Studies evaluating the toxicity caused by fungal exopolysaccharides of the β-(1→6)-d-glucan type are rare. In this study, the toxicological effects of sub-chronic treatments with lasiodiplodan (β-(1→6)-d-glucan from Lasiodiplodia theobromae MMPI) were evaluated in mice through the assessment of biochemical, hematological, and histopathological alterations. Thirty-two mice (16 male, 16 female) were used in this study divided in two groups; one group received lasiodiplodan (50 mg/kg body weight) daily for 28 days via gavage, and another (control group) received saline during the same period. Blood samples were collected via cardiac puncture for hematological and biochemical analyses. Liver, heart, kidney, and spleen were collected for histopathological analysis. Statistical analysis was performed through one-way analysis of variance and only p < 0.05 F-values were presented. Significant reduction in blood glucose in the male group (35%; p < 0.01), transaminases activity in both sexes (AST and ALT; ~35%; p < 0.05), and urea (20%; p < 0.01) in the female group was observed with the lasiodiplodan treatment. The results showed that sub-chronic treatments with lasiodiplodan did not generate hematological and histopathological alterations leading to signs of toxicity in healthy mice, independent of gender.
Overall, these results demonstrated that a single administration of creatine improves working memory efficiency, and, when co-administrated with l-arginine, improves reference memory retention, a phenomenon that is possibly associated with increased creatine/phosphocreatine levels and l-arginine-derived NO synthesis.
Este artigo de revisão bibliográfica se propôs a verificar a possibilidade de associar os conhecimentos neurocientíficos com a Teoria da Aprendizagem Significativa de Ausubel como proposta teórica para facilitar o ensino e aprendizagem de Genética. Os resultados desta revisão mostraram que os conceitos centrais da Teoria da Aprendizagem Significativa (estrutura cognitiva, conhecimentos prévios, aprendizagem mecânica e significativa, mapas conceituais) apresentam um forte correlato neurofisiológico, por isso a interlocução entre Neurociência e Aprendizagem Significativa é possível. Diante disso, conclui-se que a Neurociência associada à Teoria da Aprendizagem Significativa resulta em uma abordagem neurocognitiva, que possibilita uma melhor compreensão dos mecanismos neurais e cognitivos envolvidos no processo de ensino e aprendizagem e, a partir disso, pode oferecer subsídios teóricos e práticos importantes para o trabalho docente, facilitando a aprendizagem significativa de Genética.
PALAVRAS-CHAVE:Neurociência. Aprendizagem significativa. Ensino de genética.
ObjectiveThis study investigated the chronic (oral) and acute (hypothalamic infusion) effects of L-arginine supplementation on feed intake, body composition, and behavioral changes in rats.
MethodsTwenty rats were divided into two groups treated orally for 60 days; one group received L-arginine (1 g/kg body weight) and one group received saline (1 mL/NaCl 0.9%). Daily consumption of water and food were evaluated, and weight monitored. After the oral treatment, the rats underwent stereotactic biopsy and a group was injected with 2 µL of L-arginine (0.5 mM) and another received an injection of saline (0.9% NaCl), in the hypothalamic route, through micro infusion. Immediately after micro infusion, the animal behavior was evaluated through tests in the open field. Food and water consumption were evaluated at 12 and 24 hours after the micro infusion. Daily water consumption and weight gain evolution were evaluated. At the end of treatments, rats were euthanized and blood was collected for glucose, glycerol, and cholesterol evaluation, and histological analysis of vital organs.
ResultsOral supplementation with L-arginine increased water intake (11%, p<0.05) and promoted weight gain (3%, p<0.05). However, hypothalamic infusion promoted a significant increase in chow intake (30%, p<0.05) after 24 hours of L-arginine administration.
Context: Lasiodiplodan, an exocellular (1→6)-β-d-glucan of molecular weight >1.4 × 106 Da produced by MMPI strain of Lasiodiplodia theobromae (Pat.) Griffon & Maubl. (Brotyosphaeriaceae) is known to exhibit anti-proliferative activity on breast cancer cells (MCF-7), anticoagulant activity when sulfonylated, and reduction in transaminase activity when administered in rats.Objective: The effect of intracerebroventricular (I.C.V) injection of lasiodiplodan on neurotoxicity and behavioural changes induced by d-penicillamine was investigated.Materials and methods: Twenty-four male Wistar rats were initially separated in groups of six and treated with 0.15 μmol/μL of NaCl (Groups Ct and d-Pen) and 0.01 μg/μL of lasiodiplodan (Groups Las and Las + d-Pen). After 15 min, they received 6 μmol/μL of NaCl (Groups Ct and Las) and 2 μmol/μL of d-penicillamine (Groups d-Pen and Las + d-Pen). The animal behavior was observed in an open-field test for 60 min. Twenty-four h later, the animals were sacrificed and histopathological analysis and Thiobarbituric acid reactive substances (TBARS) production measurements were performed.Results: Lasiodiplodan prevented neurotoxicity induced by d-penicillamine significantly reducing the production of TBARS (308%; p < 0.05), and behavioural signs; convulsive and pre-convulsive. No histopathological alterations in the cerebral cortex were observed.Discussion and conclusion: The reduction of TBARS production and convulsive episodes suggests that the protector effect provided by lasiodiplodan passes thought an antioxidant path, possibly interfering in a cascade of neurochemical events, triggering cell death and convulsive episodes. These results demonstrated that lasiodiplodan can be effective in treating neurotoxicity, and reducing damage triggered by convulsions in neuropathies related to GABAergic system.
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