resulting in a loss of even mature ILCs in mice injected with the low-dose of zymosan. Contrary, in mice injected with high-dose, progenitor cells of type 2 of ILCs could be still recovered, but not mature ILC2 cells. We suggest that the relationship between HSPCs and ILCs seem to be affected by the strength of the inflammatory stimuli and that the use of anti-inflammatory molecules like A1 antitrypsin may attenuate the inflammation and to some extent prevent the migration of HSCPs to the site of inflammation and the emergence of mature ILCs.

Impaired Peritoneal Macrophage Function and Delayed Neutrophil Recruitment are Secondary to a Leaky Gut in JAM‐A Deficient Mice

Junctional adhesion molecule‐A (JAM‐A) is a transmembrane glycoprotein expressed on leukocytes, endothelia and epithelia that regulates endothelial/epithelial barrier function as well as leukocyte transendothelial/transepithelial migration. While biological roles of JAM‐A have been extensively studied with JAM‐A knockout mice (Jam‐a KO), tissue‐specific JAM‐A deficient animals remain poorly documented. Therefore, we generated mice with tissue selective deletion of JAM‐A in myelomonocytic cells (LysM‐cre; Jam‐a fl/fl) and the intestinal epithelium (Villin‐cre; Jam‐a fl/fl). We then used an acute peritonitis model induced by intraperitoneal injection of zymosan or lipopolysaccharide (LPS) to study the role of tissue selective expression of JAM‐A in recruitment of polymorphonuclear neutrophils (PMN). Consistent with previous reports, infiltration of PMN into the peritoneum in response to zymosan or LPS was significantly reduced in Jam‐a KO versus Jam‐a WT mice. Surprisingly, in LysM‐cre; Jam‐a fl/fl, the number of PMN recruited into the peritoneum was not affected in response to zymosan nor LPS compared to control littermates, indicating that JAM‐A on PMN is not required for infiltration under such conditions. Importantly, intestinal epithelial‐selective loss of JAM‐A resulted in significant reduction of PMN infiltration in Villin‐cre; Jam‐a fl/fl mice, confirming that extrinsic factors, independent on JAM‐A expression on PMN are necessary for leukocyte recruitment to peritoneum under the conditions studied. We also observed that in response to zymosan or LPS, peritoneal macrophages from Jam‐a KO or Villin‐cre; Jam‐a fl/fl mice produced less of the chemokine CXCL1 and had reduced activity of the transcription factor NFkB. Conversely, peritoneal macrophages from LysM‐cre; Jam‐a fl/fl mice were unaffected compared to Jam‐a fl/fl mice. Given that loss of JAM‐A on intestinal epithelial cells resulted in increased intestinal permeability, we hypothesized that bacterial derived products may impair peritoneal macrophage function. Therefore, experiments were conducted with germ free Villin‐cre; Jam‐a fl/fl mice. We observed that macrophage responses as well as peritoneal recruitment of PMN in response to zymosan or LPS was not affected compared to control mice. These findings suggest that a leaky intestinal barrier and intestinal microbes are critical in regulating systemic neutrophil recruitment through effects on macrophage release of inflammatory mediators. Such observations highlight the functional link between the intestinal barrier, microbiota and the regulation of innate immune responses.Support or Funding InformationNIH grants 1R01DK097256 to TLD, DK59888, DK55679 to AN and DK072564, DK061379, and DK079392 to CP.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Nintedanib reduces pulmonary fibrosis in a model of rheumatoid arthritis-associated interstitial lung disease.

Rheumatoid arthritis (RA)-associated interstitial lung disease (RA-ILD) develops in ~20% of patients with RA. SKG mice, which are genetically prone to development of autoimmune arthritis, develop a pulmonary interstitial pneumonia that resembles human cellular and fibrotic nonspecific interstitial pneumonia. Nintedanib, a tyrosine kinase inhibitor approved for treatment of idiopathic pulmonary fibrosis, has been shown to reduce the decline in lung function. Therefore, we investigated the effect of nintedanib on development of pulmonary fibrosis and joint disease in female SKG mice with arthritis induced by intraperitoneal injection of zymosan (5 mg). Nintedanib (60 mg·kg-1·day-1 via oral gavage) was started 5 or 10 wk after injection of zymosan. Arthritis and lung fibrosis outcome measures were assessed after 6 wk of treatment with nintedanib. A significant reduction in lung collagen levels, determined by measuring hydroxyproline levels and staining for collagen, was observed after 6 wk in nintedanib-treated mice with established arthritis and lung disease. Early intervention with nintedanib significantly reduced development of arthritis based on joint assessment and high-resolution μ-CT. This study impacts the RA and ILD fields by facilitating identification of a therapeutic treatment that may improve both diseases. As this model replicates the characteristics of RA-ILD, the results may be translatable to the human disease.

Protective effects of dimethyl sulfoxide on zymosan-insulted gut barrier impairment

To explore the effect of dimethyl sulfoxide(DMSO) on suppressing the release of gut inflammatory cytokine and re-store of the barrier impairment following zymosan-insulted systemic inflammatory response syndrome (SIRS). S D rats were randomly divided into four groups:sham with administration of normal saline (SS group); sham with administration of DMSO (DS group); zymosan with administration of normal saline (ZS group); and zymosan with administration of DMSO (ZD group), each group includes two subgroups at 4 h and 24 h after surgery. At 4 h and 24 h after intraperitoneal injection of zymosan (750 mg/kg), the levels of intestinal inflammatory cytokines (tumor necrosis factor-αand interleukin-10) and the activity of diamine oxidase in plasma were examined. Intestinal injury was evaluated by using an intestinal histological score. DMSO suppressed the release of tumor necrosis factor-αand increased interleukin-10 levels in the intestine compared with the ZS group at the corresponding time points. DMSO decreased the level of diamine oxidase in plasma compared with the ZS group. DMSO restored the injury of intestinal villi and the gut injury score was significantly lower than that in the ZS group. DMSO can suppress the release of intestinal inflammatory cytokines and restore zymosan-insulted gut barrier impairment.

Dynamic weight bearing as a non-reflexive method for the measurement of abdominal pain in mice.

Chronic pelvic pain (CPP) is a high burden for patients and society. It affects 15-24% of women in reproductive age and is an area of high unmet medical need. CPP can be caused by a wide range of visceral diseases such as abdominal infections, gastrointestinal or gynaecological diseases like endometriosis. Despite the high medical need for this condition, pharmacological approaches are hampered by the limited number of available methods for the behavioural evaluation of pain in inflammation-driven animal models of pelvic pain. The dynamic weight bearing (DWB) system was used for the evaluation of spontaneous behaviour changes in the zymosan-induced peritonitis mouse model. Inflammatory mediator levels were evaluated in peritoneal lavage and their correlation with the behavioural endpoints was assessed. We evaluated the effect on behavioural endpoints of the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib and the Nav 1.8 blocker A-803467. The presence of a relief posture, characterized by a significantly increased weight distribution towards the front paws, was observed following intraperitoneal injection of zymosan. A positive correlation was detected between PGE2 levels in the peritoneal lavage and DWB endpoints. In addition, zymosan-induced weight bearing changes were reverted by celecoxib and A-803467. This study described for the first time the use of DWB as a non-subjective and non-reflexive method for the evaluation of inflammatory-driven abdominal pain in a mouse model.

HMGB1 Inhibition During Zymosan-Induced Inflammation: The Potential Therapeutic Action of Riboflavin.

Sepsis, also known as systemic inflammatory response syndrome, is a life-threatening condition caused by a pathogenic agent and leading to multiple organ dysfunction syndrome. One of the factors responsible for the excessive intensification of the inflammatory response in the course of inflammation is high-mobility group protein B1 (HMGB1). HMG-1 is a nuclear protein which, after being released to the intercellular space, has a highly pro-inflammatory effect and acts as a late mediator of lethal damage. The purpose of this study was to examine whether the anti-inflammatory action of riboflavin is accompanied by inhibition of HMGB1 release during peritoneal inflammation and zymosan stimulation of macrophages. Peritonitis was induced in male BALB/c and C57BL/6J mice via intraperitoneal injection of zymosan (40 mg/kg). RAW 264.7 macrophages were activated with zymosan (250 µg/ml). Riboflavin (mice, 50 mg/kg; RAW 264.7, 25 µg/ml) was administered 30 min before zymosan, simultaneously with, or 2, 4, 6 h after zymosan. Additionally, mRNA expression of HMGB1 and its intracellular and serum levels were evaluated. The research showed that riboflavin significantly reduces both the expression and the release of HMGB1; however, the effect of riboflavin was time-dependent. The greatest efficacy was found when riboflavin was given 30 min prior to zymosan, and also 2 and 4 h (C57BL/6J; RAW 264.7) or 4 and 6 h (BALB/c) after zymosan. Research showed that riboflavin influences the level of HMGB1 released in the course of inflammation; however, further study is necessary to determine its mechanisms of action.

Dimethyl sulfoxide inhibits zymosan-induced intestinal inflammation and barrier dysfunction.

To investigate whether dimethyl sulfoxide (DMSO) inhibits gut inflammation and barrier dysfunction following zymosan-induced systemic inflammatory response syndrome and multiple organ dysfunction syndrome. Sprague-Dawley rats were randomly divided into four groups: sham with administration of normal saline (SS group); sham with administration of DMSO (SD group); zymosan with administration of normal saline (ZS group); and zymosan with administration of DMSO (ZD group). Each group contained three subgroups according to 4 h, 8 h, and 24 h after surgery. At 4 h, 8 h, and 24 h after intraperitoneal injection of zymosan (750 mg/kg), the levels of intestinal inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-10] and oxides (myeloperoxidase, malonaldehyde, and superoxide dismutase) were examined. The levels of diamine oxidase (DAO) in plasma and intestinal mucosal blood flow (IMBF) were determined. Intestinal injury was also evaluated using an intestinal histological score and apoptosis of intestinal epithelial cells was determined by deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The intestinal epithelial tight junction protein, ZO-1, was observed by immunofluorescence. DMSO decreased TNF-α and increased IL-10 levels in the intestine compared with the ZS group at the corresponding time points. The activity of intestinal myeloperoxidase in the ZS group was higher than that in the ZD group 24 h after zymosan administration (P < 0.05). DMSO decreased the content of malondialdehyde (MDA) and increased the activity of superoxide dehydrogenase (SOD) 24 h after zymosan administration. The IMBF was lowest at 24 h and was 49.34% and 58.26% in the ZS group and ZD group, respectively (P < 0.05). DMSO alleviated injury in intestinal villi, and the gut injury score was significantly lower than the ZS group (3.6 ± 0.2 vs 4.2 ± 0.3, P < 0.05). DMSO decreased the level of DAO in plasma compared with the ZS group (65.1 ± 4.7 U/L vs 81.1 ± 5.0 U/L, P < 0.05). DMSO significantly preserved ZO-1 protein expression and localization 24 h after zymosan administration. The TUNEL analysis indicated that the number of apoptotic intestinal cells in the ZS group was much higher than the ZD group (P < 0.05). DMSO inhibited intestinal cytokines and protected against zymosan-induced gut barrier dysfunction.

Immunosuppression via adenosine receptor activation by adenosine monophosphate released from apoptotic cells

Apoptosis is coupled with recruitment of macrophages for engulfment of dead cells, and with compensatory proliferation of neighboring cells. Yet, this death process is silent, and it does not cause inflammation. The molecular mechanisms underlying anti-inflammatory nature of the apoptotic process remains poorly understood. In this study, we found that the culture supernatant of apoptotic cells activated the macrophages to express anti-inflammatory genes such as Nr4a and Thbs1. A high level of AMP accumulated in the apoptotic cell supernatant in a Pannexin1-dependent manner. A nucleotidase inhibitor and A2a adenosine receptor antagonist inhibited the apoptotic supernatant-induced gene expression, suggesting AMP was metabolized to adenosine by an ecto-5'-nucleotidase expressed on macrophages, to activate the macrophage A2a adenosine receptor. Intraperitoneal injection of zymosan into Adora2a- or Panx1-deficient mice produced high, sustained levels of inflammatory mediators in the peritoneal lavage. These results indicated that AMP from apoptotic cells suppresses inflammation as a 'calm down' signal. DOI: http://dx.doi.org/10.7554/eLife.02172.001.

Brief Report: Testosterone Is Protective in the Sexually Dimorphic Development of Arthritis and Lung Disease in SKG Mice

ObjectiveRheumatoid arthritis (RA) is a sexually dimorphic inflammatory autoimmune disease with both articular and extraarticular disease manifestations, including RA‐associated interstitial lung disease. Low levels of testosterone have been linked to disease severity in men with RA, and supplemental testosterone has been shown to improve RA symptoms in both postmenopausal women and men with low levels of testosterone. The mechanisms by which sex and sex steroids affect the immune system and autoimmunity are poorly understood. The purpose of this study was to examine the protective effects of testicular‐derived sex hormones on the development of joint and lung disease in an autoimmune mouse model.MethodsArthritis prevalence and severity were assessed in orchiectomized, sham‐orchiectomized, and intact male SKG mice as well as in female SKG mice over a 12‐week period after intraperitoneal injection of zymosan. Lung tissues were evaluated by quantifying cellular accumulation in bronchoalveolar lavage fluid, collagen levels, and histologic changes. An antigen microarray was used to evaluate autoantibody generation under each experimental condition.ResultsFemale SKG mice developed arthritis and lung disease at increased prevalence and severity as compared to intact male mice. The absence of testosterone after orchiectomy led to increased arthritis, lung disease, and autoantibody generation in orchiectomized male mice as compared to intact male mice.ConclusionSKG mice represent an authentic sexually dimorphic mouse model of both the joint and lung disease seen in humans with RA. Testosterone protects against the development of joint and lung disease in male SKG mice.

N-acetylcysteine Administration is Associated with Reduced Activation of NF-kB and Preserves Lung Dendritic Cells Function in a Zymosan-Induced Generalized Inflammation Model

In severe sepsis, functional impairment and decreased numbers of dendritic cells (DCs) are essential reasons for immune function paralysis, secondary organ infection, and organ failure. We investigated the effects of N-acetylcysteine (NAC) administration on protecting lung DCs function in a zymosan-induced generalized inflammation (ZIGI) model. ZIGI was initiated in 80 Balb/c mice by intraperitoneal injection of zymosan (ZYM; 900mg/kg). Mice were divided into 4 groups: (1) SHAM+Vehicle; (2) SHAM+NAC; (3) ZYM+Vehicle; and (4) ZYM+NAC. NAC (100mg/kg) was administered at different time after ZYM injection. After 48h, we assessed: lung tissue pathological changes; arterial blood gas values; purified lung DCs surface expressions of MHC-II/I-A(d) and co-stimulatory molecules CD80, CD83, and CD86; lung DCs mRNA levels of chemokine receptors CCR5 and CCR7; lung DCs apoptosis; lung DCs ultrastructure by transmission electron microscopy; lung DCs NF-kB transcription factor activity; and LPS-stimulated lung DCs in vitro production of IL-12 and IL-10 were examined. NAC treatment resulted in: significant improvements in ZYM-induced lung tissue damage and impaired lung function; inhibited lung DCs ZYM-induced increased expression of MHC-II/I-A(d), CD83, and CD86, but not CD80; reduced lung DCs ZYM-induced CCR5 and CCR7 mRNA levels; suppressed ZYM-induced lung DCs apoptosis; ameliorated ZYM-induced lung DCs ultrastructural abnormalities; inhibited ZYM-induced lung DCs NF-κB activity; and enhanced lung DCs production of IL-12 and inhibited their production of IL-10. Repeated injections of NAC during the early stage of severe sepsis effectively inhibited lung DCs activation and their apoptosis, which could preserve DCs function.

Strain-specific effects of riboflavin supplementation on zymosan-induced peritonitis in C57BL/6J, BALB/c and CBA mice

AimsWe investigated the effects of riboflavin (vitamin B2) on the kinetics of zymosan-induced peritonitis in three strains of mice. Main methodsPeritonitis was induced in males of C57BL/6J, BALB/c and CBA mice by intraperitoneal injection of zymosan (40mg/kg) or zymosan supplemented with riboflavin (50mg/kg). During the first 45min of inflammation the pain symptoms were scored. At the selected time points (4, 6, 8, 10, 24, and 30h) the mice were sacrificed and peritoneal exudates were retrieved. Leukocytes, among them polymorphonuclear cells (PMNs) and macrophages (Mac3+ cells) were counted. Levels of inducible nitric oxide synthase (iNOS) were measured in cell pellets while supernatants were used for measurements of nitric oxide, cytokine/chemokines (IL-6, IL-10, MCP-1, IFNγ, TNF-α, and IL-12p70), and matrix metalloproteinase-9 (MMP-9). Key findingA riboflavin ip injection induced pain symptoms itself, but reduced zymosan-induced pain in C57BL/6J and CBA strains of mice when coinjected with zymosan. In comparison with the mice injected with zymosan only, riboflavin coinjection prolonged inflammation in C57BL/6J mice due to prolonged macrophage accumulation; inhibited peritoneal leukocytes (PTL) accumulation in BALB/c due to inhibited influx of macrophages and PMNs; and inhibited PTL accumulation in CBA mice due to delayed PMN influx. These effects corresponded with the delayed (C57BL/6J) or inhibited (BALB/c and CBA) expression of iNOS in PTL lysates, and with the prolonged (C57BL/6) or inhibited (BALB/c) intraperitoneal accumulation of MMP-9. Moreover, cytokine accumulation was affected in a strain-specific way. SignificanceRiboflavin is antinociceptive during yeast-induced peritonitis, but its anti-inflammatory effects are strain-specific.

Inhibition of zymosan-induced kidney dysfunction by tyrphostin AG-490

BackgroundZymosan-induced shock has been associated with an increased production of pro-inflammatory cytokines and mediators, causing a generalized dysfunction of liver, lung and kidneys. Herein, we investigate the effects of tyrphostin AG-490 on the early inflammation and on the late renal injury provoked by zymosan injection.MethodsShock was induced by intraperitoneal injection of zymosan in a dose of 0.8–1.0 mg/g body weight in BALB/c mice and 0.8 mg/g body weight in SCID mice. Tyrphostin AG-490 was administered intraperitoneally in a dose of 5 mg/kg immediately after shock induction. Blood, peritoneal lavage and kidneys were collected at certain time points after zymosan injection. The levels of MIP-1α, RANTES, IL-6, IL-10, α1-antitrypsin and C5a in plasma were determined by ELISA. The number of IL-10-secreting cells in peritoneum was assayed by ELISPOT. Kidney function was monitored by measurement of urine/plasma creatinine levels and proteinuria. Histological assessment of renal injury was performed in a blinded fashion after hematoxylin/eosin staining. Immunohistochemistry analyses were used to evaluate the expression of C5aR, STAT1, STAT3 and the binding ability of IgGs in kidneys.ResultsTyrphostin AG-490 attenuated the early phase of zymosan-induced shock via inhibition of MIP-1α, RANTES and C5a plasma levels and via elevation of IL-10 in plasma. The drug increased IL-10 production in peritoneum and the number of IL-10-secreting peritoneal cells. AG-490 was able to retain the time of coagulation and the level of α1-antitrypsin to normal values. At the late stage of shock, AG-490 decreased scores of tubular injury, cell infiltration and glomerular lesions in parallel with diminished creatinine plasma level and protein excretion. These beneficial effects of AG-490 were related to lowered levels of circulating IL-6, MIP-1α and C5a, and to inhibited expression of STAT1, STAT3 and C5aR in kidneys. The drug diminished the production of zymosan-specific IgG antibodies and hindered the glomeruli from IgGs recognition.ConclusionTyrphostin AG-490 reduced the magnitude of the initial inflammatory response in zymosan-induced shock and prevented the development of severe kidney dysfunction. Our data suggest that the drug might be used as a therapeutic approach in cases where shock is combined with acute renal injury.

Innovative technique for the study of pneumoperitoneum in the evaluation of abdominal pain after chemical irritation with zymozan

To assess the influence of pneumoperitoneum in mice submitted to peritoneal irritation provoked by the biological agent Saccharomyces cerevisae, by counting the number of abdominal contractions elicited. To study the effects of pneumoperitoneum analgesic action, 60 mice were divided into two groups: the experimental group, subjected to pneumoperitoneum; and the control group, without pneumoperitoneum. The both groups received intraperitoneal injection of zymosan at a dose of 1mg/0,2ml/mouse. The sum of the number of abdominal contractions of the experimental group (with pneumoperitoneum) was significantly lower than that of the control group (without pneumoperitoneum). In the experimental group, a lower number of contractions occurred in each min compared to the control. The observation of the analgesic effect of pneumoperitoneum using CO2 in mice submitted to peritoneal irritation by zymosan was verified.

Differential modulation of lipopolysaccharide- and zymosan-induced hypophagia by dexamethasone treatment

The treatment of experimental animals with lipopolysaccharide (LPS) induces behavioral depression, in which the central and peripheral inductions of proinflammatory cytokines are proposed to play an important role. We have shown that the intraperitoneal injection of zymosan, composed of insoluble particles prepared from yeast cell walls, can induce behavioral depression assessed as hypophagia in mice, although the role of proinflammatory cytokines in this response has not yet been investigated. We have also shown that the subcutaneous injection of the corticoid, dexamethasone (Dex), a potent inhibitor of cytokine production, is effective in attenuating hypophagia in LPS-treated mice. The attenuated response was associated with the suppression of the gene induction of proinflammatory cytokines (i.e., IL-1β, IL-6 and TNFα) in the brain and liver. In contrast, no significant induction of proinflammatory cytokine genes was observed in the brain or liver during zymosan-induced hypophagia; the subcutaneous injection of Dex did not attenuate zymosan-induced hypophagia but its intraperitoneal injection did. Thus, zymosan-induced hypophagia was less responsive to a subcutaneous injection of dexamethasone than LPS-induced hypophagia, which may be due to the limited role of systemic inflammation in this response. An important role of localized, rather than systemic, inflammation in zymosan-induced hypophagia was suggested, although the role of local proinflammatory cytokines remains to be clarified.

Lipid synthesis in macrophages during inflammation in vivo: Effect of agonists of peroxisome proliferator activated receptors α and γ and of retinoid X receptors

The effects of peroxisome proliferator activated receptors alpha and gamma (PPAR-alpha and PPAR-gamma) and retinoid X receptor (RXR) agonists upon synthesis and accumulation of lipids in murine C57Bl macrophages during inflammation induced by injection of zymosan and Escherichia coli lipopolysaccharide (LPS) have been studied. It is significant that intraperitoneal injection of zymosan (50 mg/kg) or LPS (0.1 mg/kg) in mice led to a dramatic increase of [14C]oleate incorporation into cholesteryl esters and triglycerides and [14C]acetate incorporation into cholesterol and fatty acids in peritoneal macrophages. Lipid synthesis reached its maximum rate 18-24 h after injection and was decreased 5-7 days later to control level after LPS injection or was still heightened after zymosan injection. In macrophages obtained in acute phase of inflammation (24 h), degradation of 125I-labeled native low density lipoprotein (NLDL) was 4-fold increased and degradation of 125I-labeled acetylated LDL (AcLDL) was 2-3-fold decreased. Addition of NLDL (50 microg/ml) or AcLDL (25 microg/ml) into the incubation medium of activated macrophages induced 9-14- and 1.25-fold increase of cholesteryl ester synthesis, respectively, compared with control. Addition of NLDL and AcLDL into the incubation medium completely inhibited cholesterol synthesis in control macrophages but had only slightly effect on cholesterol synthesis in activated macrophages. Injection of RXR, PPAR-alpha, or PPAR-gamma agonists--9-cis-retinoic acid (5 mg/kg), bezafibrate (10 mg/kg), or rosiglitazone (10 mg/kg), respectively--30 min before zymosan or LPS injection led to significant decrease of lipid synthesis. Ten hour preincubation of activated in vivo macrophages with the abovementioned agonists (5 microM) decreased cholesteryl ester synthesis induced by NLDL and AcLDL addition into the cell cultivation medium. The data suggest that RXR, PPAR-alpha, or PPAR-gamma agonists inhibited lipid synthesis and induction of cholesteryl ester synthesis in inflammatory macrophages caused by capture of native or modified LDL.

Agonists of PPAR-α, PPAR-γ, and RXR inhibit the formation of foam cells from macrophages in mice with inflammation

We studied the effect of agonists of peroxisome proliferator-activated receptors alpha and gamma and retinoid X receptors on the concentration and synthesis of lipids in macrophages of C57B1/6 mice with inflammation induced by intraperitoneal injection of zymosan. We revealed a significant increase in [1-14C]oleate incorporation into cholesterol esters and triglycerides, increase in the content of free cholesterol, cholesterol esters, and triglycerides, and formation of oil red-stained lipid inclusions in peritoneal macrophages 24 h after administration of zymosan in a dose of 50 mg/kg. Treatment with agonists of retinoid X receptors and peroxisome proliferator-activated receptors alpha and gamma 30 min before and 12 h after zymosan injection decreased the synthesis of triglycerides and cholesterol esters, reduced the content of free cholesterol, cholesterol esters, and triglycerides in macrophages, and prevented the formation of cytoplasmic lipid inclusions in macrophage-derived foam cells during inflammation.

Pulmonary Responses to Overventilation in Late Multiple Organ Failure

Patients with multiple organ failure (MOF) require mechanical ventilation for several days. The enormous significance of the ventilation strategy for the outcome of these patients is well appreciated. However, most studies have focused on the onset and the early phase of MOF. It was the aim of the current study to investigate the effect of ventilation in the course of MOF. Using a model where mice develop MOF 7-14 days after intraperitoneal injection of zymosan, the authors analyzed lung functions, signaling pathways, and mediator release in response to protective ventilation (end-expiratory pressure -3 cm H2O; end-inspiratory pressure -10 cm H2O) and overventilation (-22.5 cm H2O) in isolated lungs ex vivo. On day 7, pulmonary compliance, pulmonary resistance, and tidal volume were normal, but vascular resistance was elevated compared with untreated animals. During ex vivo ventilation, these lungs showed enhanced nuclear factor-kappaB activation, Akt kinase phosphorylation, and cytokine release, and this was further aggravated by overventilation. After 14 days, zymosan-treated animals were characterized by pulmonary hypertension, reduced tidal volume, elevated pulmonary resistance, and increased mediator production. However, in these lungs, neither nuclear factor-kappaB activation nor cytokine production where enhanced by overventilation. The zymosan model is characterized by pulmonary inflammation, diminished lung functions, and chronic hypertension. Mechanical ventilation with high distending pressures further augmented cytokine production in this chronic model of MOF only if it significantly augmented tidal volume. The authors speculate that these findings may be explained on the basis of different degrees of lung stretch.