A modified method for the selective staining of elastic system fibers in methacrylate tissue sections

RESUMO

The elastic system fibers are abundant elements of the extracellular matrix found in organs such as skin, blood vessels, lung and in elastic cartilage and elastic tendons. These fibers have been studied by several selective staining methods, such as resorcin-fuchsin for light microscopy and hematoxylin-eosin plus fluorescence and confocal scanning laser microscopy. However, most of these techniques are only efficient for tissues embedded in paraffin or paraplast, since most dyes show low penetration into glycol methacrylate resins. In this report, we describe a variation of Weigert´s resorcin-fuchsin method that involves the pretreatment of resin sections with potassium permanganate. This procedure increased the affinity between the dye and elastic fibers, and stained the elastic fibers in black of dark violet, the nuclei in purple and other structures in light blue. Thus, this modification of the original method provided excellent artifact-free demarcation of elastic fibers in well-preserved tissues.