Elastase, Rat

Masson’s Trichrome (collagen/trichrome staining) is a histological technique that differentially stains tissue compartments using sequential acidic dyes to distinguish collagen from muscle and cytoplasmic components based on dye affinity and tissue permeability differences, enabling visualization of fibrosis and connective tissue architecture in histological sections. The classical formulation typically uses Weigert's iron hematoxylin for nuclear staining, Biebrich scarlet-acid fuchsin for cytoplasm and muscle, and aniline blue (or light green variants) for collagen, producing a characteristic blue/green collagen signal contrasted against red cytoplasm and dark nuclei. The staining principle relies on selective displacement of smaller dye molecules by larger anionic dyes in collagen-rich regions under controlled acidified conditions, which enhances collagen-specific dye retention. This property makes the method widely used for fibrosis assessment in organs such as heart, liver, lung, a

Elastic fiber staining is a histochemical technique used to selectively visualize elastin-rich structures such as elastic fibers in connective tissues (e. g. , blood vessels, lung, dermis) based on the affinity of specific dyes or oxidation products for elastin-associated amino acid residues and cross-linked elastic matrix components. Classical methods such as Verhoeff-Van Gieson (VVG), resorcin-fuchsin (Weigert-type stains), or aldehyde fuchsin rely on differential binding of dye complexes to elastic fibers, allowing them to be distinguished from collagen and other extracellular matrix components by contrast staining (typically black or deep purple elastic fibers against red collagen counterstain). These methods are widely used in histopathology to evaluate elastic fiber integrity, fragmentation, or remodeling in vascular diseases, pulmonary pathology, and connective tissue disorders.