Desnutrição materna durante a lactação em ratos Wistar: efeitos sobre as fibras elásticas da matriz extracelular na traqueia dos filhotes

Abstract

Objective: To investigate the effects of maternal protein malnutrition during lactation on the elastic fibers in the tracheas of Wistar rat pups. Methods: At delivery, 12 male pups of two Wistar rat dams were equally divided into two groups: control, in which the dam received water and standard rat chow ad libitum during lactation; and protein-restricted (PR), in which the dam received water ad libitum and an isoenergetic PR diet (8% protein). At 21 days of age, the pups were killed and their tracheas were excised. The elastic fibers were stained with Weigert's resorcin-fuchsin (after oxidation) and evaluated under light microscopy. Morphometric determinations were performed by stereology, with the point-counting method, and expressed as volumetric densities. Results: Elastic fibers, most having a longitudinal distribution, were identified beneath the tracheal mucosa. In addition, well-defined circular layers of elastic fibers were found around the inner and outer surfaces of the cartilaginous ring. There were no differences between the groups regarding the organization and distribution of the elastic fibers. The volumetric density of the elastic fibers of the pups in the control and PR groups was 2.46 ± 0.99% and 3.25 ± 1.13%, respectively (p < 0.01). Conclusions: The volumetric density of elastic fibers appears to be greater in rat pups breastfed by dams receiving a PR diet than in those breastfed by dams receiving a normal diet.Keywords: Trachea/growth and development; Trachea/anatomy and histology; Extracellular matrix; Airway remodeling; Malnutrition. ResumoObjetivo: Investigar os efeitos da desnutrição proteica materna durante a lactação sobre as fibras elásticas da traqueia de filhotes de ratos Wistar. Métodos: Ao nascimento, 12 filhotes machos de duas ratas Wistar foram igualmente divididos em dois grupos: grupo controle, cuja mãe recebeu água e dieta padrão de laboratório ad libitum durante a lactação, e grupo restrição proteica (RP), cuja mãe recebeu água ad libitum e dieta isoenergética com RP (8% de proteína). Aos 21 dias de vida, os filhotes foram sacrificados, e suas traqueias foram ressecadas. As fibras elásticas foram coradas pelo método de resorcina-fucsina de Weigert (precedido de oxidação) e avaliadas sob microscopia óptica. As determinações morfométricas foram feitas por estereologia, utilizando o método de contagem de pontos, e expressas em densidade volumétrica. Resultados: As fibras elásticas foram identificadas abaixo da mucosa traqueal, sendo a maioria em distribuição longitudinal. Além disso, camadas circulares bem definidas de fibras elásticas envolviam as superfícies interna e externa do anel cartilaginoso. Não houve diferenças entre os grupos quanto à organização e distribuição das fibras elásticas. A densidade volumétrica das fibras elásticas dos filhotes nos grupos controle e RP foi de, respectivamente, 2,46 ± 0,99% e 3,25 ± 1,13% (p < 0,01). Conclusões: Nossos resultados sugerem que a densidade volumétrica de fibras elásticas é maior em filhotes de ratos alimentados por fê...

Publicações do Jornal Brasileiro de Pneumologia

“…There were three studies involving ex vivo experimental models. ( 13 - 15 ) The use of a surgical adhesive for lung repair after lobectomy was tested in rats, ( 16 ) the extracellular matrix of the rat trachea was examined, ( 17 ) an experimental rat model of pulmonary hypertension ( 18 ) was studied, and the use of a self-expanding tracheal stent was tested in rabbits. ( 19 ) Murine models of allergic response ( 20 ) and of protective ventilation strategies ( 21 ) were studied.…”