Administration Of Zymosan Research Articles

Panax notoginseng Saponins Attenuate Atherogenesis Accelerated by Zymosan in Rabbits

Panax notoginseng saponins (PNS) are highly valued traditional Chinese medicine. The effects of PNS (120 mg/kg, once daily administrated intragastrically (i.g.)) on atherosclerosis induced by a high-cholesterol diet and chronic inflammation, which was derived through zymosan (10 mg/kg, once every 2 d) administration intraperitoneally, were evaluated in rabbits for 8 weeks. A normal group, a simple high-fat diet group, and a zymosan plus high-cholesterol diet group (Zym) were used as controls. Typical pathologic changes associated with atherosclerosis in rabbits following induction by zymosan were alleviated by PNS treatment. After 2, 4, 6, and 8 weeks of treatment, PNS decreased the serum levels of total cholesterol, triglyceride, low-density lipoprotein cholesterol, interleukin-6 and C-reactive protein as well as increased high-density lipoprotein cholesterol level significantly in comparison with those in the Zym group, except for triglycerides at week 2. In addition, PNS treatment significantly decreased the mRNA expression levels of monocyte chemoattactant protein-1 and nuclear factor-kappaB/p65 in the aorta wall after 8 weeks of treatment compared with the Zym group. In conclusion, PNS attenuates atherogenesis through an antiinflammatory action and regulation of the blood lipid profile.

The acute phase response stimulates the expression of angiopoietin like protein 4

The acute phase response is characterized by elevations in serum triglyceride levels due to both an increase in hepatic VLDL production and a delay in the clearance of triglyceride rich lipoproteins secondary to a decrease in lipoprotein lipase (LPL) activity. Recently there has been a marked increase in our understanding of factors that regulate LPL activity. GPIHBP1 facilitates the interaction of LPL and lipoproteins thereby allowing lipolysis to occur. Angiopoietin like proteins (ANGPTL) 3 and 4 inhibit LPL activity. In the present study, treatment of mice with LPS, an activator of TLR4 and a model of Gram-negative infections, did not alter the expression of GPIHBP1 in heart or adipose tissue. However, LPS decreased the expression of ANGPTL3 in liver and increased the expression of ANGPTL4 in heart, muscle, and adipose tissue. Serum ANGPTL4 protein levels were markedly increased at 8 and 16 h following LPS treatment. Administration of zymosan, an activator of TLR2 and a model of fungal infections, also increased serum ANGPTL4 protein and mRNA levels in liver, heart, muscle, and adipose tissue. Finally, treatment of 3T3-L1 adipocytes with LPS or cytokines (TNF alpha, IL-1 beta, and interferon gamma) stimulated ANGPTL4 expression. These studies demonstrate that ANGPTL4 is a positive acute phase protein and the increase in ANGPTL4 could contribute to the hypertriglyceridemia that characteristically occurs during the acute phase response by inhibiting LPL activity.

PD98059, a specific MAP kinase inhibitor, attenuates multiple organ dysfunction syndrome/failure (MODS) induced by zymosan in mice

PD98059 (MEK1 Inhibitor) has been shown to act in vivo as a highly selective inhibitor of MEK1 activation and the MAP kinase cascade. In the present study, we have investigated the effects of PD98059, on the development of non-septic shock caused by zymosan in mice. Mice received either intraperitoneally zymosan (500 mg/kg, administered i.p. as a suspension in saline) or vehicle (0.25 ml/mouse saline). PD98059 (10 mg/kg) was administered 1 and 6 h after zymosan administration i.p. Organ failure and systemic inflammation in mice was assessed 18 h after administration of zymosan and/or PD98059. Treatment of mice with PD98059 attenuated the peritoneal exudation and the migration of polymorphonuclear cells caused by zymosan. PD98059 also attenuated the lung, liver and pancreatic injury and renal dysfunction caused by zymosan as well as the increase of TNF-α and IL-1β plasma levels caused by zymosan. Immunohistochemical analysis for inducible nitric oxide synthase (iNOS), nitrotyrosine, poly(ADP-ribose) (PAR), ICAM-1, P-selectin, Bax, Bcl-2 and FAS-ligand revealed positive staining in pancreatic and intestinal tissue obtained from zymosan-injected mice. The degree of staining for nitrotyrosine, iNOS, PAR, ICAM-1, P-selectin, Bax, Bcl-2 and FAS-ligand were markedly reduced in tissue sections obtained from zymosan-injected mice, which had received PD98059. Moreover treatment of mice with PD98059 (10 mg/kg) attenuated the NF-κB activation and mitogen-activated protein kinases (MAPK) expression induced by zymosan injection. In addition, administration of zymosan caused a severe illness in the mice characterized by a systemic toxicity, significant loss of body weight and a 60% of mortality at the end of observation period. Treatment with PD98059 significantly reduced the development of systemic toxicity, the loss in body weight and the mortality (20%) caused by zymosan. This study provides evidence that PD98059 attenuates the degree of zymosan-induced non-septic shock in mice.

Enhanced production of IL-17A during zymosan-induced peritonitis in obese mice

IL-17A is a proinflammatory cytokine critical for host defense and involved in the pathogenesis of autoimmune disorders. Obesity is associated with chronic low-grade inflammation but also with a heightened acute inflammatory response. We investigated the effect of obesity on IL-17A production using the model of ZY-induced peritonitis. Compared with lean controls, administration of ZY induced a significantly exacerbated inflammatory response in obese leptin-deficient ob/ob mice and in mice with diet-induced obesity (DIO). Levels of IL-17A in the peritoneal fluid in response to ZY were elevated significantly in ob/ob and DIO mice compared with lean animals. Reconstitution of ob/ob mice with exogenous leptin did not alter production of IL-17A significantly in response to ZY. Peritoneal cells and adipose tissue obtained from ZY-injected obese mice expressed significantly higher levels of IL-17A mRNA compared with lean mice. Approximately 2% of peritoneal Ly6G(+) neutrophils from ZY-injected obese mice expressed IL-17A protein, compared with 0.2% of cells obtained from lean mice. Neutralization of IL-17 in ob/ob mice inhibited neutrophil recruitment and production of neutrophil-attracting CXC chemokines and IL-6, without affecting macrophage infiltration or levels of IL-10 and the chemokine CCL2. In contrast, neutralization of IL-6 did not affect production of IL-17A or chemokines while reducing production of the acute-phase protein serum amyloid A significantly. These data demonstrate that neutrophil-derived IL-17A is increased in obese mice during acute inflammation and contributes to exacerbation of inflammatory responses.

The Effects of L-NG-Nitroarginine in a Zymosan-Induced Multiple Organ Dysfunction Syndrome Model

Background: The aim of this study was to investigate the role of nitric oxide in mesenteric ischemia, organ injury and survival in zymosan-induced multiple organ dysfunction syndrome (MODS) by using the nonselective nitric oxide synthase inhibitor L-N^G-nitroarginine (L-NNA). Methods: Swiss albino mice (20–40 g) were used in the study. The animals were randomly divided into four groups. The first group was treated intraperitoneally with saline and served as the sham group for L-NNA. The second group was treated with zymosan (500 mg/kg). The mice in the third and fourth group received L-NNA (20 mg/kg), 1 and 6 h after saline or zymosan administration. Six hours after the administration of zymosan, animals were used for mesenteric arterial blood flow (MABF) measurements and then sacrificed for biochemical and histopathological analyses at the 18th hour. Results: In zymosan-treated animals, MABF was significantly lower than that of solvent saline-treated controls (controls: 4.7 ± 0.8 ml·min^–1; zymosan: 1.7 ± 0.7 ml·min^–1, p < 0.05). L-NNA did not prevent zymosan-induced MABF decrease (controls: 4.5 ± 0.8 ml·min^–1; zymosan: 2.5 ± 1.4 ml·min^–1, p <0.05). Also treatment with L-NNA has no beneficial effect on survival and organ injury in zymosan-induced MODS. Conclusion: In this study, inhibition of both inducible and constitutive nitric oxide synthase by L-NNA did not abolish the harmful effects of zymosan. L-NNA remains an agent without any therapeutic potential in this acute experimental model of MODS.

Zymosan, but Not Lipopolysaccharide, Triggers Severe and Progressive Peritoneal Injury Accompanied by Complement Activation in a Rat Peritonitis Model

Fungal peritonitis is an important complication in peritoneal dialysis patients; either continuous or recurrent peritonitis may enhance peritoneal damage. Even when the peritoneal dialysis catheter is removed in patients with fungal peritonitis, peritoneal fibrosis can progress and evolve into encapsular peritoneal sclerosis. It is unclear why fungal infections are worse than bacterial in these respects. Zymosan is a cell wall component of yeast that strongly activates the complement system. In this study, we compared the effects of zymosan and bacterial LPS on peritoneal inflammation in a rat peritoneal injury model induced by mechanical scraping. Intraperitoneal administration of zymosan, but not LPS or vehicle, caused markedly enhanced peritonitis with massive infiltration of cells and deposition of complement activation products C3b and membrane attack complex on day 5. In rats administered zymosan and sacrificed on days 18 or 36, peritoneal inflammation persisted with accumulation of ED-1-positive cells, small deposits of C3b and membrane attack complex, exudation of fibrinogen, and capillary proliferation in subperitoneal tissues. When zymosan was administered daily for 5 days after peritoneal scrape, there was even greater peritoneal inflammation with peritoneal thickening, inflammatory cell accumulation, and complement deposition. Inhibition of systemic complement by pretreatment with cobra venom factor or local inhibition by i.p. administration of the recombinant complement regulator Crry-Ig reduced peritoneal inflammation in zymosan-treated rats. Our results show that yeast components augment inflammation in the injured peritoneum by causing complement activation within the peritoneal cavity. Local anticomplement therapy may therefore protect from peritoneal damage during fungal infection of the peritoneum.

FUMONISIN B1 REDUCES THE DEVELOPMENT OF MULTIPLE ORGAN FAILURE INDUCED BY ZYMOSAN IN MICE

Ceramide is a major proapoptotic mediator released in response to numerous stimuli, including oxidative stress and cytokines. The role of ceramide in the pathophysiology of inflammation is just emerging, and the potential relevance of this pathway in nonseptic shock is not known. The aim of this study was to investigate the effects of fumonisin B1 (FB1), a specific inhibitor of ceramide synthase, on the development of nonseptic shock in mice caused by zymosan. CD1 mice received either zymosan (500 mg/kg, administered i.p. as a suspension in saline) or vehicle (0.25 mL per mouse saline). Fumonisin B1 (3 mg/kg, i.p.) was administered 1 and 6 h after zymosan administration. Organ failure and systemic inflammation in mice were assessed 18 h after administration of zymosan and/or FB1. Treatment of mice with FB1 attenuated peritoneal exudate formation and the migration of polymorphonuclear cells caused by zymosan. Fumonisin B1 also attenuated plasma markers of lung, liver and pancreatic injury, and renal dysfunction caused by zymosan and the increase in myeloperoxidase activity in the intestine caused by zymosan. Immunohistochemical analyses for the presence of ceramide and nitrotyrosine revealed positive staining in intestinal tissue obtained from zymosan-injected mice. The degree of staining for ceramide and nitrotyrosine was markedly reduced in tissue sections obtained from zymosan-injected mice that had received FB1. In addition, administration of zymosan caused a severe illness in the mice characterized by a systemic toxicity, significant loss of body weight, and 80% mortality within 12 days. Treatment with FB1 significantly reduced systemic toxicity, weight loss, and mortality caused by zymosan. This study provides evidence that FB1 attenuates the degree of zymosan-induced nonseptic shock in mice.

Ethyl pyruvate reduces the development of zymosan-induced generalized inflammation in mice

Ethyl pyruvate (EP) is a simple aliphatic ester, which has been shown to have anti-inflammatory effects in previous numerous cell culture and animal studies. In the present study, we investigated the effects of EP (75 mg/kg i.p.) on the development of shock caused by zymosan. Prospective, randomized study. University-based research laboratory. Male CD mice. Mice received either intraperitoneally zymosan (500 mg/kg, administered i.p. as a suspension in saline) or vehicle (0.25 mL/mouse saline). EP (75 mg/kg i.p. was administered 1 and 6 hrs after zymosan administration. Organ failure and systemic inflammation in mice was assessed 18 hrs after administration of zymosan and/or EP. Treatment of mice with EP attenuated the peritoneal exudation and the migration of polymorphonuclear cells caused by zymosan. EP also attenuated the lung, liver, and pancreatic injury and renal dysfunction caused by zymosan as well as the increase in myeloperoxidase activity in the lung and intestine caused by zymosan. Immunohistochemical analysis for inducible nitric oxide synthase, nitrotyrosine, poly (ADP-ribose), tumor necrosis factor-alpha, and interleukin-1beta revealed positive staining in pancreatic and intestinal tissue obtained from zymosan-injected mice. The degree of staining for nitrotyrosine, inducible nitric oxide synthase, poly (ADP-ribose), tumor necrosis factor-alpha, and interleukin-1beta were markedly reduced in tissue sections obtained from zymosan-injected mice, which had received EP. In addition, administration of zymosan caused a severe illness in the mice characterized by a systemic toxicity, significant loss of body weight, and a 60% of mortality at the end of observation period (7 days). Treatment with EP significantly reduced the development of systemic toxicity, the loss in body weight, and the mortality (20%) caused by zymosan. This study provides evidence that EP attenuates the degree of zymosan-induced shock in mice.

Arrest of oogenesis in the bug Rhodnius prolixus challenged with the fungus Aspergillus niger is mediated by immune response-derived PGE 2

In this work we characterized the immune response of the insect Rhodnius prolixus to a direct injection into the hemocoel of the non-entomopathogenic fungus Aspergillus niger, and evaluated its consequences on host oogenesis. These animals were able to respond by mounting effective cellular and humoral responses to this fungus; these responses were shown, however, to have reproductive fitness costs, as the number of eggs laid per female was significantly reduced. The disturbance of egg formation during infectious process correlated with an elevation in the titer of hemolymph prostaglandin E 2 48 h post-challenge. Administration of Zymosan A as an immunogenic non-infectious challenge produced similar effects on phenoloxidase and prophenoloxidase activities, oocyte development and prostaglandin E 2 titer, precluding the hypothesis of an effect mediated by fungal metabolites in animals challenged with fungus. Ovaries at 48 h post-challenge showed absence of vitellogenic ovarian follicles, and the in vivo administration of prostaglandin E 2 or its receptor agonist misoprostol, partially reproduced this phenotype. Together these data led us to hypothesize that immune-derived prostaglandin E 2 raised from the insect response to the fungal challenge is involved in disturbing follicle development, contributing to a reduction in host reproductive output and acting as a host-derived adaptive effector to infection.

Novel Observation That Mice Lacking the Fifth Complement Cascade Protein Component (C5) Are Very Poor Stem Cell Mobilizers Explained by Defective Egress of Granulocytes: A Novel Role for Bone Marrow Granulocytes to Act as “ice Breaker” Cells in Facilitating Egress of Hematopoietic Stem/Progenitor Cells

We reported that complement cascade (CC) becomes activated in bone marrow (BM) during mobilization of hematopoietic stem/progenitor cells (HSPCs) by immunoglobulin (Ig)-dependent pathway and/or by alternative Ig-independent pathway and, as result of this, several potent bioactive CC anaphylatoxins (C3a, desArgC3a, C5a and desArgC5a) are released (Blood 2003; 101,3784; Blood 2004; 103,2071; Blood 2005; 105,40). Bioactive CC anaphylatoxins (C5a and desArgC5a) are also potent chemoattractants of granulocytes that bind to G-protein-coupled, seven trans-membrane span C5a receptors (C5aR and C5L2) on these cells. To learn more on the role of C5 cleavage fragments in HSPC mobilization, we studied mobilization in C5−/− and C5aR−/− mice as well as their normal wildtype littermates. Mobilization was induced by granulocyte colony-stimulating factor (G-CSF; high 250 μg/kg/6 days and low dose 50 μg/kg/6 days) or zymosan (20 mg/1kg/1 hour), which activate classical and alternative pathways of CC, respectively. We evaluated mobilization efficiency by counting the number of SKL cells, colony-forming unit granulocyte-macrophages (CFU-GMs), and white blood cells circulating in peripheral blood. In parallel, we employed transmission electron microscopy (TEM) to study the morphology and integrity of BM vessels in the BM-blood barrier. Activation of CC was measured by ELISA for C3 cleavage fragments and by histochemical staining for membrane attack-complex (MAC) depositions in BM tissue. We found by ELISA and histochemistry that CC activation correlates with the level of HSPC mobilization in wildtype mice and that mobilization of HSPCs was always preceded by the release of granulocytes from BM. Thus, granulocytes are the first wave of cells that increase in number during mobilization in peripheral blood. Mobilization studies in C5−/− revealed that these animals are very poor mobilizers. TEM studies demonstrated that hematopoietic cells together with granulocytes accumulated around small vessels in the BM of C5−/− animals, but they did not migrate or cross the BM-endothelial barrier. Since C5 cleavage fragments C5a and desArgC5a are potent chemoatrractants for granulocytes but not HSPCs, we hypothesize that a lack of both these anaphylatoxins in C5−/− animals prevents egress of granulocytes from BM, which always precedes egress of HSPCs. Furthermore, in C5aR−/−, mice mobilization was normal after administration of a high optimal dose of G-CSF. However, mobilization was significantly lower after a suboptimal dose of G-CSF or administration of zymosan. This indicates that another alternative receptor for C5a and desArgC5a (C5L2) may compensate for C5aR deficiency and that it plays a role in the egress of granulocytes from the BM as well. Thus, this study demonstrates that cells from the granulocytic lineage are actively involved in mobilization in a C5a,-desArgC5a-C5aR manner not only by secreting proteases that create a proteoytic environment in BM, but also as a kind of “ice-breaker” type cells necessary for disintegration of the endothelial-BM barrier to enable HSPCs to egress from the BM microenvironment. In cases of granulocytopenia or if granulocytes are not mobilized as seen in C5−/− mutants, mobilization of HSPCs is very poor. Thus, modulation of CC activation in the BM and stimulation of granulocyte egress from the BM into circulation may help to develop more efficient strategies for HSPC mobilization.

Tyrphostin AG-490 inhibited the acute phase of zymosan-induced inflammation

Tyrphostins, derivatives of benzylidene malononitrile are recognized as tyrosine kinase inhibitors that have been applied in some models of acute inflammatory conditions, like LPS and zymosan-induced shock. In the present study, we have investigated the effects of tyrphostin AG-490, on the development of multiple organ failure induced by i.p. injection of zymosan (1 mg/g body weight) in mice. Organ dysfunction and systemic inflammation was estimated 24 h after zymosan administration. Treatment of mice with AG-490 (dose, 5 mg/kg i.p. simultaneously with zymosan) decreased the number of cells and the level of NO in the peritoneal lavage. The substance attenuated the elevation of creatinine (indicator of renal failure), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and bilirubin (indicators for liver dysfunction) and prevented the accelerated coagulation time. The injection of zymosan resulted in a substantial increase in the serum level of TNF-α and IL-6, which was strongly inhibited by AG-490. Tyrphostin abolished the expression of iNOS and TNF-αR in the liver. Moreover, immunohistochemistry of liver showed decreased phosphorylation of Stat1 and Stat3. In conclusion, the administration of tyrphostin AG-490 in zymosan-induced nonseptic shock significantly improved the rate of survival and lead to less exerted signs of multiple organ failure.

Serotonergic and noradrenergic facilitation of the visceromotor reflex evoked by urinary bladder distension in rats with inflamed bladders

Bladder inflammation resulting from intravesical administration of zymosan significantly enhances the visceromotor reflex (VMR) evoked by urinary bladder distension (UBD). The present study examined whether intrathecal (i.t.) administration of receptor antagonists to either norepinephrine (NE) or serotonin (5-HT) altered this enhancement effect. I.t. administration of the non-specific 5-HT receptor antagonist methysergide (30 microg), the 5-HT(3) receptor antagonist ondansetron, or the 5-HT(1A) receptor antagonist WAY 100635 eliminated the enhancement effect produced by intravesical zymosan and also tended to reduce electromyographic (EMG) responses to UBD in non-inflamed rats. I.t. administration of either the non-specific NE receptor antagonist phentolamine (30 microg) or the alpha(1) antagonist WB 4101 also eliminated the enhancement effect, whereas i.t. administration of the alpha(2) antagonist yohimbine failed to significantly affect the enhancement effect. The effects of phentolamine and methysergide were not mediated by changes in bladder compliance. This is the first study to demonstrate that bladder hypersensitivity resulting from bladder inflammation is partly mediated by 5-HT and NE facilitatory effects. Based on these and previous findings we conclude that the net nociceptive response to bladder distension under conditions of bladder inflammation represents a complex interaction of facilitatory influences of spinal 5-HT and NE, and inhibitory influences of spinal opioids.

Adenosine Receptor Agonists Modulate Visceral Hyperalgesia in the Rat

Adenosine is an endogenous modulator of nociception. Its role in visceral nociception, particularly in visceral hyperalgesia, has not been studied. The aim of this study was to determine the effects of adenosine receptor agonists in a model of visceral hyperalgesia. The visceromotor response (VMR) in rats to colorectal distension (CRD; 80 mmHg, 20 seconds) was quantified by electromyographic recordings from the abdominal musculature. Three hours after the intracolonic administration of zymosan (25 mg/mL, 1 mL), VMRs to CRD were measured before and after either subcutaneous or intrathecal administration of an adenosine receptor agonist. Subcutaneous injection of 5'-N-ethylcarboxyamidoadenosine (NECA; an A1 and A2 receptor agonist), R(-)-N6-(2-phenylisopropyl)-adenosine (R-PIA; a selective A1 receptor agonist), or CGS-21680 hydrochloride (a selective A2a receptor agonist) dose-dependently (10-100 mg/kg) attenuated the VMR to CRD, although hindlimb weakness occurred at the higher doses tested. Intrathecal administration of NECA or R-PIA dose-dependently (0.1-1.0 microg/kg) decreased the VMR, whereas CGS-21680 hydrochloride was ineffective over the same concentration range. Higher intrathecal doses of the A1/A2 receptor agonist NECA produced motor weakness. Adenosine receptor agonists are antihyperalgesic, but also produce motor weakness at high doses. However, activation of the spinal A1 receptor significantly attenuates the VMR to CRD without producing motor weakness.

Role and Regulation of Adipokines during Zymosan-Induced Peritoneal Inflammation in Mice

Adipokines, cytokines mainly produced by adipocytes, are active participants in the regulation of inflammation. Administration of zymosan (ZY) was used to investigate the regulation and role of adipokines during peritonitis in mice. Injection of ZY led to a significant increase in leptin levels in both serum and peritoneal lavage fluid, whereas a differential trend in local vs. systemic levels was observed for both resistin and adiponectin. The role of leptin in ZY-induced peritonitis was investigated using leptin-deficient ob/ob mice, with and without reconstitution with exogenous leptin. Leptin deficiency was associated with delayed resolution of peritoneal inflammation induced by ZY, because ob/ob mice had a more pronounced cellular infiltrate in the peritoneum as well as higher and prolonged local and systemic levels of IL-6, TNFalpha, IL-10, and chemokine (C-X-C motif) ligand 2 compared with wild-type mice. Reconstitution with exogenous leptin exacerbated the inflammatory infiltrate and systemic IL-6 levels in ob/ob mice while inhibiting production of TNFalpha, IL-10, and chemokine (C-X-C motif) ligand 2. In contrast with the important role of leptin in regulating each aspect of ZY-induced peritonitis, adiponectin deficiency was associated only with a decreased inflammatory infiltrate, without affecting cytokine levels. These findings point to a complex role for adipokines in ZY-induced peritonitis and further emphasize the interplay between obesity and inflammation.

The Persistent Sciatic Inflammatory Neuropathy (SIN) Rat Model of Neuropathic Pain Does Not Involve Small-Fiber Axon Damage

Most neuropathic pain conditions are caused by damage to peripheral nociceptive neurons known as “small-fibers.” Examination of punch skin biopsies immunolabeled with pan-axonal markers has identified degeneration of distal nociceptive axons as a pathological hallmark of most neuralgias including numerous polyneuropathies, postherpetic neuralgia, and complex regional pain syndrome. Similar axonopathy is present in several rodent models of neuralgia (chronic constriction injury and spared nerve injury). Here we have measured the density of distal cutaneous small-fiber axons in rats with persistent mechanical allodynia caused by the sciatic inflammatory neuropathy (SIN), a model of painful neuritis. We have evaluated whether perineural immune activation sufficient to cause evoked-pain behaviors is also associated with loss of distal epidermal innervation.SIN was created in adult male Sprague-Dawley rats by perineural zymosan administration using established methods. Unoperated rats provided controls. Two weeks of sensory testing established the presence of static mechanical allodynia. Full-thickness punches were then collected from ipsilesional sural-innervated plantar hindpaw skin. These were immunolabeled against PGP9.5 using standard methods, and the density of epidermal neurites quantitated microscopically by a single examiner who was unaware of rats' experimental group. Neurite densities were similar in SIN and control samples (P = 0.96), suggesting that mechanical allodynia can occur from inflammation near a nerve, without distal small-fiber degeneration.

Absence of endogenous interleukin-10 enhanced organ dysfunction and mortality associated to zymosan-induced multiple organ dysfunction syndrome

Experimental evidence suggests that interleukin (IL)-10 plays a pivotal role in generalized inflammation. Here we investigate the effects of IL-10 gene deletion on the acute phase of the multiple organ dysfunction syndrome (MODS) caused by zymosan in the mouse. MODS was induced by zymosan administration (500 mg/kg, suspended in saline solution, i.p.) in IL-10 wild-type and knockout mice; sham groups were treated with vehicle. Mice were sacrificed 18 h after zymosan or saline administration. In another set of experiments, animals were monitored for 12 days to assess systemic toxicity and survival rate. Mice lacking IL-10 displayed increased peritoneal exudate volume and leukocytes. Also, we observed a significant increase in myeloperoxidase activity and lipid peroxidation in ileum and lung tissues, as well as augmented levels of TNF-α, IL-1β and nitrogen-derived species in the plasma. With regard to organ injury, absence of IL-10 enhanced the renal, hepatocellular and pancreatic dysfunction caused by zymosan administration. All of these parameters significantly influenced the systemic toxicity and the overall survival at 12 days, which was significantly lower in IL-10 knockout mice. Therefore, this study demonstrates that the absence of endogenous IL-10 enhances the MODS induced by zymosan in mice.

Hind Paw Incision in the Rat Produces Long-Lasting Colon Hypersensitivity

Visceral injury has been shown to alter somatic sensitivity, but little is known about the effect of somatic insult on the viscera. In the present study, we examined (1) the effect of colon inflammation on somatic sensitivity and (2) the affect of hind paw incision on colon sensitivity. After intracolonic administration of trinitrobenzene sulfonic acid (TNBS) or zymosan, visceromotor responses to colorectal distension were increased to post-treatment day 8. Mechanical withdrawal thresholds in the hind paw were decreased in TNBS- and in zymosan-treated rats until post-intracolonic treatment day 2. There was no change in hind paw heat withdrawal latency in either group. Plantar incision of the hind paw resulted in a decrease in both hind paw mechanical withdrawal threshold and heat withdrawal latency and significantly increased the visceromotor response to colorectal distension from postincision days 1 to 8. The colon hypersensitivity was of longer duration than hyperalgesia at the site of hind paw incision. These results support the hypothesis that somatic injury and visceral inflammation can alter central processing of visceral and somatic inputs, respectively. Surgical procedures are common and typically associated with hyperalgesia at and around the site of incision. This report establishes in a model of postsurgical pain and hyperalgesia that a long-lasting visceral hypersensitivity may also accompany postsurgical hyperalgesia.

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.

Gelatinase B/MMP-9 as an inflammatory marker enzyme in mouse zymosan peritonitis: Comparison of phase-specific and cell-specific production by mast cells, macrophages and neutrophils

Neutrophil infiltration during zymosan peritonitis depends on matrix metalloproteinase-9 (MMP-9) activity as it is impaired both in MMP-9 −/− and gelatinase inhibitor-treated animals. The producer cells of MMP-9 and their relative contribution are not known. The aim of this study was to identify and compare the cellular sources, timing and intensity of MMP-9 induction by zymosan in the murine peritoneal cavity. We detected MMP-9 mRNA in unstimulated peritoneal leukocytes and its levels increased after zymosan administration. To detect MMP-9 by flow cytometry, we selected and compared two specific monoclonal antibodies. We show that MMP-9 protein was absent in control peritoneal macrophages, whereas already at 30 min of peritonitis almost all macrophages were producing the enzyme. Conversely, MMP-9 was constitutively present in unstimulated mast cells. Macrophages turned out to be prevalent MMP-9 producers in the early phase of peritonitis. During later stages macrophages kept the high expression of MMP-9 for at least 6 h of inflammation. In contrast, the early phase expression of MMP-9 by neutrophils was limited albeit the highest percentage of MMP-9 + neutrophils was observed at 2 h but absolute numbers of the MMP-9 carrying neutrophils were low at that time. In contrast, during the late phase of peritonitis neutrophils became major producers of MMP-9 as they numerously infiltrated peritoneum. In conclusion, the study reports detection of MMP-9 at the single-cell level during peritonitis, demonstrates unexpectedly fast MMP-9 expression in macrophages and reveals quantitatively phase-specific contribution of mast cells, macrophages and neutrophils.

GLYCOGEN SYNTHASE KINASE 3β INHIBITION REDUCES THE DEVELOPMENT OF NONSEPTIC SHOCK INDUCED BY ZYMOSAN IN MICE

Glycogen synthase kinase 3 has recently been identified as a ubiquitous serine-threonine protein kinase that participates in a multitude of cellular processes and plays an important role in the pathophysiology of a number of diseases. In the present study, we have investigated the effects of 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8), a glycogen synthase kinase 3beta inhibitor, on the development of nonseptic shock caused by zymosan (dose, 500 mg/kg i.p. suspension in saline) in mice. Organ failure and systemic inflammation in mice was assessed 18 h after administration of zymosan and/or TDZD-8; another group of mice was monitored for 12 days (for clinical score and mortality). Treatment of mice with TDZD-8 (dose, 10 mg/kg i.p., 1 and 6 h after zymosan administration) attenuated the peritoneal exudation and the migration of polymorphonuclear cells caused by zymosan. TDZD-8 also attenuated the lung, liver, and pancreatic injury, the renal dysfunction caused by zymosan, and the increase in myeloperoxidase activity caused by zymosan in the lung and in the intestine. Immunohistochemical analysis for inducible nitric oxide synthase, nitrotyrosine, poly(ADP-ribose), CD30, CD30 ligand, and Fas ligand revealed positive staining in lung and intestinal tissues obtained from zymosan-injected mice. The degree of staining for inducible nitric oxide synthase, nitrotyrosine, poly(ADP-ribose), CD30, CD30 ligand, and Fas ligand were markedly reduced in tissue sections obtained from zymosan-injected mice that had received TDZD-8. This study provides the first evidence that TDZD-8 attenuates the degree of zymosan-induced, nonseptic shock in mice.