Lactobacillus delbrueckii UFV-H2b20 induces type 1 cytokine production by mouse cells in vitro and in vivo

Lactobacillus delbrueckii UFV-H2b20 has been shown to increase clearance of bacteria injected into the blood of germ-free mice. Moreover, it induces the production of type 1 cytokines by human peripheral mononuclear cells. The objective of the present study was to investigate the production of inflammatory cytokines [interleukin-12 (IL-12 p40), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ)] triggered in vitro by live, heat-killed or lysozyme-treated L. delbrueckii UFV-H2b20 and in vivo by a live preparation. Germ-free, L. delbrueckii-monoassociated and lipopolysaccharide (LPS)-resistant C3H/HeJ mice were used as experimental models. UFV-H2b20 induced the production of IL-12 p40 and TNF-α by peritoneal cells and IFN-γ by spleen cells from germ-free or monoassociated Swiss/NIH mice and LPS-hyporesponsive mice (around 40 ng/mL for IL-12 p40, 200 pg/mL for TNF-α and 10 ng/mL for IFN-γ). Heat treatment of L. delbrueckii did not affect the production of these cytokines. Lysozyme treatment decreased IL-12 p40 production by peritoneal cells from C3H/HeJ mice, but did not affect TNF-α production by these cells or IFN-γ production by spleen cells from the same mouse strain. TNF-α production by peritoneal cells from Swiss/NIH L. delbrueckii-monoassociated mice was inhibited by lysozyme treatment. When testing IL-12 p40 and IFN-γ levels in sera from germ-free or monoassociated Swiss/NIH mice systemically challenged with Escherichia coli we observed that IL-12 p40 was produced at marginally higher levels by monoassociated mice than by germ-free mice (40 vs 60 ng/mL), but IFN-γ was produced earlier and at higher levels by monoassociated mice (monoassociated 4 and 14 ng/mL 4 and 8 h after infection, germfree 0 and 7.5 ng/mL at the same times). These results show that L. delbrueckii UFV-H2b20 stimulates the production of type 1 cytokines in vitro and in vivo, therefore suggesting...

Influences of alpha-tocopherol on cholesterol metabolism and fatty streak development in apolipoprotein E-deficient mice fed an atherogenic diet

Although the role of oxidized lipoproteins is well known in atherogenesis, the role of vitamin E supplementation is still controversial. There is also little information about cholesterol metabolism (hepatic concentration and fecal excretion) in the new models of atherosclerosis. In the present study, we evaluated the effect of moderate vitamin E supplementation on cholesterol metabolism and atherogenesis in apolipoprotein E (apo E)-deficient mice. Apo E-deficient mice were fed an atherogenic diet containing 40 or 400 mg/kg of alpha-tocopherol acetate for 6 weeks. Total cholesterol in serum and liver and 3-OH-alpha-sterols in feces, and fecal excretion of bile acids were determined and histological analyses of aortic lesion were performed. A vitamin E-rich diet did not affect body weight, food intake or serum cholesterol. Serum and hepatic concentrations of cholesterol as well as sterol concentration in feces were similar in both groups. However, when compared to controls, the alpha-tocopherol-treated mice showed a reduction of about 60 percent in the atherosclerotic lesions when both the sum of lesion areas and the average of the largest lesion area were considered. These results demonstrate that supplementation of moderate doses of alpha-tocopherol was able to slow atherogenesis in apo E-deficient mice and to reduce atherogenic lipoproteins without modifying the hepatic pool or fecal excretion of cholesterol and bile acids

Eggplant (Solanum melongena) infusion has a modest and transitory effect on hypercholesterolemic subjects

Eggplant (Solanum melongena) is consumed extensively in Brazil. It has been believed that infusion of a powdered preparation of the fruit may reduce serum cholesterol. However, there are few documented reports on its effects on cholesterol metabolism and its possible hypocholesterolemic effect has not been proved by well-controlled studies. The aim of the present study was to observe the effects of S. melongena on the serum cholesterol and triglycerides of 38 hypercholesterolemic human volunteers ingesting S. melongena infusion for five weeks. Thirty-eight hypercholesterolemic subjects receiving either S. melongena infusion (N = 19) or placebo (N = 19) participated in two clinical experiments in which the effect of S. melongena infusion was studied with (N = 16) or without (N = 38) dietary orientation. Total cholesterol and its fractions, triglycerides, and apolipoproteins A and B were measured in blood at the beginning of the experiment and three and five weeks thereafter. No differences were observed compared to control. Intraindividual analysis showed that S. melongena infusion significantly reduced the blood levels of total and LDL cholesterol and of apolipoprotein B. After dietary orientation, no intra- or intergroup differences were seen for any of the parameters analyzed. The results suggest that S. melongena infusion had a modest and transitory effect, which was not different from that obtained with standard orientation for dyslipidemia patients (diet and physi

Composiçäo de ácidos graxos da gordura na carcaça de frangos de corte sob dietas com diferentes fontes de energia / Carcass fatty acid composition of broiler fed different sources of energy

Avaliaram-se os níveis de energia metabolizável normalmente utilizados nas raçöes de frangos de corte, obtidos pela inclusäo de óleos vegetais (soja, canola e palma) e seus efeitos sobre o perfil de ácidos graxos da pele e dos músculos da coxa e do peito, levando-se em consideraçäo a linhagem e o sexo. Foram utilizados 2400 pintos de um dia, machos e fêmeas, das linhagens comerciais Hubbard e Avian Farms. As aves receberam raçäo inicial e final com níveis de energia metabolízavel de 3050 e 3150kcal/kg, respectivamente, obtidos pela inclusäo dos óleos vegetais, fornecedores de ácidos graxos, inclusive "w-3". Utilizou-se um delineamento inteiramente ao acaso em um arranjo fatorial com 16 tratamentos (4 raçöes x 2 sexos x 2 linhagens) com duas repetiçöes cada. Diferenças entre médias foram testadas pela dms. Näo houve efeito significativo da inclusäo de óleos na raçäo sobre o perfil de ácidos graxos na carcaça. O mesmo ocorreu quanto ao efeito de sexo e de linhagem

Monoassociation with Lactobacillus acidophilus UFV-H2b20 stimulates the immune defense mechanisms of germfree mice

Probiotics are formulations containing live microorganisms or microbial stimulants that have some beneficial influence on the maintenance of a balanced intestinal microbiota and on the resistance to infections. The search for probiotics to be used in prevention or treatment of enteric infections, as an alternative to antibiotic therapy, has gained significant impulse in the last few years. Several studies have demonstrated the beneficial effects of lactic acid bacteria in controlling infection by intestinal pathogens and in boosting the host's nonspecific immune response. Here, we studied the use of Lactobacillus acidophilus UFV-H2b20, a lactic acid bacterium isolated from a human newborn from Viçosa, Minas Gerais, Brazil, as a probiotic. A suspension containing 108 cells of Lactobacillus acidophilus UFV-H2b20 was inoculated into groups of at least five conventional and germfree Swiss mice to determine its capacity to stimulate the host mononuclear phagocytic activity. We demonstrate that this strain can survive the stressing conditions of the intestinal tract in vivo. Moreover, the monoassociation of germfree mice with this strain for seven days improved the host's macrophage phagocytic capacity, as demonstrated by the clearance of a Gram-negative bacterium inoculated intravenously. Monoassociated mice showed an undetectable number of circulating E. coli, while 0.1 percent of the original inoculum was still present in germfree animals. Mice treated with viable or heat-killed Lactobacillus acidophilus UFV-H2b20 presented similarly improved clearance capacity when compared with germfree controls. In addition, monoassociated mice had twice the amount of Kupffer cells, which are responsible for the clearance of circulating bacteria, compared to germfree controls. These results suggest that the L. acidophilus strain used here stimulates a nonspecific immune response and is a strong candidate to be used as a probiotic

Parasitic infections in germfree animals

The association of vertebrate hosts with the indigenous microbiota and its effect on the response to infections has long been a subject of scientific curiosity. From the first theory supported by Louis Pasteur that life would be impossible in the absence of associated microorganisms to the development of germfree mammals for research, a lot was learned about how the normal microbiota influences the environment in which pathogens may find themselves. in the present review, we attempt to summarize the more recent results from our group and others on the influence of the normal microbiota on the outcome of parasitic infections. Our results and those of others point to a complex relationship between the mammalian system and its indigenous microbiota, leading to greater resistance to some infections and enhanced susceptibility to others.

Effect of high ingestion of dehydrated pumklin (Cucurbita pepo L. ) on the cholesterol metabolism and on the hepatic histology in mice

The hypercholesterolemia is one of the most relevant risk factors in atherosclerosis, the latter being responsible for a high mortality in most Western countries. A high intake of foods from plant origin is one of the recommendations for the control of hypercholesterolemia, probably because of their fiber content. This study was designed to evaluate the effects of the ingestion a pumpkin-based diet on cholesterol levels. Fifty mices were divided in three groups: I, animals fed on normocholesterolemic control diet: II, animals fed on a hypercholesterolemic diet; III, animals fed on a hypercholesterolemic diet containing dehydrated pumpkin during 8 weeks. The results showed that dehydrated pumpkin, when administered in high concentration in the diet, reduced the levels of plasmatic and hepatic cholesterol but may caue relevant lesions in liver. Further studies are necessary to evaluate the right proportion of pumpkin to reduce the cholesterolemia without undesirable effects. This study reinforces the need for the continuous support of an experienced histopathologist to detect eventual damage that are not evident on macroscopic examination in all nutritional studies involving tests with diets

Heat or gamma irradiation sterilization affects the hypocholesterolemic effect of guar gum in axenic and heteroxenic rats

1. Twenty-two axenic (germfree) or thirty heteroxenic (axenic colonized with human flora) 2.5-3.5 months old female Fisher rats were fed for four weeks either a hypercholesterolemic (HYPER) diet or a HYPER diet containing 5 per cent guar gum (GG) sterilized by heat or by gamma irradiation. 2. Axenic rats fed the irradiated GG diet had higher cholesterolemia than their counterparts fed an autoclaved diet (4.50 vs 2.29 mmol/l), whereas the method of sterilization had no effect on plasma cholesterol in axenic HYPER or heteroxenic animals (7.35 vs 6.51 mg/dl). 3. The levels of hepatic esterified cholesterol were higher in heteroxenic animals fed the irradiated GG diet than in their counterparts fed the autoclaved GG diet (5.65 vs 3.57 mmol/g tissue). 4. The composition of volatile fatty acids in the cecal content of heteroxenic rats was dependent on the method of sterilization regardless of the presence of fiber: the levels of butyrate were 2.88 and 0.85 mumol/g for rats fed the autoclaved and irradiated diets, respectively. 5. Gamma irradiation abolished the cholesterol-lowering effect of guar gum, whereas sterilization by heat preserved this effect. 6. The hypocholesterolemic effect of guar was reduced by gamma irradiation sterilization and was probably mediated by qualitative changes in the intestinal microflora which interfered with bile acid absorption

Intragastric infection of conventional and germfree mice with Giardia lamblia

The effects of experimental infection with Giardia lamblia were studied in 30-day old conventional and germfree CFW mice (7 animals in each group) of both sexes. Cysts were observed in the feces of both groups 6 to 7 days after intragastric infection of each animal with about 2.5 x 10 5 G. lamblia trophozoites. Fecal cyst level was statisticaly higher in germfree mice (abouth 10 5 cysts/g feces) when compared with the conventional group (about 10 4 cysts/g feces). The peak of infection in the conventional group apparently occurred on the 10th day after infection as indicated by an increase of fecal weight and by histopathological examination. Intense infiltration of the lamina propria and high reactional hyperplasia of the lymphoiud component were observed in the conventional group. There was no infiltration or hyperplasia in germfree infected mice and fecal weight was relatively constant throughout the experiment. These results suggest that, as is the case for other intestinal pathogenic protozoa, the intestinal microflora is indispensable for the expression of the pathogenicity but not for the multiplication of G. lamblia

The acute phase of experimental infection with Trypanosoma cruzi is more severe in mice monoassociated with strict anaerobic bacteria

The influence of some components of the normal human intestinal flora on the acute phase of experimental infection with strain CL of Trypanosoma cruzi was studied in 30-day old germfree or gnotobiotic CFW (LOB) mice monassociated with Bacteroids fragilis, Peptostreptococcus sp or Clostridium sp by intragastrical inoculation of 10 6 bacteria 10 days before the intraperitoneal infections with 5 x 10 3 trypomastigotes/ g body weight. Significantly earlier parasitemia peak and mortality were observed in Bacteroides fragilis and Clostridium-associated mice (16.75 ñ 0.96 and 15.00 ñ 1.15 days, respectively) when compared with germfree animals (18.83 ñ 1.17 days). More precocious mortlity (10.40 ñ 2.06 days) and , curiouslyy, much lower blood parasitemia were observed in Peptostreptococcus-associated mice than in other gnobiotic mice. The extent of cardiac tissue parasitism decreased in the following order: germfree, B. fragilis-associated, Clostridium-associated and Peptostreptococcus associated animals. The levels of inflammatory reaction decreased in the following order: germfree, Peptostreptococcus-associated , Clostridium-associated, and B. fragilis-associated mice. These results show that the acute phase of experimental infection with T. cruzi was more severe in mice associated with strict anaerobic bacteria when compared with germfree animals. This suggests that a normal intestinal flora may be another factor, in addition to nutritional and genetic factors, responsible for the different susceptibility of organisms of the same species infected with T. cruzi

Effect of high sucrose diets on carcass composition in conventional and germ-free mice

1. O efeito da sacarose na dieta sobre a composiçäo da carcassa foi determinado em camundongos convencionais (CV) e isentos de germes (GF) alimentados com raçäo controle e com raçöes contendo 20 a 40% de sacarose. 2. Os camundongos GF na raçäo controle foram mais pesados do que os CV. Contudo, os camundongos CV alimentados com dieta com sacarose foram mais pesados que os GF. 3. Camundongos isentos de germes (GF) alimentados com dieta rica em sacarose mostraram um conteúdo lipídico menor na carcassa em relaçäo aos GF alimentados na raçäo controle e os outros CV. 4. Camundongos convencionais (CV) na dieta rica em sacarose foram mais pesados do que os animais CV na dieta controle. 5. O conteúdo aquoso na carcassa dos camundongos GF na dieta rica em sacarose foi maior do que nos controles GF e nos CV. 6. Esses resultados sugerem um efeito lipidogênico diferente da sacarose alimentar nos camundongos GF e CV

A method for steam-sterilizing semi-solid diets for germ-free mice research

Se describe una ración de maíz semisólida, esterilizada en frascos de vidrio, utilizando un autoclave de tipo hospitalario. Los valores de ganancia de peso, eficacia alimentaria, digestibilidad aparente y diámetro del intestino ciego fueron los mismos para ratones libres de gérmenes, alimentados con esta ración, e con la ración de soya e alfalfa (L-485), ampliamente usada en gnotobiología. La ración de maíz ha sido utilizada con éxito durante un período de ocho años

Immune responses of germfree mice to experimental infection with trypanosoma cruzi

1. The immune responses to Trypanosoma cruzi infection of germfree mice were compared to the reponses of infected conventional mice. Two groups (40 animals in each group) of 2-month old female CFW germfree and vonventional mice were used. The IgM and IgG which bound to the surface of T. cruzi epimastigotes determined by ELISA were significantly lower in germfree than in conventional mice (1/3 and 1/5 for IgM and IgG, respectively). 2. After infection there was a three-fold increase in the circulating levels of these immunoglobulins in germfree but not in conventional mice. twenty-one days after T. cruzi inoculation, both IgG and IgM levels were similar in germfree and conventional animals. 3. Footpad swelling after T. cruzi-antigen inoculation was initially four-fold more intense in germfree than in conventional mice. 4. These results suggest that the reduced humoral immune response of germfree mice during ythe initiation of experimental Chagas' disease may be responsible for the more severe parasitism when compared to conventional mice

Intragastric infection of germfree and conventional mice with Salmonella typhimurium

The present study investigates the lethality of intragastric Salmonella typhimurium infection of germfree (GF) and conventional (CV, not germfree) mice. The introduction of only 10 viable S. typhimurium into the gastrointestinal tract of GF mice resulted in death of all animals within 8 days of inoculation. In contrast, the 50% lethal dose for CV mice was 4.7 x 10**3 viable organisms. The results demonstrate that resident microbes protect mice from the pathogenic effect of S. typhimurium infection

The association of Schistosoma mansoni infection with deficiency of vitamin A in mice.

Verificou-se que o desenvolvimento somatico do Schistosoma mansoni foi retardado em camundongos com deficiencia de vitamina A, quando comparado com aquele obtido no grupo controle. A diferenca foi mais acentuada no 12o. dia. A proporcao de vermes no 1o., 2o. e 3o. estagios de desenvolvimento foi de 66,5%; 31,0 e 2,5%, respectivamente, para os camundongos em avitaminose A, e 26,4; 37,4 e 36,2%, respectivamente, para os controles. No 18o. dia apos a exposicao cercariana, a proporcao de vermes no 1o., 2o., 3o., 4o. e 5o. estagios foi de 4,4; 0,0%; 46,45; 36,44 e 12,66% para os camundongos com deficiencia de vitamina A, e 0,0; 0,0; 17,54; 54,84 e 27,62%, respectivamente, para os controles. A oviposicao foi praticamente a mesma em ambos os grupos. Nao foi possivel detectar caroteno ou vitamina A nos vermes obtidos de animais em avitaminose A. Nos esquistossomos recuperados de animais-controles, os niveis de caroteno e vitamina A foram 1020 e 0,086 microgramo/g de verme, respectivamente.Alguns animais desenvolveram uma neuropatia, com consequente amputacao espontanea de uma das patas dianteiras. Nos grupos controle e dificientes de vitamina A infectados, a incidencia desta neuropatia foi de 4,9 e 23,1% respectivamente