Van Gieson's stain

Van Gieson's Stain is a mixture of Picric Acid and Acid Fuchsin. It is the simplest method of differential staining of Collagen and other Connective Tissue.

Formula The solution weakens after long standing and may be strengthened by adding few drops of fresh Acid Fuchsin.
 * 100 mL of Saturated Aqueous solution of Picric Acid added to 5 mL of 1% Aqueous solution of Acid Fuchsin.

Staining Connective Tissue with Van Gieson's
Recommended Fixative
 * Mercuric Chloride fixative, although Formol-Saline also gives good results.

Procedure
 * 1) Tissue sections to Ethyl Alcohol
 * 2) Stain with Weigert's Iron Hematoxylin for 15 minutes
 * 3) Wash in running water for 15 minutes
 * 4) Rinse with distilled water
 * 5) Place in Van Gieson's stain for 5 minutes
 * 6) Rinse in distilled water
 * 7) Rinse rapidly in 70% Ethyl Alcohol
 * 8) Dehydrate rapidly in Absolute Alcohol, clear and mount in Neutral Balsam. Acid medium, if used for mounting will make stains fade rapidly.

Results
 * Nuclei - stains brownish black to black
 * Collagen (Fibrous Connective Tissue) - stains pink or deep red
 * Muscle, Cytoplasm, RBC and Fibrin - stains yellow

Note:
 * 1) If the duration of staining is strictly followed, there is no need to differentiate in 1% Acid Alcohol. The tissue sections are instead, differentiated by Picric Acid in the Van Gieson's Stain.
 * 2) Differentiation of Collagen and smooth muscles may be accomplished in steps 6 and 7. Van Gieson's Stain consists of Acid Fuchsin, which is readily soluble in alcohol, and Picric acid, which is readily soluble in water. Washing appropriately with solvent will accentuate one and remove the other.
 * 3) Nuclei stained with Alum Hematoxylin is readily decolorized by Picric Acid; Iron Hematoxylin may also be used.
 * 4) Young fibrils do not take the deep red stain imparted to mature collagen. RBC tends to fade after sometime.

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Reference

 * Jocelyn H. Bruce-Gregorios, M.D.: Histopathologic Techniques, JMC Press Inc., Quezon City, Philippines, 1974. ISBN: 971-11-0853-4