Peritoneal Leukocytes Research Articles

CD156 Transgenic Mice

CD156 (ADAM8) is part of the ADAM family of proteins with the catalytic site consensus sequence of metalloprotease and disintegrins. To examine the role of CD156 in vivo, we generated mutant CD156 (eCD156) transgenic mice expressing the ectodomain of CD156 under the control of the α1-antitrypsin (AT) promoter. One of the transgenic mice designated ATMS2-TG18 expressed a 1.84 kb mRNA which was predicted to be a truncated CD156. The expression of the transgenic CD156 mRNA in ATMS2-TG18 mice was abundant in the liver and slight in kidney. Turpentine oil (TO) and lipopolysaccharide (LPS) markedly upregulated the expression. Soluble CD156 (sCD156) was produced constitutively, and increased after the treatment with TO. Casein-induced peritoneal leukocyte infiltration was significantly less extensive in ATMS2-TG18 than non-transgenic mice. The expression of L-selectin in neutrophils (PMN) from peripheral blood leukocytes (PBL) was more strongly downregulated in ATMS2-TG18 than non-transgenic mice, suggesting that L-selectin in PMN from ATMS2-TG18 mice was shed by sCD156. In contrast, oxazolone (Ox)-induced contact hypersensitivity reactions (CHR) were more marked in ATMS2-TG18 than non-transgenic mice. The expression of E-selectin mRNA was detected in inflammatory skin sites from ATMS2-TG18, but not non-transgenic mice, suggesting that sCD156 may activate the endothelial cells and lead to the upregulation of E-selectin. These results suggest that CD156 regulates leukocyte infiltration directly or indirectly.

Serum concentrations of growth factors in women with and without endometriosis: the action of anti-endometriosis medicines

Endometriosis is a common gynecologic syndrome of unknown etiology and pathogenesis. Growth factors and inflammatory mediators produced by peritoneal leukocytes have recently been postulated to participate in the pathogenesis of endometriosis. Angiogenic factors released from peritoneal macrophages may also play a role in the development of this disease. In the present study, we investigate the soluble levels of vascular endothelial growth factor (VEGF), epidermal growth factor-receptor (EGF-R), granulocyte/macrophage-colony stimulating factor (GM-CSF), Insulin-like growth factor-1 (IGF-1) and interferon-gamma (IFN-γ) in the serum of 28 women with and 20 without endometriosis. We also compared these levels before, during and after treatment with danazol and leuprorelin acetate depot, the two therapeutic regiments of choice concerning this disease. We found that only sVEGF levels were higher in women with endometriosis in comparison to controls ( P<0.001) while sEGF-R is not present. GM-CSF, IGF-1 and IFN-γ soluble levels are not affected in either healthy or endometriotic subjects. The 6-month treatment with danazol decreased sVEGF levels ( P<0.02) and increased sEGF-R levels ( P<0.001). These observations support the view that VEGF may be associated with the disease process and that danazol may bring sVEGF levels to a normal threshold. However, future studies will be focused on the anti-angiogenic control of the action of VEGF in patients with endometriosis.

Biodefense function of omental milky spots through cell adhesion molecules and leukocyte proliferation.

To evaluate the immunological functions of the greater omentum in the peritoneal cavity, the localization of cell adhesion molecules (CAMs) on mesothelial cells and leukocytes in the omental milky spots were studied in normal and lipopolysaccharide (LPS)-stimulated mice by means of immunoelectron microscopy. The milky spots featured numerous leukocytes among the dome-shaped mesothelial cells, even in the normal stable state. Leukocyte integrins LFA-1, Mac-1, and VLA-4 were preferentially localized to microvilli and ruffles of macrophages and lymphocytes. The mesothelial cells of the milky spots showed higher ICAM-1 levels than did those of other omental regions, and fibronectin was detected in the stomata. The number of leukocytes markedly increased following an increase in proliferating cell nuclear antigen (PCNA)-positive cells in the milky spots after LPS stimulation. The mesothelial cells contained VCAM-1 newly restricted to the microvilli and increasing amounts of ICAM-1. These results show that the omental milky spots are active sites for leukocyte migration and peritoneal leukocyte supply because of the presence of adhesion molecules and active cell proliferation. Proliferative active leukocytes and those that have migrated from vessels pass through the stomata via an interaction of VLA-4 and fibronectin, adhere to the microvilli of the activated mesothelial cell surface as the result of an interaction between ICAM-1/VCAM-1 and integrins, and exude into the peritoneal cavity. Much of the exudation and adhesion of leukocytes seen in the milky spots of LPS-stimulated mice may be attributable to an increase in cell proliferation and in the amounts of ICAM-1 and VCAM-1.

Chemical sympathectomy increases numbers of inflammatory cells in the peritoneum early in murine listeriosis

Here, we investigated the effects of sympathectomy on systemic bacterial loads following infection with Listeria monocytogenes, and on innate and specific immune responses in the peritoneum. Sympathectomy decreased systemic bacterial loads, and increased the number of peritoneal leukocytes and the percentage of peritoneal macrophages three days postinfection. This suggests that sympathectomy-induced decreases systemic bacterial loads are associated with increased recruitment of inflammatory cells into tissues during the innate immune response.

In vitro anti-inflammatory and anti-proliferative activity of sulfolipids from the red alga Porphyridium cruentum.

A sulfoglycolipidic fraction (SF) isolated from the red microalga Porphyridium cruentum was analyzed for fatty acid composition and assayed for ability to inhibit, in vitro, the generation of superoxide anion in primed leucocytes and the proliferation of a panel of human cancer cell-lines. Results demonstrated that SF contained large amounts of palmitic acid (26.1%), arachidonic acid (C20: 4 omega-6, 36.8%), and eicopentaenoic (C20:5 omega-3, 16.6%) acids, and noticeable amounts of 16:1n-9 fatty acid (10.5%). It strongly inhibited both the production of superoxide anion generated by peritoneal leukocytes primed with phorbol myristate acetate (IC(50): 29.5 microg/mL), and the growth of human colon adenocarcinoma DLD-1 and to a lesser extent of human breast adenocarcinoma MCF-7, human prostate adenocarcinoma PC-3, and human malignant melanoma M4 Beu cell-lines, and therefore might have a chemopreventive or chemotherapeutic potential, or both. It was found markedly more cytotoxic than sulfoquinovosyldiacylglycerols from plant used as a standard (STD), due to a stronger ability to inhibit DNA alpha-polymerase (IC(50): 378 microg/mL, vs 1784 microg/mL for STD). After a 48-h continuous treatment, IC(50) values for growth inhibition were in the range of 20-46 microg/mL instead of 94 to >250 microg/mL for STD, and those for inhibition of metabolic activity were in the range of 34-87 microg/mL instead of >250 microg/mL for STD. The higher anti-proliferative effect was observed on colon adenocarcinoma DLD-1 cells, and the weaker effect was observed on breast adenocarcinoma MCF-7.

Thiazolidinediones, Agonisten des PPAR-γ-Rezeptors (peroxisomaler proliferatoraktivierter Rezeptor) reduzieren die peritoneale Makrophagenanzahl - Neue medikamentöse Therapieoptionen für die Inflammation und Infertilität bei Endometriose? -

Die Migration von Makrophagen in die Peritonealhöhle ist ein wesentlicher pathophysiologischer Faktor der Endometriose. Frühere Daten aus unserem Labor deuteten darauf hin, dass RANTES (Regulated on Activation, Normal T cell Expressed and Secreted) ein mögliches Ziel für Therapieformen ist, die die Infertilität und Schmerzen behandeln wollen. Wir charakterisieren die inflammatorische Antwort in einem In-vivo-Mausmodell der Peritonitis und beschreiben den anti-inflammatorischen Effekt von Ciglitazone, einem Thiazolidinedion (TZD) und PPAR-γ-Aktivator (peroxisomaler, proliferatoraktivierter Rezeptor γ).

The professional phagocytes of sea bass (Dicentrarchus labrax L.): cytochemical characterisation of neutrophils and macrophages in the normal and inflamed peritoneal cavity

In order to identify the phagocytic cells of sea bass, the peritoneal leucocyte population of fish injected intraperitoneally with Photobacterium damselae subspecies piscicida was studied by light microscopy using cytocentrifuge preparations stained by the Antonow technique for peroxidase detection. Among the leucocytes present in the peritoneal exudate of the infected fish (macrophages, neutrophils, eosinophilic granular cells, lymphocytes and thrombocytes), macrophages and neutrophils were the only phagocytic cells. Neutrophils were easily distinguished from macrophages in Antonow stained preparations by the pattern of peroxidase positivity. Using ultrastructural cytochemistry, neutrophils were found to have abundant cytoplasmic granules positive for peroxidase and arylsulphatase and were negative for alpha-naphthyl butyrate (ANB) esterase. In contrast, ANB esterase activity was detected in macrophages. These leucocytes were typically negative for peroxidase, but ocasionally, some macrophages with peroxidase or arylsulphatase-positive vacuoles were observed. Both phagocytes had cytoplasmic granules positive for acid phosphatase. Glycogen particles were found in the cytoplasm of the two phagocytic cells, but they were much more abundant in neutrophils. Macrophages were much more abundant than neutrophils in the peritoneal cavity of non-injected sea bass but early after the intraperitoneal injection of bacteria, the number of neutrophils increased quickly and extensively. Higher numbers of intraperitoneally injected bacteria were found inside macrophages as compared to neutrophils because macrophages strongly predominated in the peritoneal population at the time of injection. However, when the bacteria were injected into peritoneal cavities with high numbers of neutrophils (attracted by a previous injection of 12% casein), the percentage of neutrophils with phagocytosed bacteria increased, approaching that of infected macrophages. Taken together, these results show that in sea bass, as in many other organisms, in addition to macrophages, neutrophils are important phagocytic cells, the relative participation of each of the two phagocytes in defense mechanisms against infection depending on the opportunity to encounter the invading infectious agents.

The role of forced swim test on neutrophil leukocytosis observed during inflammation induced by LPS in rodents

Adult male rats were administered intrapleural (ipl) or intraperitoneal (ip) injection of lipopolysaccharide (LPS), 24 h after being submitted to forced swim test (FST). Four hours after LPS challenge, an increase in pleural and peritoneal leukocyte and neutrophil counts in animals not exposed to FST was noted. FST induced a marked increase in pleural, but not in peritoneal, neutrophil leukocytosis. The results suggest that lowered mood may increase inflammatory response to LPS.

Utility of a peritoneal dialysis leukocyte test strip in the diagnosis of peritonitis.

Expeditious diagnosis of peritonitis remains a significant goal in the management of patients maintained on peritoneal dialysis. Several attempts to use leukocyte esterase reagent strips to diagnose peritonitis have been described. In this study we examined the usefulness of a new reagent strip, the PeriScreen Test Strip, in the diagnosis of peritonitis. A series of 72 peritoneal effluent samples obtained from 22 maintenance peritoneal dialysis patients is reported. In this study, the test strips had a sensitivity of 100% and a specificity of 98.3% as compared to an abnormal leukocyte count. Thus, in the diagnosis of peritonitis we believe that the PeriScreen Test Strip can be used as a simple bedside screening test to exclude peritonitis in peritoneal dialysis patients.

L-2-Oxothiazolidine-4-Carboxylate: An Agent that Modulates Lipopolysaccharide-Induced Peritonitis in Rats

L-2-Oxothiazolidine-4-carboxylate (OTZ), a cysteine precursor, is a substrate for intracellular glutathione synthesis. As shown previously, OTZ prevents free-radical induced cellular damage during in vitro simulation of peritoneal dialysis. In the present study, we examined the effect of adding OTZ to peritoneal dialysis solution on peritoneal function and structure during lipopolysaccharide (LPS)-induced peritonitis in rats. In addition, we studied the effects of pretreatment with OTZ (given orally) on the effects of LPS-induced peritonitis in rats. Peritonitis was induced in rats by adding LPS (5 microg/mL) to the dialysis fluid. For acute experiments, rats were exposed to a single infusion of dialysis solution containing LPS or to LPS plus 5 mmol/L OTZ; peritoneal cell counts and permeability were determined after 4 hours. Alternatively, rats were pretreated with OTZ added to the drinking water (0.1%) for 10 days prior to infusion of LPS. For chronic experiments, peritoneal dialysis was performed over a 3-week period in rats with implanted peritoneal catheters. On days 8, 9, and 10 of the experiment, the rats were infused intraperitoneally with solution containing LPS (5 micro/mL), or LPS plus 5 mmol/L OTZ, to induce acute peritonitis. At the end of dialysis (10 days after the episodes of peritonitis), peritoneal function was assessed using a peritoneal equilibration test (PET), and peritoneal biopsies were taken to assess effects on peritoneal morphology. In the acute experiments, exposure to LPS led to increased peritoneal cell counts (+61% vs control, p < 0.05) and enhanced permeability of the peritoneum, leading to a loss in ultrafiltration (-63%, p < 0.0005). The glutathione concentration in peritoneal leukocytes also decreased during acute peritonitis (-31%, p < 0.05). During LPS-induced peritonitis, OTZ prevented the increase in dialysate cell count and the decrease in cellular glutathione content. Simultaneous administration of OTZ did not prevent the increased peritoneal permeability induced by LPS. However, in rats pretreated with OTZ, LPS-induced permeability to protein was significantly lower than in the nontreated animals (0.049 +/- 0.011 vs 0.087 +/- 0.034, p < 0.05). In the chronic experiments, LPS-induced peritonitis did not lead to any functional differences in peritoneal transport at the end of 3 weeks of dialysis. However, LPS-induced peritonitis led to increased thickness of the peritoneum and neovascularization within peritoneal interstitium compared to peritonitis-free animals. In contrast to the LPS-treated animals, the peritoneum of the rats exposed to LPS in the presence of OTZ was of a thickness similar to that in the control rats. Supplementation of dialysis fluid with OTZ prevented changes in cellular glutathione levels and dialysate cell counts during acute peritonitis in rats. During chronic dialysis in rats exposed to intermittent peritonitis episodes, OTZ prevented increased thickening and neovascularization of the peritoneum. Our results suggest this may help to protect the peritoneal membrane during episodes of peritonitis.

Characterisation of gilthead seabream acidophilic granulocytes by a monoclonal antibody unequivocally points to their involvement in fish phagocytic response.

The various cell types involved in fish phagocytic defence have not been properly established because of the morphological heterogeneity of leucocytes and the lack of appropriate cell-surface markers. In this study, we report the production and characterisation of a monoclonal antibody, G7, which specifically recognises gilthead seabream acidophilic granulocytes, as assayed by immunofluorescence and immunoelectron microscopy. The antibody reacted with 40%-50% of head-kidney and peritoneal exudate leucocytes and 10%-20% of spleen and peripheral blood leucocytes. More importantly, G7(+) acidophils constituted 85% of the head-kidney leucocytes showing phagocytic activity towards the fish pathogenic bacterium Vibrio anguillarum. The results are discussed in relation to the role played by this cell type in fish immune responses.

Immunostimulation in the rainbow trout ( Oncorhynchus mykiss) following intraperitoneal administration of Ergosan

The present work provides information concerning the immunostimulatory activity of Ergosan, an algal based product, injected intraperitoneally in the rainbow trout ( Oncorhynchus mykiss). Ergosan is composed of 0.002% unspecified plant extract, 1% alginic acid from Laminaria digitata, and 98.998% algal based carrier. Migration of leucocytes into the peritoneal cavity was stimulated at doses ≥1 mg ml −1. A single dose of 1 mg significantly augmented the proportion of neutrophils, degree of phagocytosis, respiratory burst activity and expression of interleukin-1β (IL-1β), interleukin-8 (IL-8) and one of the two known isoforms of trout tumour necrosis factor-α (TNF2) in peritoneal leucocytes at 1 day post-injection. Humoral immune parameters were less responsive to intraperitoneal Ergosan administration, with complement stimulation only evident in the 1 mg treated group at 2 days post-injection. Antiprotease and lysozyme activity were unaffected by Ergosan over a 7-day time period at the doses examined.

Changes in the antioxidant content of mononuclear leukocytes from mice with endotoxin-induced oxidative stress.

Oxidative stress, associated with a high production of reactive oxygen species (ROS) by immune cells, is involved in the endotoxic shock caused by endotoxin. This oxidative stress is linked to the inability of the immune cells to maintain adequate levels of antioxidants with free radical-scavenging action. Glutathione (GSH) and ascorbic acid (AA) are intracellular and extracellular antioxidants (ROS scavengers) that improve the leukocyte functions. Therefore, in the present work we have determined the reduced GSH and AA content in axillary nodes, spleen, thymus and peritoneal mononuclear leukocytes from BALB/c mice subjected to lethal endotoxic shock produced by intraperitoneal injection of E. coli lipopolysaccharide (LPS, 100 mg/kg), at several times (0, 2, 4, 12 and 24 h) after LPS injection. Endotoxic shock decreased the levels of AA in the leukocytes from the three organs as well as the levels of GSH in axillary nodes and spleen cells while it increased the GSH levels in thymus and peritoneum. These results are in agreement with the oxidative stress and the altered function previously observed in those leukocytes, and they suggest that antioxidant administration may be useful for the treatment of endotoxic shock and other oxidative stress situations with altered immunological responses.

Leukocyte function and life span in a murine model of premature immunosenescence

Aging associates with a decline of physiological functions, including the function of the nervous and the immune system. These aged-related changes occur in various degrees in different members of a mouse outbred population. Accordingly, we have proposed a model of premature immunosenescence in mice, based on the demonstration of premature decline in the behavioral response in a simple T-maze and in several immune functions in Swis outbred mice. Those mice with a worst (slow) performance in this test (linked to a higher emotional response to stress) show a shorter life span and a decreased immune function when compared to fast mice. In order to provide biomarkers of ‘biological aging’ related to health and survival, the present longitudinal study includes the analysis of several immunological parameters such as, proliferative response to mitogen Con A, NK activity and cytokine (TNFα, IL-1β and IL-2) release by peritoneal leukocytes from female Swiss mice. Slow mice showed a lower proliferative response to Con A, IL-2 and IL-1β release, an impaired NK activity and an increased TNFα production as compared to fast mice. Moreover, the age-associated decline of these functions is more strikingly slow than in fast mice. In summary, we propose the above immunological parameters, that change with aging at a different rate in members of a same population, as useful biomarkers to asses the rate of biological aging in mice.

Protection against translocating Salmonella typhimurium infection in mice by feeding the immuno-enhancing probiotic Lactobacillus rhamnosus strain HN001.

The probiotic lactic acid bacterium Lactobacillus rhamnosus (strain HN001) is known to stimulate enhanced innate and acquired immune responses in mice. following oral delivery. Here, the ability of HN001 to confer immune enhancement and protection against an oral challenge of Salmonella tYphimurium was investigated. HN001-fed and non-probiotic-fed control BALB/c mice were challenged with either a single dose of S. typhimurium (ATCC strain 1772), or with five repeated daily doses of the pathogen; post-challenge clinical, behavioural, bacteriological and immunological parameters were assessed. Mice began to show ostensible signs of infection 3-4 days following the initiation of Salmonella challenge, and the first mortalities were observed after 6 days. Following single-dose Salmonella challenge, HN001-fed mice maintained a higher mean pre-mortality general health score than control mice; retained significantly greater food and water intake and weight gain, produced higher titres of serum and intestinal tract anti-Salmonella antibodies, and showed greater overall survival of infection (27/30 mice surviving at 21 days post-challenge, compared to 2/29 in the control group). Following repeated-dose Salmonella challenge, HN001-fed mice had significantly lower mean pathogen burdens in visceral organs (spleen, liver) compared to controls, and additionally, blood and peritoneal leucocytes obtained from HN001-fed mice exhibited significantly higher ex vivo phagocytic capacity compared to control-mice. This study affirms that Lb. rhamnosus strain HN001 displays immuno-enhancing properties in S. typhimurium-infected mice, and demonstrates that oral delivery of this probiotic can promote increased protection against a highly virulent enteric bacterial pathogen.

Expression of Defensin Antimicrobial Peptides in the Peritoneal Cavity of Patients on Peritoneal Dialysis

To investigate the expression and regulation of defensins in the peritoneal cavity of peritoneal dialysis (PD) patients. The presence of defensins in the peritoneal cavity was assessed using reverse transcription polymerase chain reaction (RT-PCR). In vivo defensin expression was analyzed in human peritoneal membrane biopsies and in peritoneal cavity leukocytes isolated from spent dialysate. Defensin expression in vitro was assessed in cultured human peritoneal mesothelial cells (HPMC) and confirmed with PCR Southern blot and DNA sequencing. The effect of tumor necrosis factor alpha (TNFalpha) and epidermal growth factor (EGF) on beta2 defensin expression in HPMC was analyzed by Northern blot analysis and RT-PCR respectively. Both alpha and beta classes of defensins are expressed in the peritoneal cavity of PD patients. Messenger RNA for the alpha-defensin human neutrophil peptide 3 and for beta-defensin-1 (hbetaD-1) were found in preparations containing predominantly peritoneal leukocytes, whereas beta-defensin-2 (hbetaD-2) is expressed by HPMC. HPMC isolated from different individuals displayed variability in both basal hbetaD-2 expression and in response to stimulation by TNFalpha. Conversely, EGF consistently downregulated the level of hbetaD-2 message in HPMC. Alpha- and beta-defensins are expressed in the peritoneal cavity, and hbetaD-2 is the main defensin present in the peritoneal membrane. Variable levels of expression of hbetaD-2 by mesothelial cells were seen, with evidence of regulation by cytokines and growth factors. This provides evidence for a previously unknown mechanism of innate immunity at that site.

Oleanonic acid, a 3-oxotriterpene from Pistacia, inhibits leukotriene synthesis and has anti-inflammatory activity

One of the best known bioactive triterpenoids is oleanolic acid, a widespread 3-hydroxy-17-carboxy oleanane-type compound. In order to determine whether further oxidation of carbon 3 affects anti-inflammatory activity in mice, different tests were carried out on oleanolic acid and its 3-oxo-analogue oleanonic acid, which was obtained from Pistacia terebinthus galls. The last one showed activity on the ear oedema induced by 12-deoxyphorbol-13-phenylacetate (DPP), the dermatitis induced by multiple applications of 12- O-tetradecanoyl-13-acetate (TPA) and the paw oedemas induced by bradykinin and phospholipase A 2. The production of leukotriene B 4 from rat peritoneal leukocytes was reduced by oleanonic acid with an IC 50 of 17 μM. Negligible differences were observed in the response of both triterpenes to DPP, bradykinin, and phospholipase A 2, while oleanonic acid was more active on the dermatitis by TPA and on the in vitro leukotriene formation. In conclusion, the presence of a ketone at C-3 implies an increase in the inhibitory effects on models related to 5-lipoxygenase activity and on associated in vivo inflammatory processes.

Ectopic endometrial cells express high concentrations of interleukin (IL)-8 in vivo regardless of the menstrual cycle phase and respond to oestradiol by up-regulating IL-1-induced IL-8 expression in vitro.

Endometriosis, an oestrogen-dependent disorder affecting women of reproductive age, is associated with active angiogenesis and an increased recruitment of leukocyte into the peritoneal cavity where the implants often develop. The role of oestrogens in the development of endometriosis has been clearly established, but the biochemical mechanisms of their action are still not clearly elucidated. The present study shows that interleukin-1 (IL-1) induces interleukin-8 (IL-8) secretion by endometriotic cells and that oestradiol enhances endometriotic cell responsiveness to IL-1. In contrast, no significant cell responsiveness to progesterone either alone in the culture medium or in combination with oestradiol was noted. Positive immunostaining for IL-8 was observed throughout endometriotic tissue, and no perceptible difference in the intensity of staining regarding the menstrual cycle phase was observed. Together with the in-vitro data, this suggests that IL-8 expression in endometriotic tissue is not subject to cyclic variation. Furthermore, this study provides evidence that oestradiol indirectly up-regulates the expression by ectopic endometrial cells of IL-8, a cytokine endowed with neutrophil chemotactic and angiogenic properties. This may contribute to peritoneal leukocyte recruitment and to the growth of endometriotic implants, and may be a new mechanism for oestradiol action in endometriosis.

Regulation of leukocyte adhesion to heart by the tripeptides feG and feG(NH2)

The role of the D-isomeric form of the salivary gland tripeptide FEG (feG) and its carboxyl-amidated derivative, feG(NH2), in regulating leukocyte adherence to nonfixed atrial slices from Sprague-Dawley rats was examined under static conditions. Optimal binding of the leukocytes was seen if the leukocytes were treated with platelet activating factor (PAF; 10(-9)M). The increased adherence of PAF-treated peripheral blood leukocytes was totally inhibited by both feG and feG(NH2) (10-9M), as well as by antibodies against CD18 and CD49d. In contrast, the binding of peritoneal leukocytes was blocked only by CD49d antibody. Circulating leukocytes obtained from lipopolysaccharide (LPS) treated (2 mg/kg ip) rats did not bind to atrial slices obtained from normal hearts, but readily bound to atrial slices obtained from LPS-treated rats. This leukocyte binding was inhibited by in vivo feG treatment (100 microg/kg ip, 24 h before harvest) or by treating the isolated cells with feG (10(-9)M). The amidated peptide feG(NH2) reduced neutrophil accumulation in the atrium elicited by ip injection of LPS, whereas feG was ineffective. The reduction in neutrophil infiltration into the myocardium by feG(NH2) and the prevention of leukocyte interaction with myocytes seen with both feG and feG(NH2) probably results in hindered leukocyte migration in the inflamed heart, resulting in less tissue damage. The inhibition by these tripeptides on neutrophil adhesion to myocytes suggests that salivary glands hormones regulate the severity of cardiac inflammation.

Bothrops asper and Bothrops jararaca snake venoms trigger microbicidal functions of peritoneal leukocytes in vivo

Venoms from snakes of the genus Bothrops cause pronounced local effects in the victims. These alterations result not only from the direct toxic action of venom components, but also from the prominent inflammatory reaction associated with these envenomations. In this study we investigated the ability of Bothrops asper (BaV) and Bothrops jararaca (BjV) venoms to induce cellular influx and microbicidal functions in leukocytes. BaV and BjV (5 μg/animal) caused a long lasting infiltration of leukocytes (3–48 h) when injected into mouse peritoneal cavity. Both venoms increased phagocytosis and production of hydrogen peroxide (H 2O 2) by polymorphonuclear (PMN) and mononuclear (MN) peritoneal leukocytes. In addition, nitric oxide (NO) production by macrophages was also enhanced after the venom injections. This effect was inhibited by treating animals with L-NAME and aminoguanidine, thus suggesting the induction of iNOS synthesis by the venoms. Western blot analysis confirmed the expression of iNOS in macrophages. BaV and BjV injection led to increased levels of IFN-γ at the site of inflammation. Since IFN-γ is an effective inducer of iNOS expression, an indirect action of the venoms on iNOS expression can be proposed. A marked formation of nitrotyrosine-containing proteins was also observed in macrophage homogenates. Based on these results, we suggest that reactive oxygen and nitrogen-derived species are involved in the pathogenesis of the local tissue damage characteristic of Bothrops sp envenomations.