The mandible condylar process cartilage (CP) of Wistar rats is a secondary cartilage and acts as a mandibular growth site. This phenomenon depends on adequate proteins intake and hormone actions, including insulin.ObjectivesThe present study evaluated the morphological aspects and the expression of the insulin receptor (IR) in the cartilage of the condylar process (CP) of rats subjected to protein undernourishment.Material and MethodsThe nourished group received a 20% casein diet, while the undernourished group (U) received a 5% casein diet. The re-nourished groups, R and RR, were used to assess the effects of re-nutrition during puberty and adulthood, respectively. CPs were processed and stained with picro-sirius red, safranin-O and azocarmine. Scanning electron microscopy and immunohistochemistry were also performed.ResultsThe area of the CP cartilage and the number of cells in the chondroblastic layer decreased in the U group, as did the thickness of the CP layer in the joint and hypertrophic layer. Renourishment during the pubertal stage, but not during the adult phase, restored these parameters. The cell number was restored when re-nutrition occurred in the pubertal stage, but not in the adult phase. The extracellular matrix also decreased in the U group, but was restored by re-nutrition during the pubertal stage and further increased in the adult phase. IR expression was observed in all CPs, being higher in the chondroblastic and hypertrophic cartilage layers. The lowest expression was found in the U and RR groups.ConclusionsProtein malnutrition altered the cellularity, the area, and the fibrous cartilage complex, as well as the expression of the IRs.

OBJETIVO: A lesão térmica conduz o organismo a processos catabólicos a fim de reparar a área lesada. O propósito do presente estudo foi avaliar os efeitos da lesão térmica por escaldadura na morfologia das fibras musculares de um músculo distante da lesão. MÉTODOS: Foram utilizados 30 ratos Wistar, divididos em: Grupo submetido à lesão térmica por escaldadura (S) e Grupo Controle (C). A escaldadura foi provocada em 45% da superfície corporal dos animais e padronizada pelo peso corpóreo. A eutanásia ocorreu nos períodos pós-lesão de quatro, sete e 14 dias. Retirou-se a parte média dos músculos gastrocnêmio medial os quais foram submetidos à técnica histológica de Hematoxilina-Eosina e Picrosírius. RESULTADOS: O aspecto poligonal das fibras musculares, com núcleos periféricos, bem como a distribuição eqüidistante das mesmas, característico das descrições da musculatura normal, verificado nos animais do grupo C não foi uma constante nas fibras do músculo dos animais do grupo S. Nestes, muitas fibras exibiram contorno arredondado, diferentes intensidades de marcação bem como maior distanciamento entre as mesmas. Observou-se ainda aumento substancial da quantidade de tecido conjuntivo no grupo S. CONCLUSÃO: Houve alteração da morfologia do músculo distante da lesão como resposta à lesão térmica de 45% em modelo experimental.

PURPOSE: Thermal injury causes catabolic processes as the body attempts to repair the damaged area. This study evaluated the effects of a scald injury on the morphology of muscle fibers belonging to a muscle distant from the lesion. METHODS: Thirty Wistar rats were divided into control (C) and scalded (S) groups. Group S was scalded over 45% of the body surface, standardized by body weight. Rats in both groups were euthanized at four, seven and 14 days following the injury. The middle portions of the medial gastrocnemius muscles were sectioned, stained with hematoxylin and eosin and Picrosirius, and submitted to histological analysis. RESULTS: Control group sections exhibited equidistantly distributed polygonal muscle fibers with peripheral nuclei, characteristic of normal muscle. The injured group sections did not consistently show these characteristics; many fibers in these sections exhibited a rounded contour, variable stain intensities, and greater interfiber distances. A substantially increased amount of connective tissue was also observed on the injured group sections. CONCLUSION: This experimental model found a morphological change in muscle distant from the site of thermal injury covering 45% of the body surface.