Mild cognitive deficits associated to neocortical microgyria in mice with genetic deletion of cellular prion protein

The cellular prion protein (PrP(c)) has been implicated with the modulation of neuronal apoptosis, adhesion, neurite outgrowth and maintenance which are processes involved in the neocortical development. Malformations of cortical development (MCD) are frequently associated with neurological conditions including mental retardation, autism, and epilepsy. Here we investigated the behavioral performance of female adult PrP(c)-null mice (Prnp(%)) and their wild-type controls (Prnp(+/+)) presenting unilateral polymicrogyria, a MCD experimentally induced by neonatal freeze-lesion in the right hemisphere. injured mice from both genotypes presented similar locomotor activity but Prnp(%) mice showed a tendency to increase anxiety-related responses when compared to Prnp(+/+) animals. Additionally, injured Prnp(%) mice have a poorer performance in the social recognition task than sham-operated and Prnp(%) injured ones. Moreover the step-down inhibitory avoidance task was not affected by the procedure or the genotype of the animals. These data suggest that the genetic deletion of PrP(c) confers increased susceptibility to short-term social memory deficits induced by neonatal freezing model of polymicrogyria in mice. (C) 2008 Published by Elsevier B.V.

Transient disruption of liver gap junctional intercellular communication and induction of apoptosis after administration of 1,4-bis[2-(3,5 dichloropyridyloxy)]benzene in mice

Gap junctional intercellular communication (GJIC) and connexin expression (Cx26 and Cx32) in mouse liver were studied after administration of 4-bis[2-(3,5 dichloropyridyloxy)]benzene (TCPOBOP), a phenobarbital-like enzyme inducer. Female C57BI/6 mice were administered TCPOBOP (5.8 mg/kg BW) and euthanized 0, 24, 48 and 72 hours later. Liver samples were snap frozen, or fixed in formalin, or submitted to GJIC analysis. The proliferating cell nuclear antigen (PCNA) immunohistochemistry and the Western blotting for Cx26 and Cx32 were performed. After 48 and 72 h of drug administration the liver-to-body weight ratio was increased 70% and 117% (p < 0.0001), respectively. There were temporal-dependent alterations in liver histopathology and a significant increase in cell proliferation was noted after 48h and sustained after 72h, though to a lesser extent (p < 0.0001). In addition. TCPOBOP administration induced apoptosis, which appeared to be time-dependent showing statistical significance only after 72h (p < 0.0001). Interestingly, a transient disruption by nearly 50% of GJIC capacity was detected after 48 h of drug ingestion, which recovered after 72 h (p = 0.003). These GJIC changes were due to altered levels of Cx26 and Cx32 in the livers of TCPOBOP-treated mice. We concluded that a single administration of TCPOBOP transiently disrupted the levels of GJIC due to decreased expression of connexins and increased apoptotic cell death in mouse liver. (C) 2009 Elsevier GmbH. All rights reserved.

Anandamide prior to sensitization increases cell-mediated immunity in mice

The endocannabinoid system has become a topic of great interest in pharmacology due to its remarkable distribution in mammal organisms and capacity to play a modulatory role on several physiological systems, including modulation of immunity. Many studies have shown that administration of cannabinoids causes inhibitory effects on immune cells, including decreased proliferation and antigen-presenting cell (APC) costimulatory activity. In contrast, other groups have shown that some cannabinoids might present stimulatory actions on macrophage activity and T cell activation. Therefore, we aimed to investigate whether a treatment in vivo with a low dose of anandamide (0.1 mg/kg) immediately prior to sensitization would have an immunosuppressive or immunostimulatory effect on cell-mediated immunity (Th1 response) in mice. We report here that anandamide, prior to sensitization, was able to increase the Th1 response to ovalbumin in vivo and ex vivo. Anandamide increased delayed type hypersensitivity (DTH), splenocyte proliferation, and IFN-gamma production in a co-culture of adherent and non-adherent splenocytes. Moreover, anandamide prior to sensitization increased both the expression of DC co-stimulatory molecules (CD80/CD86) and IL-12/IL23 (p40) production ex vivo. We have also assessed direct effects of anandamide in the IFN-gamma/IL-4 balance of ConA-stimulated splenocytes in vitro. Anandamide at nanomolar concentrations increased the production of IFN-gamma, while such production decreased at micromolar range. Thus, anandamide induced both the increment of DC activation and IFN-gamma production, which are likely the mechanisms involved in the increase of Th1 response reported here. (C) 2010 Elsevier B.V. All rights reserved.

Protective action of indole-3-acetic acid on induced hepatocarcinoma in mice

In this study, we report the protective effects of IAA on diethylnitrosamine (DEN)-induced hepatocarcinogenesis. BALB/c mice received daily IAA at 50 (T(50)), 250 (T(250)), and 500 (T(500)) mg K(-1) per body mass by gavage for 15 days. At day 15, animals were administered DEN and sacrificed 4 h later. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were analyzed in sera. In addition., hepatomorphologic alterations, activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR), gene expression of antioxidant enzymes and DNA integrity were evaluated in the liver. IAA administration did not show any alterations in any of the parameters available, except for a reduction of the gene expression for antioxidant enzyrries by 55, 56, 27, and 28% for SOD, CAT, GPx, and GR upon T(500). respectively compared with the control. Several hepatic alterations were observed by DEN exposure. Moreover, IAA administration at 3 doses was shown to provide a total prevention of the active reduction of CAT and GR induced by DEN exposure compared with the control. IAA at T5(00) was shown to give partial protection (87, 71, 57, and 90% for respectively SOD, CAT. GPx. and GR) on the down-regulation of the enzymes induced by DEN and this auxin showed a partial protection (50%) on DEN-induced DNA fragmentation for both parameters when compared to DEN alone. This work showed IAA hepatocarcinogenesis protection for the first time by means of a DEN-protective effect on CAT and GR activity. and by affecting antioxidant gene expression and DNA fragmentation. Copyright (C) 2008 John Wiley & Sons, Ltd.

Effects of individual housing on behavior and resistance to Ehrlich tumor growth in mice

This study analyzed in Balb/C mice the effects of individual housing on behavior, serum corticosterone and resistance to Ehrlich tumor growth. Mice (60 days old) were individually (IH) or grouped housed (G) (10-12 animals/cage) for 14-21 days. The 1st day of the housing condition was considered experimental day 1 (ED1). Results showed that on ED21, IH mice, when compared to G mice, presented no differences on corticosterone serum levels when kept undisturbed; however, an increased level of this hormone was observed in IH mice after an immobilization stress challenge. An increased time spent in the plus-maze closed arms and a decreased time in the open arms were also observed in IH mice. When compared to G animals, after inoculation with 105 Ehrlich tumor cells on ED1, IH mice presented an increase in volume of ascitic fluid and number of tumor cells. The survival time of IH mice was also shorter than that measured in G animals. Furthermore, IH mice injected with a different number of tumor cells on ED1 always presented increased Ehrlich tumor cells than G group. Interestingly. these effects were not observed when the tumor cells injection was done on ED4. These results suggest that individual-housing conditions induce an altered immune-endocrine response and, at the same time, decrease animals` resistance to Ehrlich tumor growth. It is proposed that the neural link between the behavioral and immunological changes observed after the stress of individual housing might involve the activation of the HPA axis. (C) 2008 Elsevier Inc. All rights reserved.

Neuroendocrine, behavioral and macrophage activity changes induced by picrotoxin effects in mice

The relevance and property of studies related to stress effects on immune function are undisputable. All studies conducted on stress-immune relationships, however, provide from physical and/or psychological stressors. Indeed, as far as it is of our knowledge brain-innate immune responses were not analyzed after anxiogenic-like drugs use. The present experiment was then undertaken to analyze the effects of picrotoxin (0.3, 0.6 and 1.0 mg/kg doses) on behavior, macrophage activity, serum corticosterone and noradrenaline (NE) levels and turnover in the brain of adult mice. Results showed that picrotoxin treatment in mice: (1) decreased motor and rearing activities in an open-field; (2) decreased the number of entries into the plus-maze open-arms and decreased the time spent in the exploration of the plus-maze open-arms; (3) decreased both motor activity and the level of holes exploration in the hole-board; (4) increased the levels of serum corticosterone in dose-dependent way; (5) increased noradrenaline (NE) and MHPG levels and NE turnover in the hypothalamus; and (6) increased Staphylococcus aureus and PMA-induced macrophage oxidative burst. However, and contrary to that reported after physical or psychological stress, this drug induced no effects on macrophage phagocytosis and NE levels and turnover in the frontal cortex. The present results are thus showing that picrotoxin induces some but not all neuro-innate immunity changes previously reported for inescapable foot-shock and psychological stressors in mice. These facts suggest that this chemical stressor triggers CNS pathways that might be somehow different from those fired by inescapable foot-shock and psychological stressors, leading to different neuro-innate immune responses. (C) 2007 Elsevier Ltd. All fights reserved.

Differential Shh, Bmp and Wnt gene expressions during craniofacial development in mice

In this study, Bmp-4, Wnt-5a and Shh gene expressions were compared during early craniofacial development in mice by comparative non-isotopic in situ hybridization. Wild-type C57BL/6J mice were studied at various stages of embryonic development (from 8.5- to 13.5-day-old embryos - E8.5-13.5). During early odontogenesis, transcripts for Bmp-4, Shh and Wnt-5a were co-localised at the tooth initiation stage. At E8.5, Shh mRNA expression was restricted to diencephalon and pharyngeal endoderm. Before maxillae and mandible ossification, Bmp-4 and Wnt-5a signals were detected in the mesenchymal cells and around Meckel`s cartilage. During palatogenesis, Shh was expressed only in the epithelium and Wnt-5a only in the mesenchyme of the elevating palatal shelves. During tongue development, Shh expression was found in mesenchyme, probably contributing to tongue miogenesis, while Wnt-5a signal was in the epithelium, possibly during placode development and papillae formation. Taken together, these findings suggest that Bmp-4, Shh and Wnt-5a gene expressions may act together on the epithelial mesenchymal interactions occurring in several aspects of the early mouse craniofacial development, such as odontogenesis, neuronal development, maxillae and mandible ossification, palatogenesis and tongue formation. (C) 2009 Elsevier GmbH. All rights reserved.

The essential role of toll like receptor-4 in the control of Aggregatibacter actinomycetemcomitans infection in mice

Objective: Aggregatibacter actinomycetemcomitans is an oral Gram-negative bacterium that contributes to periodontitis progression. Isolated antigens from A. actinomycetemcomitans could be activating innate immune cells through Toll-like receptors (TLRs). In this study, we evaluated the role of TLR4 in the control of A. actinomycetemcomitans infection. Material and Methods: We examined the mechanisms that modulate the outcome of A. actinomycetemcomitans-induced periodontal disease in TLR4(-/-) mice. The production of cytokines was evaluated by ELISA. The bacterial load was determined by counting the number of colony-forming units per gram of tissue. Results: The results showed that TLR4-deficient mice developed less severe periodontitis after A. actinomycetemcomitans infection, characterized by significantly lower bone loss and inflammatory cell migration to periodontal tissues. However, the absence of TLR4 facilitated the A. actinomycetemcomitans dissemination. Myeloperoxidase activity was diminished in the periodontal tissue of TLR4(-/-) mice. We observed a significant reduction in the production of tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1 beta in the periodontal tissue of TLR4(-/-) mice. Conclusion: The results of this study highlighted the role of TLR4 in controlling A. actinomycetemcomitans infection.

Influence of Genetic Background on Fluoride Metabolism in Mice

A/J and 129P3/J mouse strains have different susceptibilities to dental fluorosis, due to their genetic backgrounds. This study tested whether these differences are due to variations in water intake and/or F metabolism. A/J (susceptible to dental fluorosis) and 129P3/J mice (resistant) received drinking water containing 0, 10, or 50 ppm F. Weekly F intake, excretion and retention, and terminal plasma and femur F levels were determined. Dental fluorosis was evaluated clinically and by quantitative fluorescence (QF). Data were tested by two-way ANOVA. Although F intakes by the strains were similar, excretion by A/J mice was significantly higher due to greater urinary F excretion, which resulted in lower plasma and femur F levels. Compared with 129P3/J mice given 50 ppm F, significantly higher QF scores were recorded for A/J mice. In conclusion, these strains differ with respect to several features of F metabolism, and amelogenesis in the 129P3/J strain seems to be unaffected by high F exposure.

Deficiency of IL-12p40 subunit determines severe paracoccidioidomycosis in mice

Paracoccidioidomycosis, the major systemic mycosis in Latin America, is caused by the thermally dimorphic fungus Paracoccidioides brasiliensis. To investigate the role of interleukin (IL)-12 in this disease, IL-12p40(-/-) deficient mice (IL-12p40(-/-)) and wild type mice (WT) were infected intravenously with viable yeast cells of P. brasiliensis 18 isolate. We found that, unlike WT mice, IL-12p40(-/-) mice did not control fungal proliferation and dissemination and succumbed to infection by day 21 after inoculation. Additionally, IL-12p40(-/-) mice presented a higher number of granulomas/mm(2) in lung tissue than WT mice, and showed unorganized granulomas containing high numbers of yeast cells. Moreover, IL-12p40(-/-) mice did not release detectable levels of IFN-gamma, but they produced high levels of IL-10, as well as IgG1 antibody. Additionally, splenocytes from both infected IL-12p40(-/-) and WT mice exhibited a suppressed Con-A-induced T cell proliferative response. Our findings suggest that the IL-12p40 subunit mediates resistance in paracoccidioidomycosis by inducting IFN-gamma production and a Th1 immune response

Exposure to ambient levels of particles emitted by traffic worsens emphysema in mice

Objectives: We investigated effects of chronic exposure (2 months) to ambient levels of particulate matter (PM) on development of protease-induced emphysema and pulmonary remodeling in mice. Methods: Balb/c mice received nasal drop of either papain or normal saline and were kept in two exposure chambers situated in an area with high traffic density. One of them received ambient air and the other had filters for PM. Results: mean concentration of PM10 was 2.68 +/- 0.38 and 33.86 +/- 2.09 mu g/m(3), respectively, in the filtered and ambient air chambers (p<0.001). After 2 months of exposure, lungs from papain-treated mice kept in the chamber with ambient air presented greater values of mean linear intercept, an increase in density of collagen fibers in alveolar septa and in expression of 8-isoprostane (p = 0.002, p < 0.05 and p = 0.002, respectively, compared to papain-treated mice kept in the chamber with filtered air). We did not observe significant differences between these two groups in density of macrophages and in amount of cells expressing matrix metalloproteinase-12. There were no significant differences in saline-treated mice kept in the two chambers. Conclusions: We conclude that exposure to urban levels of PM worsens protease-induced emphysema and increases pulmonary remodeling. We suggest that an increase in oxidative stress induced by PM exposure influences this response. These pulmonary effects of PM were observed only in mice with emphysema. (C) 2009 Elsevier Inc. All rights reserved.

Oxidative stress and inflammatory mediators contribute to endothelial dysfunction in high-fat diet-induced obesity in mice

Objective We investigated the effects of high-fat diet-induced obesity on vascular proinflammatory factors and oxidative stress on endothelium-dependent relaxation of the aorta. Methods Female Swiss mice were submitted to a high-fat diet for 16 weeks. At the end of the experimental period, we evaluated blood pressure, relaxation in response to acetylcholine in aortic rings in the absence and the presence of the superoxide anion scavenger, superoxide dismutase (SOD, 150 U/ml), and the nuclear factor (NF)-kappa B inhibitor, sodium salicylate (5 mmol/l). Aortic protein expression of endothelial nitric oxide synthase, Cu/Zn-SOD, NF-kappa B, I kappa B-alpha, and proinflammatory cytokines were also evaluated. Results Obese mice presented higher systolic and diastolic blood pressure than control mice (P<0.05). The relaxation of aortas to acetylcholine, but not to sodium nitroprusside, was significantly decreased in obese mice and was corrected by both SOD and sodium salicylate (P<0.05). The protein expression of endothelial nitric oxide synthase and Cu/Zn-SOD was significantly decreased in aorta from obese mice (P<0.05). Total p65 NF-kappa B subunit protein expression was not affected by obesity, but the protein expression of NF-kappa B inhibitor I kappa B-alpha was lower in aorta from obese mice (P<0.05). There were no significant differences in the interleukin (IL)-1 beta and IL-6 protein expression between groups. In contrast, the expression of TNF-alpha was significantly increased in aortas from obese mice. Conclusion Our resultssuggest that the reducedantioxidant defense and the local NF-kappa B pathway play an important role in the impairment of endothelium-dependent relaxation in aorta from obese mice. J Hypertens 28: 2111-2119 (C) 2010 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.

Expression Patterns of Cell Adhesion Molecules in Mice`s Lung After Administration of Meso-2,3-Dimercaptosuccinic Acid-Coated Maghemite Nanoparticles

We studied the expression pattern of cell adhesion molecules associated to transendothelial migration of leukocytes in different lung`s vascular compartments after administration of a magnetic fluid sample containing maghemite nanoparticles surface-coated with meso-2,3-dimercaptosuccinic acid. The analyses were conducted in mice 4 and 12 h after endovenous administration of the magnetic fluid in control mice. Firstly, the migratory activity of leukocytes after magnetic fluid surface-coated with meso-2,3-dimercaptosuccinic acid administration was confirmed using broncho-alveolar lavage and light microscopy. Then, the expression of cell adhesion molecules in the lung`s vascular compartments was investigated by immunofluorescence microscopy of frozen sections, using antibodies against L-selectin, P-selectin, E-selectin, macrophage antigen-1, and leukocyte function associated antigen-1. L- and P-selectin showed similar pattern of expression in the pulmonary vasculature in animals treated with magnetic fluid and in the control group. In contrast, macrophage antigen-1 and leukocyte function associated antigen-1 were found in capillary only in animals treated with magnetic fluid surface-coated with meso-2,3-dimercaptosuccinic acid administration. In addition, after magnetic fluid administration E-selectin was found in post-capillary sites. Our findings demonstrated that magnetic fluid surface-coated with meso-2,3-dimercaptosuccinic acid administration exhibits modulation effects on expression patterns of E-selectin, macrophage antigen-1, and leukocyte function associated antigen-1 in the lung`s vascular compartments. These findings are very important in a strategy to reduce the potential toxicity of magnetic fluid surface-coated with meso-2,3-dimercaptosuccinic acid administration for medical applications.

In vivo hydroquinone exposure alters circulating neutrophil activities and impairs LPS-induced lung inflammation in mice

Hydroquinone (HQ) is an environmental contaminant which causes immune toxicity. In this study, the effects of exposure to low doses of HQ on neutrophil mobilization into the LPS-inflamed lung were investigated. Male Swiss mice were exposed to aerosolized vehicle (control) or 12.5, 25 or 50 ppm HQ (1 h/day for 5 days). One hour later, oxidative burst, cell cycle. DNA fragmentation and adhesion molecules expressions in circulating neutrophils were determined by flow cytometry, and plasma malondialdehyde (MDA) levels were measured by HPLC. Also, 1 h later the last exposures, inflammation was induced by LPS inhalation (0.1 mg/ml/10 min) and 3 h later, the numbers of leukocytes in peripheral blood and in the bronchoalveolar lavage fluid (BALF) were determined using a Neubauer chamber and stained smears; adhesion molecules expressed on lung microvessel endothelial cells were quantified by immunohistochemistry; myeloperoxidase (MPO) activity was measured in the lung tissue by colorimetric assay; and cytokines in the BALF were determined by ELISA. In vivo HQ exposure augmented plasma MDA levels and oxidative activity of neutrophils, but did not cause alterations in cell cycle and DNA fragmentation. Under these conditions, the number of circulating leukocytes was not altered, but HQ exposure reduced LPS-induced neutrophil migration into the alveolar space, as these cells remained in the lung tissue. The impaired neutrophil migration into BALF may not be dependent on reduced cytokines secretions in the BALF and lung endothelial adhesion molecules expressions. However, HQ exposure increased the expression of beta(2) and beta(3) integrins and platelet-endothelial cell adhesion molecule-1 (PECAM-1) in neutrophils, which were not further enhanced by fMLP in vitro stimulation, indicating that HQ exposure activates circulating neutrophils, impairing further stimulatory responses. Therefore, it has been shown, for the first time, that neutrophils are target of lower levels of in vivo HQ exposure, which may be considered in host defense in infectious diseases. (C) 2011 Elsevier Ireland Ltd. All rights reserved.