McFarlane's Trichrome
1st Variant for Muscle and Collagen

Solutions

Weigert's iron hematoxylin or equivalent
Solution A
Picric acid 0.2 g
Acid fuchsin 1 g
Aniline blue 2 g
Phosphotungstic acid 1 g
Acetic acid, glacial 2 mL
Distilled water 98 mL
Solution B
Acetic acid, glacial 2 mL
Distilled water 100 mL
Solution C
Picric acid 0.25 g
Phosphotungstic acid 2.5 g
Ethanol, 95% 10 mL
Distilled water 90 mL

Tissue sample
5µ paraffin sections of neutral buffered formalin fixed tissue are suitable. Other fixatives are likely to be satisfactory. Most trichrome stains benefit from picric acid or mercuric chloride fixation. Formalin fixed tissues may benefit from secondary fixation of sections in Bouin's fluid.

Method

  1. Bring sections to water via xylene and ethanol.
  2. Stain nuclei with Weigert's iron hematoxylin or equivalent.
  3. Place into solution A for 5 minute.
  4. Rinse with solution B.
  5. Rinse with distilled water.
  6. Place into solution C until differentiated.
  7. Rinse with distilled water.
  8. Wash with solution B.
  9. Dehydrate with ethanol.
  10. Clear with xylene and mount with a resinous medium.

Expected results

Notes

  1. McFarlane also published two other, multi-step, trichrome methods. One is simpler than the other.
  2. Solutions A and C require dry weights of picric acid. This could be provided from a saturated aqueous solution (1 g in 78 mL). Alternate formulas are:–
     
    Solution A         Solution C
    Picric acid, sat. aqueous 16 mL Picric acid, sat. aqueous 20 mL
    Distilled water 82 mL Distilled water 70 mL
    Acetic acid, glacial 2 mL Ethanol, 95% 10 mL
    Acid fuchsin 1 g Phosphotungstic acid 2.5 g
    Aniline blue 2 g
    Phosphotungstic acid 1 g

 

Reference
Gray, Peter. (1954)
The Microtomist's Formulary and Guide.
Originally published by:– The Blakiston Co.
Republished by:– Robert E. Krieger Publishing Co.
  Citing:–
    McFarlane, (1944)
    Stain Technology, v. 19, pp. 29

 


 

 

Translate in
Google Translate
Instructions