Occurrence of Toxoplasma gondii and risk factors for infection in pigs raised and slaughtered in the Triângulo Mineiro region, Minas Gerais, Brazil / Ocorrência e fatores de risco da infecção por Toxoplasma gondii em suínos criados e abatidos na região do Triângulo Mineiro, Minas Gerais, Brasil

The Triângulo Mineiro region from Minas Gerais state, is an important meat-exporting region of Brazil and data about Toxoplasma gondii infection in pigs raised and slaughtered in this area are scarce. Therefore, the aim of this study was to evaluate the occurrence of T. gondii in swine and establish the risk factors associated with the infection. Samples were collected from 600 pigs raised under intensive system in farms located at three different counties (Carmo do Paranaíba, Patrocínio and Perdizes). The samples were submitted to indirect hemagglutination antibody test with dilution of 1:32 and to indirect immunofluorescence antibody test with a cutoff of 1:64. The occurrence of positive pig was 3.3% (n=20) and 51.8% (n=311) respectively. A significant difference was observed between toxoplasmatic infection and factors such as lineage, animal origin, size of the farm, collective raising with others species, presence of rodents and type of water offered (p≤0.05). There was no difference between gender and the farm goals. The results demonstrated an occurrence of anti-T.gondii antibodies higher than expected for intensive pig raising system on the studied area, which could indicate a possible sanitary management problem on the studied proprieties. Improvements on the raising techniques are necessary to reduce T. gondii infection sources.(AU)

A região do Triângulo Mineiro, no estado de Minas Gerais, é uma importante região exportadora de carne do Brasil e pesquisas sobre a infecção por Toxoplasma gondii em suínos criados e abatidos nesta região são escassos. Portanto, o objetivo deste estudo foi avaliar a ocorrência de T. gondii nesses animais e estabelecer os fatores de risco associados com a infecção. Foram coletadas amostras de 600 suínos criados sob sistema intensivo, em fazendas localizadas em três municípios diferentes (Carmo do Paranaíba, Patrocínio e Perdizes). As amostras foram submetidas à Hemaglutinação Indireta com diluição de 1:32 e à Reação de Imunofluorescência Indireta com ponto de corte 1:64. A ocorrência de suínos positivos foi de 3,3% (n=20) e 51,8% (n=311), respectivamente. Foi observada diferença significativa entre a infecção toxoplásmica e fatores como linhagem, procedência dos animais, tamanho das propriedades, criação em conjunto com outras espécies, presença de roedores e tipo de água consumida (p≤0,05). Não houve diferenças estatísticas entre o sexo e finalidade de produção em relação à infecção por T. gondii. Os resultados demonstraram uma ocorrência de anticorpos anti-T. gondii superior à esperada em criações intensivas de suínos na região estudada, o que poderia indicar uma possível falha no manejo sanitário das propriedades estudadas. Melhorias nas técnicas de criação são necessárias para redução das fontes de infecção por T. gondii nos rebanhos.(AU)

Apoptotic signaling pathways induced by acute administration of branched-chain amino acids in an animal model of maple syrup urine disease.

Maple Syrup Urine Disease (MSUD) is an inborn error of metabolism caused by a deficiency of the branched-chain α-keto acid dehydrogenase complex activity. This blockage leads to accumulation of the branched-chain amino acids leucine, isoleucine and valine, as well as their corresponding α-keto acids and α-hydroxy acids. The affected patients present severe neurological symptoms, such as coma and seizures, as well as edema and cerebral atrophy. Considering that the mechanisms of the neurological symptoms presented by MSUD patients are still poorly understood, in this study, protein levels of apoptotic factors are measured, such as Bcl-2, Bcl-xL, Bax, caspase-3 and -8 in hippocampus and cerebral cortex of rats submitted to acute administration of branched-chain amino acids during their development. The results in this study demonstrated that BCAA acute exposure during the early postnatal period did not significantly change Bcl-2, Bcl-xL, Bax and caspase-8 protein levels. However, the Bax/Bcl-2 ratio and procaspase-3 protein levels were decreased in hippocampus. On the other hand, acute administration of BCAA in 30-day-old rats increase in Bax/Bcl-2 ratio followed by an increased caspase-3 activity in cerebral cortex, whereas BCAA induces apoptosis in hippocampus through activation and cleavage of caspase-3 and -8 without changing the Bax/Bcl-2 ratio. In conclusion, the results suggest that apoptosis could be of pivotal importance in the developmental neurotoxic effects of BCAA. In addition, the current studies also suggest that multiple mechanisms may be involved in BCAA-induced apoptosis in the cerebral cortex and hippocampus.

Acute brain inflammation and oxidative damage are related to long-term cognitive deficits and markers of neurodegeneration in sepsis-survivor rats.

Survivors from sepsis present long-term cognitive deficits and some of these alterations resemble the pathophysiological mechanisms of neurodegenerative diseases. For this reason, we analyzed beta-amyloid peptide (Aß) and synaptophysin levels in the brain of rats that survived from sepsis and their relation to cognitive dysfunction and to acute brain inflammation. Sepsis was induced in rats by cecal ligation and puncture, and 30 days after surgery, the hippocampus and prefrontal cortex were isolated just after cognitive evaluation by the inhibitory avoidance test. The immunocontent of Aß and synaptophysin were analyzed by Western blot analysis. Aß increased and synaptophysin decreased in septic animals both in the hippocampus and prefrontal cortex concurrent with the presence of cognitive deficits. Prefrontal levels of synaptophysin correlated to the performance in the inhibitory avoidance. Two different treatments known to decrease brain inflammation and oxidative stress when administered at the acute phase of sepsis decreased Aß levels both in the prefrontal cortex and hippocampus, increased synaptophysin levels only in the prefrontal cortex, and improved cognitive deficit in sepsis-survivor animals. In conclusion, we demonstrated that brain from sepsis-survivor animals presented an increase in Aß content and a decrease in synaptophysin levels and cognitive impairment. These alterations can be prevented by treatments aimed to decrease acute brain inflammation and oxidative stress.

Acute exercise induce endothelial nitric oxide synthase phosphorylation via Akt and AMP-activated protein kinase in aorta of rats: Role of reactive oxygen species.

BACKGROUND: Acute exercise increases reactive oxygen species (ROS) levels, including hydrogen peroxide (H2O2). H2O2 promotes endothelial nitric oxide synthase (eNOS) activation and phosphorylation in endothelial cells. With this in mind, the present study was designed to evaluate ex vivo eNOS phosphorylation in rat aortas incubated with H2O2 and to test this hypothesis in vivo in the aortas of rats submitted to acute exercise. METHODS: For ex vivo studies, six groups of aortic tissue were formed: control, H2O2, N-acetylcysteine (NAC), LY294002, compound C, and LY294002 plus compound C. While incubation with H2O2 increased Akt, AMPK and eNOS phosphorylation, pre-incubation with NAC strongly reduced the phosphorylation of these enzymes. For in vivo studies, male Wistar rats were divided into four groups: control, cont+NAC, exercise, and exer+NAC. After a 3h swimming session, animals were decapitated and aortas were excised for biochemical and immunoblotting analysis. RESULTS: Acute exercise increased superoxide levels and dichlorofluorescein (DCF) concentrations, and this increase was related to phosphorylation of Akt, AMPK and eNOS. On the other hand, use of NAC reduced superoxide levels and DCF concentration. Reduced superoxide levels and DCF in the exer+NAC group were associated with decreased Akt, AMPK and eNOS phosphorylation. These results appear to be connected with vascular function because VASP phosphorylation increased in acute exercise and decreased in exer+NAC. CONCLUSION: Our results indicate that ROS induced by acute exercise play the important role of activating eNOS, a process apparently mediated by Akt and AMPK.

Phytochemical screening, antinociceptive and anti-inflammatory activities of Chrysopogon zizanioides essential oil

Chrysopogon zizanioides (L.) Roberty, Poaceae, is a plant widely used in northeast Brazil in folk medicine for the treatment of various pathological conditions, including inflammatory pain. The present study evaluated the antinociceptive and anti-inflammatory effects of C. zizanioides essential oil (EO) in rodents. EO was further characterized by GC/MS. The major components of EO were identified as khusimol (19.57%), E-isovalencenol (13.24%), α-vetivone (5.25%), β-vetivone (4.87%) and hydroxy-valencene (4.64%). Following intraperitoneal injection (i.p.), EO at 50 and 100 mg/kg significantly reduced the number of writhes (51.9 and 64.9%, respectively) and the number of paw licks during phase 2 (56.7 and 86.2%, respectively) of a formalin model when compared to control group animals. However, EO-treated mice were ineffective at all doses in hot-plate and rota-rod tests. The EO inhibited the carrageenan-induced leukocyte migration to the peritoneal cavity in a dose-dependent manner (34.7, 35.4, and 62.5% at doses of 25, 50 and 100 mg/kg, respectively). In the paw edema test, the EO (100 mg/kg) inhibited all three phases of the edema equally well, suggesting that the EO has a non-selective inhibitory effect on the release or actions of these mediators. Our results suggest possible antinociceptive and anti-inflammatory effects of the EO.

Bioassay-guided evaluation of antioxidant and antinociceptive activities of carvacrol.

We examined the antioxidant properties in vitro and the antinociceptive effect of carvacrol (CARV) in several models of pain in mice. CARV presented a strong antioxidant potential according to the TRAP/TAR evaluation; it also presented scavenger activity against nitric oxide and prevented lipid peroxidation in vitro. In mice, when evaluated against acetic acid-induced abdominal writhing, CARV (25, 50 and 100 mg/kg, i.p.) reduced (p < 0.001) the number of writhing compared to the control group, without opioid participation. In the formalin test, CARV also significantly inhibited both the early (neurogenic pain) and the late (inflammatory pain) phases of formalin-induced licking, with inhibition percentage values of 56.8% (100 mg/kg) for the neurogenic phase and 41.2% (25 mg/kg), 73.8% (50 mg/kg) and 99.7% (100 mg/kg) for the inflammatory phase. CARV also produced a significant inhibition of the pain caused by capsaicin (63.1, 67.1 and 95.8%, p < 0.001) and glutamate (46.4, 61.4 and 97.9%, p < 0.01). When assessed in a thermal model of pain, CARV (100 mg/kg, i.p.) caused a significant increase (p < 0.05) in the latency response on the hot-plate test. Such results were unlikely to be provoked by motor abnormality. Together, these results indicate that the properties of CARV should be more thoroughly examined in order to achieve newer tools for management and/or treatment of painful conditions, including those related to pro-oxidant states.