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 (40 mg/kg) or zymosan supplemented with riboflavin (50 mg/kg). During the first 45 min of inflammation the pain symptoms were scored. At the selected time points (4, 6, 8, 10, 24, and 30 h) 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.     

Characterization of Delta-Sleep-Inducing Peptide-Evoked Release of Met-Enkephalin from Brain Synaptosomes in Rats

Delta-sleep-inducing peptide (DSIP) stimulates the release of Met-enkephalin (Met-ENK) from superfused slices of the rodent lower brainstem in vitro. In our present study, DSIP (10(-10)-10(-9) M) induced a significant release of Met-ENK from medullary synaptosomes of rats. This DSIP-evoked release of Met-ENK was Ca2+ dependent and tetrodotoxin (TTX) insensitive. Furthermore, DSIP (10(-11)-10(-9) M) significantly increased 45Ca2+ uptake in medullary synaptosomes. These results demonstrate that DSIP acts directly on the nerve endings of Met-ENK-containing neurons to release this pentapeptide by generating a Ca2+ influx into these neurons. Effects of DSIP on Met-ENK release in other discrete brain regions were also studied. Significant DSIP-evoked Met-ENK release from synaptosomes was observed in the cortex, hypothalamus, and midbrain (at concentrations of 10(-10) and 10(-9) M) and in the hippocampus and thalamus (only at 10(-9) M), but not in the striatum. In the hypothalamus, the release of Leu-enkephalin from its synaptosomes was slightly, but not significantly, enhanced by DSIP (10(-10)-10(-8) M). Our findings demonstrate that DSIP triggered a Ca2+ influx in nerve endings to induce a subsequent release of Met-ENK from neurons in only certain brain regions.     

Morphine-modulated mast cell migration and proliferation during early stages of zymosan-induced peritonitis in CBA mice

We have previously shown that supplementation of inflammation-inducing zymosan with a high dose ofmorphine inhibits peritoneal influx ofleukocytes in Swiss, C57C3H, Balb/c, and C57BL/6 strains but not in CBA mice. We have also reported that the different pattern of the response to morphine treatment might be, at least partially, due to the inter-strain differences in the peritoneal mast cell (P-MC) number (high in CBA mice versus other strains) and P-MC specific features (high sensitivity to degranulation upon morphine treatment in CBA mice). The aim of the present study was to investigate the mechanism of morphine action on P-MC in CBA mice. In particular, the effects of morphine on the proliferation and migration of P-MC in CBA mice with ongoing zymosan-induced peritonitis modulated by morphine were studied. Morphine alone acted as a strong chemoattractant for P-MC of CBA mice and this effect was opioid receptor-independent. Moreover, flow cytometric analysis showed that i.p. morphine injection induced significant proliferation of P-MC in CBA mice. Therefore, we conclude that the lack of anti-inflammatory effects of morphine during peritonitis in CBA mice might result not only from a unique sensitivity of CBA mast cells to morphine-induced degranulation but also from the fact that mast cell numbers increase at the inflammatory focus. The latter might be due to morphine-induced mast cell proliferation and/or migration.     

Immunologic vasculitis in beige mice with deficiency of leukocytic neutral protease.

Immune complex vasculitis has been induced in normal mice and in mice with features of the Chediak-Higashi syndrome ("beige" mice). The accumulation of neutrophils in peritoneal exudates after the injection of C5a is not quantitatively depressed in beige as compared with normal mice. Immune complex-induced vasculitis in these two strains of mice is not quantitatively different, as assessed by vascular damage (vasopermeability changes and histologic criteria). Measurements of leukocyte enzymes confirm the findings of Vassalli et al. that leukocytes of beige mice lack neutral protease activity. The data suggest that the neutral protease of murine leukocytes does not account for the vascular damage of immune complex vasculitis.     

Role of interleukin-6 in a non-septic shock model induced by zymosan.

In the present study, we used IL-6 knock-out mice (IL-6KO) to evaluate a possible role of IL-6 in the pathogenesis of non-septic shock induced by peritoneal injection of zymosan. A severe inflammatory response characterized by peritoneal exudation, high peritoneal levels of nitrate/nitrite, and leukocyte infiltration into peritoneal exudate was induced by zymosan administration in wild-type control (WT) mice. This inflammatory process coincided with the damage to the lung and small intestine, as assessed by histological examination. Lung, small intestine and liver myeloperoxidase (MPO) activity, indicative of neutrophil infiltration and lipid peroxidation, were significantly increased in zymosan-treated WT mice. Peritoneal administration of zymosan in the WT mice also induced a significant increase in the plasma levels of nitrite/nitrate and in the levels of peroxynitrite, 18 hours after zymosan challenge. Immunohistochemical examination demonstrated a marked increase in the immunoreactivity to nitrotyrosine in the lung of zymosan-treated WT mice. Zymosan-treated IL-6KO showed significantly decreased mortality and inhibition of the development of peritonitis. In addition, IL-6KO mice showed significant protection from the development of organ failure, since tissue injury and MPO was reduced in the lung, small intestine and liver. Furthermore, a significant reduction of suppression of mitochondrial respiration, DNA strand breakage and reduction of cellular levels of NAD+ was observed in ex vivo macrophages harvested from the peritoneal cavity of IL-6KO mice subjected to zymosan-induced non-septic shock. In vivo treatment with anti-IL-6 (5,000 ng/day per mouse, 24 and 1 hour before zymosan administration) significantly reduced the inflammatory process. Taken together, the present study clearly demonstrates that IL-6 exerts a role in zymosan-induced non-septic shock.     

Production of chemokines in vivo in response to microbial stimulation

Members of the chemokine gene superfamily are known to play a central role in leukocyte extravasation; however, their involvement in acute inflammation in response to micro-organisms has not yet been well studied. We have therefore investigated the role of murine macrophage-inflammatory protein (muMIP) 1alpha and muMIP-2 in the inflammatory response mounted against the bacteria Salmonella enteritidis and the Sacchromyces cerevisiae cell wall component, zymosan. Leukocyte extravasation was monitored in murine s.c. air pouches. Both agonists induced accumulation of leukocytes in a dose- and time-dependent manner, with the response peaking after 4 h and declining thereafter. The inflammatory exudate comprised mainly neutrophils; however, an increase in eosinophil accumulation was also observed in response to zymosan. The production of both muMIP-1alpha and muMIP-2 increased with time in response to both the agonists, although production was more sustained in response to the bacteria. Prior treatment of mice with neutralizing Abs against muMIP-1alpha or muMIP-2, either alone or in combination, failed to attenuate the accumulation of leukocytes in response to the agonists. In contrast, the anti-muMIP-2 Abs significantly inhibited leukocyte recruitment in response to S. enteritidis in complement-deficient mice. Taken together, these data show that while muMIP-1alpha and muMIP-2 are produced in response to phagocytosis of micro-organisms in s.c. tissue, under these circumstances components of the complement pathway appear to play a dominant role in the recruitment of neutrophils.     

Acute and long-lasting effects of peripheral injection of caerulein and CCK-8 on the central GABAergic system in mice

Acute and long-lasting effects of peripheral injection of caerulein (CLN) and cholecystokinin octapeptide (CCK-8) on the gamma-aminobutylic acid (GABA) content and the GABA accumulation by aminooxyacetic acid (AOAA) in the discrete brain regions of mice were examined. The content and accumulation of GABA in the striatum, hypothalamus, and frontal cortex was measured with high performance liquid chromatography with electrochemical detection (HPLC-ECD). The GABA content slightly decreased in the striatum 60 min after CLN and CCK-8 were administered, whereas it slightly increased in the hypothalamus and frontal cortex. Moreover, with CLN and CCK-8, the GABA accumulation after AOAA treatment decreased in the striatum and hypothalamus 30 min after injection. Meanwhile, when administering CLN, the GABA content as well as the GABA accumulation after AOAA treatment increased in the striatum and frontal cortex 1 day after injection, and continued to increase the second and third day in the striatum. These results showed that peripheral injection of CLN and CCK-8 had effects on the central GABAergic system with local specific actions, and also the long-lasting and time-dependent biphasic effects of CLN.     

Inhibitory effects of morphine on some inflammation-related parameters in the goldfish Carassius auratus L

Acute peritonitis induced in the goldfish by intraperitoneal injection of a sterile Thioglycollate solution shows a typical pattern with intraperitoneal exudation of serum proteins followed by influx of leucocytes (mainly heterophils/macrophages) correlated with elevated levels of chemotactic factors in peritoneal fluid and blood plasma. Supplementation of Thioglycollate with morphine (20 mg kg(-1) b.w.) does not affect the leakage of serum proteins into peritoneum. In contrast, it reduces the number of exudate peritoneal leucocytes (among them heterophils/macrophages) to the control level and decreases the level of peritoneal fluid/plasma chemoattractants, both effects being reversed by naltrexone pretreatment. Morphine itself acts as a chemokinetic factor for fish leucocytes as it increases their random movements. Therefore inhibitory effects of morphine on accumulation of exudate cells might be explained by inhibition of the production/release of chemotactic factors and/or reduced sensitivity of leucocytes to chemotactic signals. The effects of morphine on the goldfish peritonitis are in concordance with those described recently in Atlantic salmon and CB6 mice.     

Neutrophil elastase (NE)-deficient mice demonstrate a nonredundant role for NE in neutrophil migration, generation of proinflammatory mediators, and phagocytosis in response to zymosan particles in vivo

Neutrophil elastase (NE) remains a controversial player in the process of leukocyte transmigration and much of this controversy stems from conflicting reports on the effects of NE inhibitors. The availability of NE-deficient mice (NE(-/-)) provides a clean and elegant tool for the study of leukocyte migration in vivo. In this study, NE(-/-) mice were used to investigate the role of NE in leukocyte migration through cremasteric venules, as observed by intravital microscopy, induced by locally administered cytokines IL-1beta and TNF-alpha and the particulate stimulus, zymosan. Although no defects in leukocyte responses induced by the cytokines were observed, zymosan-induced leukocyte firm adhesion and transmigration was suppressed in NE(-/-) mice. These responses were also inhibited in wild-type mice when zymosan was coinjected with a specific NE inhibitor. Quantification of inflammatory mediator levels in homogenates of zymosan-stimulated tissues indicated reductions in levels of IL-1beta, KC, and macrophage inflammatory protein-1alpha in NE(-/-) mice. Furthermore, phagocytosis of fluorescent zymosan particles, as observed by intravital microscopy, was diminished in NE-deficient animals. Collectively, the findings of this study indicate a nonredundant role for NE in zymosan-induced leukocyte firm adhesion and transmigration, and that this defect is associated with impaired generation of proinflammatory mediators as well as phagocytosis of zymosan particles in vivo.     

Lipid biosynthesis and metabolism of native and acetylated low density lipoproteins in macrophages stimulated by zymosan in vivo and in vitro]

The effects of zymosan on lipid metabolism in mouse peritoneal macrophages (MPM) in vitro and in vivo were studied with special reference to the following parameters: i) 14C-oleate incorporation into cholesteryl esters (CE), triglycerides (TG), and phospholipids (PL) in MPM incubated with low density lipoproteins (LDL) and acetylated LDL; ii) cholesteryl-14C-oleate-acetyl LDL uptake and 125I-acetyl LDL degradation; iii) oxidative modification of LDL. Zymosan administered to mice caused significant stimulation of 14C-oleate incorporation into CE, TG, and PL with no effect on 3H-cholesterol (Ch) incorporation into CE or 3H-glycerol incorporation into TG and PL in MPM. The 14C-oleate incorporation into cellular lipids was unaffected by 18-hour incubation of MPM with zymosan (100-500 micrograms/ml) but increased after incubation of unstimulated MPM with blood serum and peritoneal fluid harvested harvested from zymosan-treated mice. One possible explanation of this phenomenon is oleyl-CoA formation induction in cytokine-stimulated MPM in vivo. Zymosan decreased the Ch-14C-oleate-acetyl LDL uptake, 125I-acetyl LDL degradation, and Ch esterification in the presence of acetyl LDL in MPM both in vitro and in vivo. An increase in Ch esterification after incubation of MPM with zymosan for 6-18 hours in the presence of LDL was accompanied by an increase in lipid peroxidation of LDL and its electrophoretic mobility. The data obtained suggest that the macrophage acetyl LDL receptor pathway may be inhibited by zymosan and that cytokines released from zymosan-stimulated cells may influence the generation of foam cells.     

Junctional adhesion molecule-C regulates the early influx of leukocytes into tissues during inflammation

Leukocyte recruitment from blood to inflammatory sites occurs in a multistep process that involves discrete molecular interactions between circulating and endothelial cells. Junctional adhesion molecule (JAM)-C is expressed at different levels on endothelial cells of lymphoid organs and peripheral tissues and has been proposed to regulate neutrophil migration by its interaction with the leukocyte integrin Mac-1. In the present study, we show that the accumulation of leukocytes in alveoli during acute pulmonary inflammation in mice is partially blocked using neutralizing Abs against JAM-C. To confirm the function of JAM-C in regulating leukocyte migration in vivo, we then generated a strain of transgenic mice overexpressing JAM-C under the control of the endothelial specific promotor Tie2. The transgenic animals accumulate more leukocytes to inflammatory sites compared with littermate control mice. Intravital microscopy shows that this is the result of increased leukocyte adhesion and transmigration, whereas rolling of leukocytes is not significantly affected in transgenic mice compared with littermates. Thus, JAM-C participates in the later steps of the leukoendothelial adhesion cascade.     

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-alpha, IL-1beta 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.     

Dietary alpha-linked galacto-oligosaccharide suppresses ovalbumin-induced allergic peritonitis in BALB/c mice

To determine whether alpha-linked galacto-oligosaccharide (alpha-GOS) prevents allergic peritonitis, BALB/c mice were fed a synthetic diet with and without alpha-GOS supplementation for 7 d, and were then subcutaneously immunized with ovalbumin on days 0 and 7. The mice were challenged by intraperitoneal injection with ovalbumin on day 14, followed by peritoneal lavage on day 15. The total number of peritoneal exudate cells was significantly lower in the mice fed the alpha-GOS diet than in those fed the control diet. Peritoneal lavage fluid from mice fed the alpha-GOS diet not only had less potency to attract peripheral blood leukocytes and peritoneal exudate cells ex vivo, but also had lower concentrations of monocyte chemoattractant protein-1 (MCP-1) and eotaxin. Preincubation of the cells with alpha-GOS failed to affect the migration to peritoneal lavage fluid. We propose that dietary alpha-GOS reduces cell infiltration in allergic peritonitis by reducing antigen-induced elicitation of MCP-1 and eotaxin in mice.     

Intraperitoneal injection of zymosan in mice induces pain, inflammation and the synthesis of peptidoleukotrienes and prostaglandin E2

Intraperitoneal injection of zymosan in mice induced rapid extravasation and accumulation of plasma protein in the peritoneal cavity. Neutrophils began to appear in the peritoneal cavity after a lag period of approximately 3 hours. The injected mice exhibited a pain response (writhing) during the first 30 minutes after injection, but writhing ceased before protein or cell accumulation had reached maximum levels. The injection of zymosan induced synthesis of PGE2 (measured by RIA) which reached maximum levels at 30 minutes, then declined slowly. Peptido-leukotriene levels (detected by bioassay, RIA and HPLC) increased rapidly after injection, reached a peak within an hour of injection and declined to undetectable levels within 4 hours. The early peptido-LT was predominantly LTC4, while later, LTE4 was the major component. LTD4 levels remained low throughout and no LTB4 was detected at any time. Indomethacin treatment elevated levels of peptido-LTs, reduced PGE2 levels and inhibited writhing. Phenidone reduced peptido-LT levels. In vitro studies demonstrated that zymosan stimulates LTC4 synthesis by peritoneal cells whereas LTE4, LTD4, LTB4 or monoHETES were not detectable (using HPLC methods). The source of enzymes responsible for the in vivo metabolism of LTC4 to LTD4 and LTE4 could not be identified.     

PECAM-1 dampens cytokine levels during LPS-induced endotoxemia by regulating leukocyte trafficking

AimsTo investigate the mechanism by which platelet endothelial cell adhesion molecule 1 (PECAM-1/CD31), an immunoglobulin (Ig)-superfamily cell adhesion and signaling receptor, regulates pro-inflammatory cytokine levels. The purpose of the present investigation was to test the hypothesis that PECAM-1 influences circulating cytokine levels by regulating the trafficking of activated, cytokine-producing leukocytes to sites of inflammation.Main methodsPECAM-1^+/+ and PECAM-1^?/? mice were subjected to lipopolysaccharide (LPS)-induced endotoxemia, and systemic cytokine levels were measured by Bioplex multiplex cytokine assays. Flow cytometry was employed to enumerate leukocytes at inflammatory sites and to measure cytokine synthesis in leukocyte sub-populations. Enzyme-linked immunosorbent assay (ELISA) was used to measure cytokine levels in tissue samples and in supernatants of in vitro-stimulated leukocytes.Key findingsWe confirmed earlier reports that mice deficient in PECAM-1 had greater systemic levels of pro-inflammatory cytokines following intraperitoneal (IP) LPS administration. Interestingly, expression of PECAM-1, in mice, had negligible effects on the level of cytokine synthesis by leukocytes stimulated in vitro with LPS and in peritoneal macrophages isolated from LPS-injected mice. There was, however, excessive accumulation of macrophages and neutrophils in the lungs of PECAM-1-deficient, compared with wild-type, mice — an event that correlated with a prolonged increase in lung pro-inflammatory cytokine levels.SignificanceOur results demonstrate that PECAM-1 normally functions to dampen systemic cytokine levels during LPS-induced endotoxemia by diminishing the accumulation of cytokine-producing leukocytes at sites of inflammation, rather than by modulating cytokine synthesis by leukocytes.     

Regulation of macrophage inflammatory protein-1 alpha expression and function by endogenous interleukin-10 in a model of acute inflammation

In this study we have determined the role of endogenous interleukin (IL)-10 on leucocyte recruitment and production of the CC chemokine macrophage inflammatory protein-1alpha (MIP-1alpha) in a murine model of acute inflammation. Intraperitoneal injection of zymosan produced a dose-dependent cellular infiltration which was concomitant with MIP-1alpha release in the lavage fluids. Release of this chemokine had a functional role since treatment of mice with a specific anti-MIP-1alpha antibody reduced both neutrophil and monocyte accumulation into the peritoneal cavity. An unexpected increase in cell influx and MIP-1alpha production was measured following depletion of resident peritoneal macrophages, as achieved by a 3-day liposome treatment. A similar result was obtained when the zymosan peritonitis response was elicited in IL-10 knock-out mice. In summary we propose a functional cross talk between endogenous IL-10 and this CC chemokine during the host inflammatory response.     

Zymosan-induced luminol-dependent chemiluminescence response of circulating and extravasated leukocytes in experimental sepsis

This study examines a concurrent profiling of circulating and extravasated polymorphonuclear leukocytes (PMNs) in a rat model of experimental sepsis. Fecal peritonitis was induced in Wistar male rats by intraperitoneal instillation of a fecal suspension in saline (1:1 w/v). Blood and peritoneal fluid were collected 8 h following fecal inoculation for the evaluation of inflammatory response of PMNs using zymosan-induced luminol-dependent chemiluminescence. Fifty microliters of pre-diluted blood or peritoneal fluid samples were mixed with 150 microl of reaction mixture (4 x 10(-4) M luminol+50 microg opsonized zymosan+0.1% gelatin in Hank's balanced salt solution) and the chemiluminescence signal was measured in a luminometer at 37 degrees C. Fecal peritonitis caused a significant leukocytopenia (3540+/-297 mm(-3) versus control value of 7525+/-711 mm(-3), p < 0.001) accompanied by massive infiltration of PMNs in the peritoneal cavity (34700+/-4006 versus 7325+/-425 mm(-3), p < 0.001). The phagocytic activity of circulating blood PMNs was down-regulated whereas a significant up-regulation was observed in the activity of PMNs from peritoneal fluid. In conclusion, this study clearly demonstrates sepsis-induced alterations in both blood and peritoneal fluid PMNs and their quantitative assessment may be helpful in disease evaluation and designing effective therapies.     

Effect of Capsular Polysaccharide of Klebsiella pneumoniae on Host Resistance to Bacterial Infections

In normal mice, the total count of peritoneal leukocytes was markedly decreased after intraperitoneal (i.p.) injection of the capsular polysaccharide of Klebsiella pneumoniae (CPS-K) depending on the dosage injected. This decrease was mainly due to the depletion of macrophages, and a decrease in the number of lymphocytes occurred to a lesser extent. CPS-K in relatively smaller doses mobilized polymorphonuclear neutrophilic leukocytes (PMN) into the peritoneal fluid but it decreased them transiently in larger doses. In mice infected i.p. with a virulent strain of Salmonella enteritidis, there was an abundant emigration of PMN into the peritoneal fluid. When 200 μg of CPS-K was injected i.p. immediately before bacterial challenge, emigration of PMN was markedly delayed for 48 hr after infection. Associated with this suppressed emigration of PMN, the numbers of macrophages and lymphocytes in the peritoneal fluid were significantly less in mice treated with CPS-K than those in untreated control mice for 48 hr after infection. The numbers of both cell-associated and extracellular bacteria in the peritoneal fluid were markedly greater in mice treated with CPS-K than those in untreated control mice. In both in vivo and in vitro experiments, ingestion of bacteria by macrophages and PMN was not blocked by CPS-K or neutral CPS-K, the active substance responsible for the infection-promoting effect of CPS-K. It appeared that CPS-K somehow impaired the intraphagocytic bactericidal activity.     

Protein A induced protection against experimental Candidiasis in mice

Staphylococcus aureus protein-A (SpA), an important multipotent immunostimulator, increased the resistance to infection with Candida albicans in Swiss albino mice. The mice treated with repeated immunologically active doses (1 μg/mouse) of SpA, pre- and post-infection, showed one hundred percent protection against experimental candidiasis, and constituted the first such report. Protection could be demonstrated on the basis of leukocyte counts, colony forming unit (CPU) kinetics in liver, spleen, kidney and peritoneal cavity, and phagocytosis by monocyte-derived macrophages. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effect of halothane anesthesia on extravascular mobilization of neutrophils

The ability of neutrophil leukocytes to extravasate into the peritoneal cavity in response to an intraperitoneal injection of bacterial endotoxin was studied in mice. The normal response of a marked accumulation of intraperitoneal neutrophils was completely abolished by halothane anesthesia. It was further shown that such abolition depended upon the presence of halothane duringthe time the extravasation would normally be occurring. The evidence points toward an effect on either the leukocyte or the vessel rather than a non-specific “stress” effect. It is suggested that the effect is on the neutrophil, rendering it less deformable and, hence, less able to undergo trans-vascular diapedesis.