O papel da flagelina e do sistema de secreção de Escherichia coli enteroinvasora na resposta imune inata dos macrófagos / The role of flagellin and secretion system of enteroinvasive Escherichia coli in the immune response innate macrophages

Escherichia coli enteroinvasora (EIEC) é um dos agentes etiológicos da disenteria bacilar. Seu processo fisiopatológico é desencadeado pela expressão de fatores de virulência, que proporcionam sua invasão e sobrevivência nas células do hospedeiro, ativando o sistema imune inato e adaptativo da mucosa intestinal. Trabalhos recentes têm salientado a importância do sistema de secreção e da flagelina bacteriana como agonista de receptores da imuninade inata dos macrófagos, em especial alguns dos receptores do tipo NLR. Uma vez que esta espécie de E. coli também é capaz de expressar flagelina e fazer a montagem completa do flagelo e do sistema de secreção do tipo III, a nossa proposta foi avaliar o papel da flagelina e do sistema de secreção de EIEC na resposta imune dos macrófagos murinos. Para isso, utilizamos três cepas de EIEC: a cepa selvagem; a cepa mutante no gene responsável pela síntese da flagelina; e a cepa sem o plasmídio de virulência plnv, deficiente no sistema de secreção, para a infecção de macrófagos peritoniais de camundongos C57BI/6, caspase-1-/-, IPAF-/- e ASC-/-. Neste estudo foi possível observar que o escape bacteriano e a morte dos macrófagos infectados por EIEC, assim como a ativação da caspase-1 e posterior secreção de IL-1ß é independente da flagelina bacteriana, mas dependente do sistema de secreção, além disso, a ativação da caspase-1 de macrófagos infectados por EIEC é dependente do receptor IPAF e parcialmente da proteína adaptadora ASC. Assim, no nosso modelo, a ativação da caspase-1 dos macrófagos infectados por EIEC parece estar envolvida com o processamento e secreção de IL-1ß e, possivelmente na secreção de IL-18, mas não na morte celular. No modelo de infecção in vivo, o sistema de secreção bacteriano foi importante para a sobrevivência bacteriana no hospedeiro, assim como para a indução de uma resposta inflamatória no local da infecção. Ainda, a caspase-1 parece ter um papel importante para o controle da infecção in vivo por EIEC, podendo assim contribuir para uma resposta imune protetora do hospedeiro

Enteroinvasive Escherichia coli (EIEC) is one of the etiologic agents responsible for bacillary dysentery. The pathophysiological process induced by this bacteria is triggered by the expression of virulence factors that provide the invasion and survival in host cells, resulting in activation of innate and adaptive immune system present on intestinal mucosa. Recent studies have emphasized the importance of the secretion system and bacterial flagellin as agonist of innate immune receptors present in macrophage, especially NLR (Nod like receptors). Then, our proposal was evaluate the role of flagellin (f1iC) and secretion system of EIEC in the induction of immune response of murine macrophages using the EIEC strains wild type (WT), mutant flagellin gene (f1iC), and a strain deficient in secretion system (DSS) for infection of peritoneal macrophages of C57Bl/6, caspase-1-/-, IPAF-/- and ASC-/-- mice. In this study we observed that the bacterial escape and death of infected macrophages with EIEC, the caspase-1 activation and subsequent IL-1ß secretion is independent of bacterial flagellin, but dependent of secretion system, moreover, the caspase-1 activation in infected macrophages is IPAF-dependent and partially dependent of the adapter protein ASC. Thus, in our model, the caspase-1 activation in EIEC infected macrophages seems to be involved with the processing and secretion of IL-1ß and possibly with the secretion of IL-18, but not involved with cell death. In the infection model in vivo, bacterial secretion system was important for bacterial survival in the host, as well as for the inflammatory response induction at the infection site. In addition, caspase-1 seems to have an important role to the control of in vivo infection by EIEC and can contribute to a protective immune response of the host

In vitro study of the effect of a probiotic bacterium Lactobacillus rhamnosus against herpes simplex virus type 1

BACKGROUND: Due to the emergence of drug resistance in herpes simplex virus type 1 (HSV-1), researchers are trying to find other methods for treating herpes simplex virus type 1 infections. Probiotic bacteria are effective in macrophage activation and may have antiviral activities. OBJECTIVE: This study aimed at verifying the direct effect of Lactobacillus rhamnosus, a probiotic bacterium, in comparison with Escherichia coli, a non-probiotic one, on HSV-1 infection, and determining its effect on macrophage activation for in vitro elimination of HSV-1 infection. METHODS: The above bacteria were introduced into HSV-1 infected Vero cells, and their effects were examined using both MTT and plaque assay. To determine macrophage activation against in vitro HSV-1 infection, J774 cells were exposed to these bacteria; then, macrophage viability was examined with the MTT method, and tumor necrosis factor alpha (TNF-α), interferon-gamma (IFN-γ), and nitric oxide (NO) assessments were performed using the ELISA method. RESULTS: A significant increased viability of macrophages was observed (p < 0.05) in the presence of Lactobacillus rhamnosus before and after HSV-1 infection when compared with Escherichia coli as a non-probiotic bacterium. However, tumor necrosis factor α concentration produced by Escherichia coli-treated J774 cells was significantly higher than Lactobacillus rhamnosus-treated J774 cells (p < 0.05). interferon-gamma and NO production were not different in the groups treated with Escherichia coli or with Lactobacillus rhamnosus. CONCLUSION: The results of this study indicate that Lactobacillus rhamnosus enhances macrophage viability for HSV-1 elimination and activation against HSV-1 more effectively, when compared with non-probiotic Escherichia coli. it also seems that receptor occupation of macrophage sites decreases HSV-1 infectivity by both of the studied bacteria.

Legionella lipoprotein activates toll-like receptor 2 and induces cytokine production and expression of costimulatory molecules in peritoneal macrophages

Legionella bacterium, an intracellular pathogen of mononuclear phagocytes, causes acute fatal pneumonia, especially in patients with impaired cellular immune responses. Until recently, however, the toll-like receptor (TLR) engagement of bacterial proteins derived from Legionella is uncertain. We previously showed that a 19-kDa highly conserved peptidoglycan-associated lipoprotein (PAL) of Legionella pneumophila induced the PAL-specific B cell and T cell responses in mice. In this study, we observed that the rPAL antigen of L. pneumophila, as an effector molecule, activated murine macrophages via TLR2 and produced proinflammatory cytokines such as IL-6 and TNF-alpha. In both BALB/c and TLR4-deficient C3H/HeJ mice, pretreatment of macrophages with anti-TLR2 mAb showed severely impaired cytokine production in response to the rPAL. In addition, in vitro the rPAL treatment increased the cell surface expression of CD40, CD80, CD86 and MHC I/II molecules. We further showed that the synthetic CpG-oligodeoxynucleotides (CpG ODN) coadministered with the rPAL enhanced IL-12 and IL-6 production and expression of CD40, CD80 and MHC II compared to the rPAL treatment alone. In conclusions, these results indicate that Legionella PAL might activate macrophages via a TLR2-dependent mechanism which thus induce cytokine production and expression of costimulatory and MHC molecules.

Lysozyme plays a dual role against the dimorphic fungus Paracoccidioides brasiliensis / A lisozima desempenha um papel duplo contra o fungo dimórfico Paracoccidioides brasiliensis

In order to determine the role of lysozyme, an antimicrobial peptide belonging to the innate immune system, against the dimorphic fungus Paracoccidioides brasiliensis, co-cultures of the MH-S murine alveolar macrophages cell line with P. brasiliensis conidia were done; assays to evaluate the effect of physiological and inflammatory concentrations of lysozyme directly on the fungus life cycle were also undertaken. We observed that TNF-α-activated macrophages significantly inhibited the conidia to yeast transition (p = 0.0043) and exerted an important fungicidal effect (p = 0.0044), killing 27 percent more fungal propagules in comparison with controls. Nonetheless, after adding a selective inhibitor of lysozyme, the fungicidal effect was reverted. When P. brasiliensis propagules were exposed directly to different concentrations of lysozyme, a dual effect was observed. Physiologic concentrations of the enzyme facilitated the conidia-to-yeast transition process (p < 0.05). On the contrary, inflammatory concentrations impaired the normal temperature-dependant fungal transition (p < 0.0001). When yeast cells were exposed to lysozyme, irrespective of concentration, the multiple-budding ability was badly impaired (p < 0.0001). In addition, ultra-structural changes such as subcellular degradation, fusion of lipid vacuoles, lamellar structures and interruption of the fibrilar layer were observed in lysozyme exposed conidia. These results suggest that lysozyme appears to exert a dual role as part of the anti-P. brasiliensis defense mechanisms.

Com a finalidade de determinar o papel da lisozima, um peptídeo antimicrobiano que pertence ao sistema imune inato, contra o fungo dimórfico Paracoccidioides brasiliensis, foram feitas co-culturas de uma linha de macrófagos alveolares murinos (MH-S) com as conídias do fungo na presença ou não do TNF-α e/ou um inibidor da lisozima; também foram feitos ensaios que avaliaram o efeito das concentrações fisiológicas e inflamatórias de lisozima diretamente sobre o ciclo de vida do fungo. Observamos que os macrófagos ativados com a citoquina tiveram um efeito significativo na inibição da transição conídia/levedura (p = 0,0043) e exerceram um efeito fungicida importante (p = 0,0044), matando mais de 27 por cento das propágulas do fungo em comparação com os macrófagos não ativados. No entanto, após ser o inibidor seletivo da lisozima adicionado, o efeito fungicida foi revertido. Quando os propágulos do fungo foram expostos diretamente a diferentes concentrações da lisozima, um duplo efeito foi observado. Assim, as concentrações fisiológicas da enzima facilitaram o processo de transição conídia-levedura (p < 0,05). Contrariamente, as concentrações inflamatórias prejudicaram a transição fúngica (p < 0,0001). Quando as leveduras foram expostas a qualquer concentração de lisozima, sua capacidade de multi-brotação foi gravemente prejudicada (p < 0,0001). Além disso, mudanças ultra-estruturais, como a sub degradação, a fusão dos vacúolos dos lípidos, estruturas lamelares e interrupção da camada fibrilar foram observadas em conídios expostos à lisozima. Estes resultados sugerem que a lisozima poderia exercer um duplo papel no mecanismo antifúngico contra P. brasiliensis.

Activation of macrophages with N-formyl-methionyl-leucyl-phenylalanine: involvement of protein kinase C and tyrosine kinase.

N-formyl-methionyl-leucyl-phenylalanine (fMLP) a potent chemotactic peptide stimulates immune responses by activating macrophages and other cells of the immune system. The present study reports inhibition of fMLP-induced activation of murine peritoneal and P388D-1 macrophage cell line by protein kinase C (PKC) inhibitors, H-7 and chelerythrine chloride. Similarly, tumoricidal activity was also downregulated by protein tyrosine kinase (PTK) inhibitors genestein and lavendustin A. Further, fMLP increased tyrosine phosphorylation of several proteins in murine macrophages, which were inhibited in presence of genestein and lavendustin A. These findings suggest the involvement of PKC and PTK in the activation of murine macrophages with fMLP.

Role of iron in the nitric oxide-mediated fungicidal mechanism of IFN-gamma-activated murine macrophages against Paracoccidioides brasiliensis conidia

Iron is an essential growth element of virtually all microorganisms and its restriction is one of the mechanisms used by macrophages to control microbial multiplication. Paracoccidioides brasiliensis, the agent of paracoccidioidomycosis, an important systemic mycosis in Latin America, is inhibited in its conidia-to-yeast conversion in the absence of iron. We studied the participation of iron in the nitric oxide (NO)-mediated fungicidal mechanism against conidia. Peritoneal murine macrophages activated with 50U/mL of IFN-gamma or treated with 35 æM Deferoxamine (DEX) and infected with P. brasiliensis conidia, were co-cultured and incubated for 96 h in the presence of different concentrations of holotransferrin (HOLO) and FeS0(4). The supernatants were withdrawn in order to assess NO2 production by the Griess method. The monolayers were fixed, stained and observed microscopically. The percentage of the conidia-to-yeast transition was estimated by counting 200 intracellular propagules. IFN-gamma-activated or DEX-treated Mthetas presented marked inhibition of the conidia-to-yeast conversion (19 and 56 percent, respectively) in comparison with non-activated or untreated Mthetas (80 percent). IFN-gamma-activated macrophages produced high NO levels in comparison with the controls. Additionally, when the activated or treated-macrophages were supplemented with iron donors (HOLO or FeSO4), the inhibitory action was reversed, although NO production remained intact. These results suggest that the NO-mediated fungicidal mechanism exerted by IFN-gamma-activated macrophages against P. brasiliensis conidia, is dependent of an iron interaction.

O ferro é elemento essencial para o crescimento de microrganismos e sua limitação é um dos mecanismos usados por macrófagos para controlar a multiplicação microbiana. Paracoccidioides brasiliensis, o agente da paracoccidioidomicose, uma das micoses sistêmicas mais importantes na América Latina, é inibido em sua conversão de conídia-à-levedura na ausência do ferro. Estudamos a participação do ferro no mecanismo fungicida mediado pelo óxido nítrico (NO) na sua interação com as conídias do fungo. Macrófagos peritoneais murinos ativados com 50U/mL de IFN-gama ou tratados com 35 æM Deferoxamina (DEX) e infectados com conídias do P. brasiliensis foram co-cultivados e incubados por 96 h na presença de concentrações diferentes de holotransferrina (HOLO) e FeS0(4). Os sobrenadantes foram retirados a fim de avaliar a produção de NO2 pelo método de Griess. Os macrófagos eram fixados, corados e observados ao microscópio. A porcentagem da transição de conídia-à-levedura foi estimada contando 200 propágulos intracelulares. Os macrófagos ativados com citocina ou tratados com DEX apresentaram inibição marcada da conversão de conídia-à-levedura (19 e 56 por cento, respectivamente) em comparação com macrófagos controle (80 por cento). Os macrófagos ativados com IFN-gama produziram elevação nos níveis de NO em comparação com macrófagos não-tratados ou não-activados. Adicionalmente, quando as monocapas ativadas ou tratadas foram suplementadas com doadores do ferro (HOLO ou FeSO4), a ação inibitória foi revertida embora a produção de NO permanecesse intacto. Estes resultados sugerem que o mecanismo fungicida mediado pelo NO exercido por macrófagos ativados com IFN-gama contra conídias do P. brasiliensis é dependente de uma interação do ferro.

Effect of Sonachandi Chyawanprash and Chyawanprash Plus--two herbal formulations on immunomodulation.

The immunomodulatory effects of Sonachandi Chyawanprash and Chyawanprash Plus--two herbal formulations have been evaluated. Both the drugs increased the macrophage activity and their number indicating enhancement of non-specific immune response and reduction of chances of infection. Besides that both Sonachandi Chyawanprash and Chyawanprash Plus efficiently protected Cyclosporine A induced immunosuppression suggesting the immunoprotective role of the aforesaid herbal formulations.

Comparative effect of ion calcium and magnesium in the activation and infection of the murine macrophage by Leishmania major

Amastigotes of Leishmania major have a great ability to evade destruction in host cells. This study investigated the activation in resident, inflammatory macrophages and J774 cells in vitro treated with lipopolysaccharide (LPS), soluble Leishmania antigen (SLA), calcium ionophore (CaI) and magnesium (Mg2+) alone or combined. An increase in nitric oxide (NO) production was observed in J774 or inflammatory macrophages treated with LPS alone or in combination with SLA and CaI. The same treatments did not affect the NO release by resident macrophages. There was no interference in uptake of L. major but CaI decreased intracellular proliferation of the parasite. This study demonstrated the importance of CaI in decreasing L. major proliferation inside murine macrophages while Mg2+ seemed to increase parasite proliferation. These finding may help to understand the events involved in host cells' clearance of this pathogen..

Soluble factor from tumor cells induces heme oxygenase-1 by a nitric oxide-independent mechanism in murine peritoneal macrophages

Tumor target-derived soluble secretary factor has been known to influence macrophage activation to induce nitric oxide (NO) production. Since heme oxigenase-1 (HO-1) is induced by a variety of conditions associated with oxidative stress, we questioned whether soluble factor from tumor cells induces HO-1 through NO-dependent mechanism in macrophages. We designated this factor as a tumor-derived macrophage-activating factor (TMAF), because of its ability to activate macrophages to induce iNOS. Although TMAF alone showed modest activity, TMAF in combination with IFN-gamma significantly induced iNOS expression and NO synthesis. Simultaneously, TMAF induced HO-1 and this induction was slightly augmented by IFN-gamma. Surprisingly, however, induction of HO-1 by TMAF was not inhibited by the treatment with the highly selective iNOS inhibitor, 1400 W, indicating that TMAF induces the HO-1 enzyme by a NO-independent mechanism. While rIFN-gamma alone induced iNOS, it had no effect on HO-1 induction by itself. Collectively, the current study reveals that soluble factor from tumor target cells induces HO-1 enzyme in macrophages. However, overall biological significance of this phenomenon remains to be determined.

Salmonella. typhi OMPs induced immunomodulation in peritoneal macrophages.

The immunomodulatory properties of outer membrane proteins (OMPs) from S. typhi Ty2 were studied in mouse model at 72 hr and 20 days post-infection. Inspite of reduction in the number of macrophages and their protein content observed in the immunized group vis-à-vis infected group, OMPs activated macrophages showed significant upregulation of NO. At 20 days post infection, the level remained almost the same suggesting the prolonged cytotoxic and cytostatic activity due to the long lasting effects of OMPs activated macrophages. Higher activity of SOD in these aged cells pointed out towards the protective efficacy of OMPs to keep the macrophages themselves away from the noxious effects of O2-. Lower level of acid phosphatase in the macrophages from immunized mice group indicated the involvement of oxygen dependent rather than oxygen independent killing process. The enhanced uptake of organisms and their killing could be related to the production of oxygen and nitrogen radicals in the OMPs immunized group.

Non-cellulosic mixed linkage beta-D-glucan in sorghum, Sorghum bicolor (L.) Moench--localization and biological activity studies.

Fluorescence of Calcofluor and Congo Red was observed in stained sections of sorghum grain (Sorghum bicolor (L.) Moench), especially in the sub-aleurone cells indicating the presence of mixed linkage beta-D-glucan. Relatively less fluorescence intensity was observed in the single layered (approximately 20 microns thick) aleurone. Alkali extracted beta-D-glucan (fraction 2) of sorghum showed 30% activation of rat peritoneal macrophages (in vitro) at 100 micrograms ml-1 concentration in 10 min. This activation was found mediated mainly through PLA2 pathway. A phagocytic index k of 0.102 +/- 0.008 was observed in vivo carbon clearance test in mice in the group treated with fraction 2. Accumulation of colloidal carbon particles in spleen and liver of mice was moderate in this group, compared to control.

Effect of the injection of an extract of Ascaris suum on macrophage activation during the early phase of Mycobacterium bovis BCG infection in C57Bl/6 mice

Injection of an Ascaris suum extract (Asc) affects both the humoral and cellular immune responses to unrelated antigens when it is co-administered with these antigens. In the present study we evaluated the effect of Asc on macrophage activation in the early phase of Mycobacterium bovis BCG (Pasteur strain TMCC 1173) infection in C57Bl/6 mice. C57Bl/6 mice were injected intraperitoneally (ip) with 0.1 mg BCG (BCG group) or BCG plus 1 mg Asc (BCG + Asc group). The peritoneal exudates were obtained at 2, 7 and 14 days after infection. The numbers of IFN-g-secreting cells were assessed by the ELISPOT assay. Nitric oxide (NO) production was measured by the Griess method and by the evaluation of NADPH diaphorase activity in the peritoneal exudates. The administration of Asc extract increased NADPH diaphorase activity (2 days: control = 0, BCG = 7 per cent, BCG + Asc = 13 per cent, and Asc = 4 per cent; 7 days: control = 4, BCG = 13 per cent, BCG + Asc = 21 per cent, and Asc = 4.5 per cent) and TNF-a levels (mean + or - SD; 2 days: control = 0, BCG = 169 + or - 13, BCG + Asc = 202 + or - 37, and Asc = 0; 7 days: control = 0, BCG = 545 + or - 15.5, BCG + Asc = 2206 + or - 160.6, and Asc = 126 + or - 26; 14 days: control = 10 + or - 1.45, BCG = 9 + or - 1.15, BCG + Asc = 126 + or - 18, and Asc = 880 + or - 47.67 pg/ml) in the early phase of BCG infection. Low levels of NO production were detected at 2 and 7 days after BCG infection, increasing at 14 days (mean + or - SD; 2 days: control = 0, BCG = 3.7 + or - 1.59, BCG + Asc = 0.82 + or - 0.005, Asc = 0.48 + or - 0.33; 7 days: control = 0, BCG = 2.78 + or - 1.54, BCG + Asc = 3.07 + or - 1.05, Asc = 0; 14 days: control = 0, BCG = 9.05 + or - 0.53, BCG + Asc = 9.61 + or - 0.81, Asc = 10.5 + or - 0.2 (2 x 106) cells/ml). Furthermore, we also observed that Asc co-injection induced a decrease of BCG-colony-forming units (CFU) in the spleens of BCG-infected mice during the first week of infection (mean + or - SD; 2 days: BCG = 1.13 + or - 0.07 and BCG + Asc = 0.798 + or - 0.305; 7 days: BCG = 1.375 + or - 0.194 and BCG + Asc = 0.548 + or - 0.0226; 14 days: BCG = 0.473 + or - 0.184 and BCG + Asc = 0.675 + or - 0.065 (x 102) CFU). The present data suggest that Asc induces the enhancement of the immune response in the early phase of BCG infection.

Activation of macrophage functions by growth factor present in uterus and embryo extract of pregnant mouse

A pregnant mouse uterus and embryo extract (PMUE) that contains growth hematopoietic factor (M-CSF or CSF-1), was used to test its action on the phagocytic and digestive functions of macrophage. Macrophages incubated with and without PMUE for 24 hours previous to each experiment were compared. A good phagocytosis of Trypanosoma cruzi by macrophages incubated with PMUE, was observed on video microscopy. No phagocytic activity was observed in the macrophages deprived of PMUE 24 hours before. The studies of phagocytic and degradative behavior of macrophages by both soluble and particulated (S. aureus) complex 125I-antibodies showed that total binding of soluble ligands was almost double in the group of macrophages incubated with PMUE. Both the soluble and particulated ligands were digested more efficiently by the macrophages stimulated by PMUE. Counting the macrophages with trypan blue, an equal viability was found, of the cells incubated with and without PMUE. From the experimental data obtained, we may conclude that the hematopoietic growth factor present in PMUE is essential for phagocytic and degradative functions of macrophages.

Release of superoxide anion from activated mouse peritoneal macrophages during Mycobacterium tuberculosis infection.

Mouse peritoneal macrophage monolayers infected with M. tuberculosis were cultured in RPMI up to 7 days. Release of superoxide was assayed on different days in presence or absence of Phorbol myristate acetate (PMA), a known stimulator of NADPH oxidase which is involved superoxide production. Basal level of superoxide release was significantly higher in M. tuberculosis infected peritoneal mouse macrophages (P < 0.01) as compared to normal mouse macrophages. When normal and tuberculoid macrophage cultures were stimulated with PMA, increased superoxide anion release was observed in both the cultures but the increase of superoxide was significantly higher in normal macrophages as compared to tuberculoid stimulated macrophages. Superoxide release was maximum in 4 day old cultured macrophages and gradually it declined in older cultures by day 7, both in vitro and in vivo. A defective macrophage function in killing of M. tuberculosis bacilli was observed after 4 days of in vitro and in vivo cultures.

Canatoxin induces activation on mice peritoneal macrophages

Canatoxin (CNTX), the toxic protein from Canavalia ensiformis seeds, injected into the peritoneal cavities of mice (10 micrograms/cavity) induced a significant neutrophil migration (10.5 +/- 0.5 x 10(6) cells/cavity) after 4 h. A later migratory effect (48 h) on mononuclear cells, predominantly macrophages, was also observed (controls: 7 +/- 0.9; CNTX: 17 +/- 2.0 x 10(6) cells/cavity). These CNTX-elicited macrophages, when compared to resident cells (R) or cells elicited by thioglycollate (TG), had an increased content of the lysosomal enzyme N-acetyl-beta-D-glucosaminidase (R: 4.5 +/- 0.5; TG: 7.2 +/- 1.0; CNTX: 20.2 +/- 3.0 mU/10(6) cells) and a greater (> or = 100%) phagocytic activity. The data suggest that CNTX-stimulated macrophages presented some characteristics of activated cells

Efeitos dos bloqueadores H2 sobre o espraiamento de macrófagos in vitro / Effects of H2 blockers on the spreading of macrophages in vitro

Verificar se a cimetifdina, ranitidina e a famotidina, quando injetadas por via ip em camundongo, promovem ativaçäo macrofágica e se esta é alterada com o uso prévio de tioglicolato sódico. Tipo de estudo - Experimental. Animais - Camundongos isogênicos, Balb/c, 19-21g. Intervençiao - Utilizados oito grupos com 10 animais cada. Os animais foram tratados, por via ip, com cimetidina (100mg/Kg), ranitidina (62,5mg/Kg) e famotidina (50mg/Kg), sendo comparados com um grupo controle (salina). Vinte e quatro horas após a inoculaçäo, foi aplicada a técnica do espraiamento de macrófagos. Em etapa posterior, o mesmo procedimento foi realizado, porém em grupos tratados previamente com tioglicolato sódico (15mg/Kg). Análise estatística - Através dos testes de KrusKal-Wallis e Mann-Whitney. Resultados e conclusäo - A inoculaçäo dos anti-H2 em cavidade peritoneal de camundongos aumenta significantemente o espraiamento macrofágico, independentemente do uso prévio de um irritante peritoneal

Immunotherapeutic modulation of intraperitoneal adhesions by Asparagus racemosus.

The hypothesis that macrophages appear to play a pivotal role in the development of intraperitoneal adhesions and that modulation of macrophage activity, therefore, is likely to provide a tool for prevention of adhesions, was tested in the present study. Effect of Asparagus racemosus, an indigenous agent with immunostimulant properties, was evaluated in an animal model of intraperitoneal adhesions induced by caecal rubbing. Animals were sacrificed 15 days following surgery. The peritoneal macrophages were collected to assess their activity. At the same time, peritoneal cavity was examined for the presence of adhesions, which were graded. A significant decrease was observed in the adhesion scores attained by animals receiving Asparagus racemosus. This was associated with significant increase in the activity of macrophages (70.1 +/- 2.52), compared to that in surgical controls (53.77 +/- 10.8). These findings support our hypothesis and provide a novel approach for the prevention and management of post-operative adhesions.

Desmielinizaçäo tóxica do sistema nervoso central: I. Açäo de uma droga intercalante gliotóxica na medula espinhal de ratos Wistar / Toxic demyelination of the central nervous system: I. Effects of an intercalating gliotoxic chemical in the spinal cord of Wistar rats

Pequenos volumes de brometo de etídio foram injetados nas colunas dorsais da medula lombar de ratos Wistar. Foi assim induzido processo desmielinizante que variou em natureza e velocidade de reparaçäo de acordo com a dose empregada. As lesöes produzidas foram classificadas em três tipos (I, rápidas: II, lentas; III, intermediárias), de acordo com as características histológicas e a extensäo da remielinizaçäo. Em algumas lesöes ou em áreas dentro da mesma lesäo, os restos de mielina e de células eram rapidamente processados por macrófagos e os axônios rapidamente remielinizados por células de Schwann, em quanto em outras lesöes de duraçäo similar, ou em áreas dentro da mesma lesäo, a mielina se transformava em emaranhados de membranas que persistiam ao redor do axônio por longos períodos de tempo. Nas lesöes que continham tais membranas derivadas da mielina, os macrófagos eram escassos e a remielinizaçäo, feita pelas células de Schwann, era demorada e trabalhosa. Concluiu-se que a resoluçäo lenta de algumas lesöes resultara do lapso transcorrido entre a intoxicaçäo e o desaparecimento das células relacionada a mielina, significando que as respostas celulares a desmielinizaçäo tiveram lugar em área livre de células gliais. Esta näo podia sustentar, portnto, a movimentaçäo celular necessária para a remoçäo dos restos de mielina e a posterior remielinizaçäo. Esta investigaçäo indica que o desenvolvimento e o desfecho da desmielinizaçäo podem ser alterados pelos eventos celulares que acompanham a degeneraçäo dos oligodendrócitos