The microfibril-elastin fiber system distribution in left atrioventricular valve of the rat / Distribución del sistema de microfibrillas y fibras de elastina en la valva atrioventricular izquierda de la rata

The microfibril-elastin fiber system, an important constituent of the extracellular matrix, was studied in the rat left atrioventricular valve to investigate the interrelationship of oxytalan, elaunin and elastic fibers in left atrioventricular valve morphology. The elastin fibers forms continuous bundles observed along the length of the valve in atrial and ventricular layers and oriented parallel to endothelium. The elaunin and oxytalan fibers are distributed in the thickest fiber bundles along the length of the valve. The thinner fibers which radiated towards both the atrial and spongiosa layers, either as isolated or arborescent fiber bundles were identified as oxytalan fibers. With transmission electron microscopy elastic fibers were seen mainly in the atrial layer. The spongiosa layer was composed of elaunin and oxytalan fibers and ventricular layer showed elaunin fibers arranged in continuous bundles parallel to the endothelium. Both fibrillin and elastin were seen and identified by immunocytochemistry with colloidal gold in the left atrioventricular valve spongiosa and atrial layers. These observations allow us to suggest that the microfibril-elastin fiber system plays a role in the mechanical protection and maintenance of the integrity of the rat left atrioventricular valve.

Fue estudiado el sistema de fibras microfibrillas-elastina, un componente importante de la matriz extracelular, en la valva atrioventricular izquierda de rata, con la finalidad de investigar la interrelación de oxitalán, elaunin y fibras elásticas en la morfología de dicha valva. Las fibras de elastina forman paquetes continuos a lo largo de la valva en las capas atriales y ventriculares, orientadas paralelamente al endotelio. Las fibras de elaunin y oxitalán se distribuyen en haces de fibras más gruesas a lo largo de la valva. Las fibras más delgadas, las cuales se irradiaban hacia las capas atrial y esponjosa, ya sea como haces de fibras aisladas o arborescentes, fueron identificadas como fibras oxitalán. En la capa atrial a través de microscopía electrónica de transmisión se observaron principalmente fibras elásticas. La capa esponjosa estaba compuesta por fibras de elaunin y oxitalán; la capa ventricular mostró fibras de elaunin dispuestas en haces continuos paralelos al endotelio. Tanto fibrilina y elastina se observaron e identificaron por inmunocitoquímica con oro coloidal en las capas esponjosa y atrial de la valva atrioventricular izquierda. Estas observaciones nos permiten sugerir que el sistema de fibras de elastina-microfibrillas tienen participación en la protección mecánica y la mantención de la integridad de la valva atrioventricular izquierda en la rata.

Análise biométrica e morfologia do rim de ratos submetidos à restrição proteica gestacional / Biometric analysis and kidney morphologic of rats submitted to gestational protein restriction

Restrição proteica gestacional em ratos está associada ao desenvolvimento de doenças crônicas como diabetes e hipertensão na idade adulta. O objetivo deste estudo foi desenvolver modelo em ratos para o desenvolvimento de hipertensão através da restrição proteica durante a gestação e avaliar a relação da mesma com o baixo peso ao nascer e a morfologia renal. Foram estudados filhotes de ratos, machos e fêmeas, divididos em grupos controle e restrito nas seguintes idades: dia do nascimento, 10 dias, 3 e 6 meses pós-natais. Os animais restritos durante a gestação nasceram com massa corporal e volume renal menor do que os animais que tiveram dieta normoproteica durante a gestação, além de apresentar lesão renal na idade adulta o que provocou desenvolvimento da hipertensão arterial.

Gestational protein restriction in rats is associated with development of chronic diseases like diabetes and hypertension in adulthood. The aim of this study was to develop model in mice to develop hypertension by protein restriction during pregnancy and assess similar relationship with low birth weight and renal morphology. We studied rats, male and female, divided into control group and low protein to the following day of birth, 10 days, 3 and 6 months postnatal. The restricted animals during pregnancy were born with body mass and renal volume smaller than the animals that had normal protein diet during pregnancy, besides having kidney damage in adults what causes the development of hypertension.