Resorcinfuchsin

Resorcinfuchsin, commonly referred to as Weigert's resorcin-fuchsin, is a histological stain used to visualize elastic fibers in tissue sections. The method employs a solution containing resorcinol and basic fuchsin that binds selectively to elastin, yielding a dark purple to black coloration of elastic fibers. In many protocols, a counterstain such as Van Gieson or picro-Sirius red is used to differentiate other connective tissue components; collagen fibers take on pink to red or yellow hues depending on the counterstain.

Procedure basics: After fixation, paraffin sections are deparaffinized and hydrated, then stained with the resorcin-fuchsin solution. Differentiation in acidified solution is often used to reduce non-elastic staining. The slide is then counterstained and mounted for microscopic examination.

Applications: It is widely used in histology and pathology to assess the integrity of elastic networks in arterial walls, bronchial and alveolar walls in the lung, dermal elastic fibers, and other elastin-rich structures. It assists in diagnosing conditions involving elastic fiber disruption, such as arteriosclerosis, cutaneous elastosis, and certain congenital connective tissue disorders.

Variants and related stains: Weigert's resorcin-fuchsin is the principal variant; it is sometimes used interchangeably with other elastic stains, though these methods differ in reagents and color outcomes.

Notes: The technique requires careful timing and pH control; staining intensity can vary with preparation, and modern elastin stains offer alternative options. Safety considerations apply due to handling of phenolic dyes and solvents.