Refinement as ethics principle in animal research: Is it necessary to standardize the Environmental enrichment in laboratory animals?

The Environmental enrichment technique, although scientifically recognized for raising the level of animal welfare, has led to the questioning of its influence on the results of experimental research. Thus, the goal is to promote reflection about the need for standardization of these procedures. For that, documents and experimental analysis were done, in order to quantify and characterize the types of environmental enrichment used and to evaluate the effect of that in the social behavior of Rattus norvegicus. Data from the document review confirmed the hypothesis that the researchers have used a variety of methods, not demonstrating a concern for standardization and prior assessment of its effects on the search results. Demand was corroborated in the experimental study in which, although there was available a simple object acting as refuge promotes behavioral improvements, the presence of the co-specific, as well as characteristics of the micro and macro environment can compromise the homogeneity of the sample. The data from this study endorse the need for validation procedures of environmental enrichment for specific proposals, to investigative data comparison, are possible and contribute to the refinement of the search to reduce the number of animals targeted for this purpose.

Hierarchical Virtual Screening of Potential New Antibiotics from Polyoxygenated Dibenzofurans against Staphylococcus aureus Strains.

Staphylococcus aureus is a microorganism with high morbidity and mortality due to antibiotic-resistant strains, making the search for new therapeutic options urgent. In this context, computational drug design can facilitate the drug discovery process, optimizing time and resources. In this work, computational methods involving ligand- and structure-based virtual screening were employed to identify potential antibacterial agents against the S. aureus MRSA and VRSA strains. To achieve this goal, tetrahydroxybenzofuran, a promising antibacterial agent according to in vitro tests described in the literature, was adopted as the pivotal molecule and derivative molecules were considered to generate a pharmacophore model, which was used to perform virtual screening on the Pharmit platform. Through this result, twenty-four molecules were selected from the MolPort® database. Using the Tanimoto Index on the BindingDB web server, it was possible to select eighteen molecules with greater structural similarity in relation to commercial antibiotics (methicillin and oxacillin). Predictions of toxicological and pharmacokinetic properties (ADME/Tox) using the eighteen most similar molecules, showed that only three exhibited desired properties (LB255, LB320 and LB415). In the molecular docking study, the promising molecules LB255, LB320 and LB415 showed significant values in both molecular targets. LB320 presented better binding affinity to MRSA (-8.18 kcal/mol) and VRSA (-8.01 kcal/mol) targets. Through PASS web server, the three molecules, specially LB320, showed potential for antibacterial activity. Synthetic accessibility (SA) analysis performed on AMBIT and SwissADME web servers showed that LB255 and LB415 can be considered difficult to synthesize and LB320 is considered easy. In conclusion, the results suggest that these ligands, particularly LB320, may bind strongly to the studied targets and may have appropriate ADME/Tox properties in experimental studies.

Nitric oxide synthesis is increased in cybrid cells with m.3243A>G mutation.

Nitric oxide (NO) is a free radical and a signaling molecule in several pathways, produced by nitric oxide synthase (NOS) from the conversion of L-arginine to citrulline. Supplementation of L-arginine has been used to treat MELAS (mitochondrial encephalopathy with lactic acidosis and stroke like syndrome), a mitochondrial disease caused by the m.3243A>G mutation. Low levels of serum arginine and endothelium dysfunction have been reported in MELAS and this treatment may increase NO in endothelial cells and promote vasodilation, decreasing cerebral ischemia and strokes. Although clinical benefits have been reported, little is known about NO synthesis in MELAS. In this study we found that osteosarcoma derived cybrid cells with high levels of m.3243A>G had increased nitrite, an NO metabolite, and increased intracellular NO, demonstrated by an NO fluorescent probe (DAF-FM). Muscle vessels from patients with the same mutation had increased staining in NADPH diaphorase, suggestive of increased NOS. These results indicate increased production of NO in cells harboring the m.3243A>G, however no nitrated protein was detected by Western blotting. Further studies are necessary to clarify the exact mechanisms of L-arginine effect to determine the appropriate clinical use of this drug therapy.

Artérias da base do encéfalo em suínos da linhagem Camborough 22 / Arteries of the base of the encephalon in pigs from the lineage Camborough 22

As artérias da base do encéfalo foram estudadas em 40 suínos da linhagem Camborough 22, natimortos, de ambos os sexos. Destes, dez espécimes tiveram as artérias da cabeça preenchidas com solução corada de Acetato de vinyl, e por conseguinte submetidos ao processo de corrosão em solução aquosa, a 25 por cento, de Ácido sulfúrico. Em outros 30 animais, injetou-se solução aquosa, a 50 por cento, de Neoprene Látex 450 corada com pigmento específico e daí fixados em solução aquosa, a 10 por cento, de formaldeído. As artérias da base do encéfalo estiveram na dependência das redes admiráveis epidurais rostral e caudal. A artéria carótida do encéfalo após sua emergência na rede admirável epidural rostral forneceu os ramos rostral e caudal. A rede admirável caudal e ainda a artéria espinhal ventral foram responsáveis pela formação da artéria basilar, que se estendeu caudorostralmente diminuindo o seu calibre até anastomosar-se através de seus ramos terminais com os ramos caudais das artérias carótidas do encéfalo. O circuito arterial do encéfalo teve seu arranjo caracterizado a partir dos ramos rostrais e caudais das artérias carótidas do encéfalo e também dos ramos terminais da artéria basilar.