摘要

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 interrelaci車n de oxital芍n, elaunin y fibras el芍sticas en la morfolog赤a 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 oxital芍n se distribuyen en haces de fibras m芍s gruesas a lo largo de la valva. Las fibras m芍s delgadas, las cuales se irradiaban hacia las capas atrial y esponjosa, ya sea como haces de fibras aisladas o arborescentes, fueron identificadas como fibras oxital芍n. En la capa atrial a trav谷s de microscop赤a electr車nica de transmisi車n se observaron principalmente fibras el芍sticas. La capa esponjosa estaba compuesta por fibras de elaunin y oxital芍n; la capa ventricular mostr車 fibras de elaunin dispuestas en haces continuos paralelos al endotelio. Tanto fibrilina y elastina se observaron e identificaron por inmunocitoqu赤mica 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 participaci車n en la protec

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