Efeitos da biomembrana de látex natural (Hevea brasiliensis) em pele de ratos Wistar submetidos à lesão térmica corporal por escaldamento / Effects of the natural latex biomembrane(Hevea brasiliensis) in Wistar rat skin submitted to body thermal injury by scalding

Objetivo: As implicações cosméticas para o tratamento de queimaduras têm levado à busca de estratégias farmacêuticas que otimizem em tempo e qualidade o processo de reparação do tecido comprometido. Nesse sentido, a proposta deste estudo foi investigar os efeitos da biomembrana de látex natural (Hevea brasiliensis) em pele de ratos com lesão térmica por escaldamento. Método: No total,18 ratos Wistar foram divididos em três grupos (GI, controle; GII, com lesão térmica sem tratamento; e GIII, tratado com biomembrana de látex natural). Os animais foram eutanasiados no período de 4 e 14 dias pós-lesão. Amostras coletadas do tegumento dorsal de todos os animais foram analisadas por microscopia de luz e eletrônica de varredura, histomorfometria e estereologia para quantificação da densidade de volume das fibras elásticas, do tecido de granulação e do colágeno ali presente. Resultados: Os resultados macro e microscópicos demonstraram que o grupo III apresentou melhor cicatrização comparada ao grupo GII. Foi observado que as fibras colágenas e elásticas, embora estivessem com densidade de volume menor no grupo III, apresentaram-se em uma rede organizada, assim como notou-sea incidência de folículos pilosos, novos vasos sanguíneos e aumento do tecido de granulação. Conclusão: Os dados permitiram concluir que a biomembrana de látex natural favoreceu a cicatrização em áreas queimadas e a neoangiogênese, sugerindo que o biomaterial utilizado é um recurso terapêutico promissor para a cicatrização da pele.

Purpose: The cosmetic implications for burn treatment, has led to the search of pharmaceutical strategies that optimize in time and quality the repair process of the affected tissue. Due this fact, the purpose of this study was to investigate the effects of natural latex biomembrane (Hevea brasiliensis) in the skin of rats with body thermal injury by scalding. Method: Totally, 18 Wistar rats were allocated into three groups (GI, control; GII, scalded without treatment; and GIII, treated with natural latex biomembrane). Individuals were euthanized at 4 and 14 days post-burn. Then, samples of the dorsal region of all animals were assessed by means of light and scanning electron microscopy, histomorphometry and stereology to quantify the volume density of elastic fibers, granulation tissue and collagen fibers inside it. Results: According to the gross and microscopic results, the group III showed better healing compared to GII. Although the collagen and elastic fibers had lower volume density in the group III, they were organized in a network of fibers. In addition, were observed hair follicles, blood vessels, and increase of granulation tissue. Conclusion: According to the results, the natural latex biomembrane helped the healing and neoangiogenesis in burned areas, suggesting that the biomaterial is a promising therapeutic tool for healing the skin. KEYWORDS: Skin. B

Three-dimensional aspects of the structural characteristics and kidney angioarchitecture of adult and aged Wistar rats: a scanning electron microscopy study.

The aim of this study was to describe the structural morphological characteristics and organization of the kidney angioarchitecture in adult and aged Wistar rats using different scanning electron microscopy (SEM) methods. Twenty male Wistar rats (Rattus norvegicus) were divided into two groups: the Adult Group (n = 10), which included animals at 3 months of age, and the Aged Group (n = 10), which included animals at 24 months of age. Kidney samples from both groups were analyzed using three distinct SEM methods: coronal sections, cryofracturing and vascular corrosion casts/angioarchitecture. This study demonstrates the specificity of each technique for three-dimensional morphological analyses of the kidney using SEM. In the coronal sections, it was possible to view the structures on a given plane; the stratigraphy was best observed in the cryofracture method, and the vascular corrosion casts showed the organization and arrangement of the angioarchitecture. Thus, we concluded that the SEM methods together provide the best description of the morphological characteristics of normal and pathological kidneys of adult and aged Wistar rats.

Histochemical and ultrastructural changes of sternomastoid muscle in aged Wistar rats.

The aim of this study was to evaluate histochemically and ultrastructurally the sternomastoid muscle (SM) of adults and aged rats, employing histochemic (NADH-TR reaction) and transmission electron microscopic methods. It was used 20 rats, divided into two groups: adults (n=10), animals with 4 months of age, and aged group (n=10), animals with 24 months of age. Five animals from each group were anesthetized with an overdose of urethane (3g/kg i.p.), and the muscles dissected after the samples processing for histochemical reaction (NADH-TR). Three types of fibers were identified by their metabolic characteristics: fibers with high oxidative capacity (O), intermediate oxidative capacity (OG) and low oxidative capacity (G). For transmission electron microscopic method, the animals were anesthetized and perfused by modified Karnovsky solution and the tissues were postfixed in 1% osmium tetroxide solution, dehydrated and embedded in Spurr resin. It was performed ultra-thin sections for transmission electron microscopic analysis. The SM showed heterogeneity in their composition according to the fiber types, with significant difference (p<0.05) when comparing the fibers types between the superficial and deep regions and between the adult and aged groups. It was observe a decrease between the comparison of the total fibers density and GO fiber, and an increase of the O fiber in aged group. Ultrastructural characteristics of muscle cells in aged group showed typical morphological changes, characterizing muscular atrophy. We conclude based on physiological ageing process, changes in muscle fibers classification, and ultrastructuraly, morphological alterations on muscle cells, characterizing a muscular atrophy.