Gomori’s Silver Impregnation Staining Technique for Reticulin Fibers

Reticular fibre is the type of connective tissue composed of type III collagen secreted by reticular cells.

Principle

Gomorri’s technique involves the impregnation of silver for the demonstration of reticular fibres. Since the reticular fibres have low affinity for silver salts, a suitable pretreatment in order to enhance the selectivity to impregnation is required. Treatment with silver solution has two fold effects :

1. Creation of submicroscopic sensitized sites of silver introduced in reticular fibres.
2. Uptake of considerable amounts of silver by tissues in reduced form.

On treatment with reducing agent, silver taken up by tissues is converted into metallic silver which is deposited and appears dark brown or black deposits on sensitized sites. For permanent preparation, gold chloride is used.

Requirements

1. 0.5% Potassium permanganate (KMnO4)
2. 0.5% Oxalic acid
3. 4% Ferric chloride (FeCl3)
4. 0.2% Auric chloride
5. 20% Formalin
6. 5% Sodium thiosulphate
7. Silver solution (Ammonical silver nitrate)

10% silver nitrate = 10ml
40% Sodium hydroxide = 1-2 drops
The solution will become turbid. Add ammonia drop by drop with constant shaking untill the turbidity dissappears. Make final volume 40ml by adding distilled water.

Procedure

1. Deparaffinize and bring sections to distilled water.
   (Zenker fixed tissues are commonly used. Tissue sections should be taken through an iodine-sodium thiosulphate sequence)
2. Oxidize with 0.5% KMnO4 for 2 minutes.
3. Wash in tap water.
4. Bleach with 0.5% oxalic acid solution to colorless stage for 1-2 minutes.
5. Wash in tap water.
6. Treat with 4% Ferric chloride for 2 minutes.
7. Wash in running tap water for 3 minutes.
8. wash thoroughly in distilled water.
9. Place slides in couplin jar containing ammonical silver nitrate solution for 1-5 minutes.
10. Rinse in distilled water for 20 seconds.
11. Treat with 20% formalin for 1-3 minutes.
12. Wash in tap water for 3 minutes.
13. Treat with 0.2% Gold chloride solution for 10 minutes.
14. Rinse in distilled water.
15. Treat with 0.5% sodium thiosulphate for 1-5 minutes.
16. Rinse in distilled water.
17. Counterstain as desired (Van Gienson or Eosin is suitable).
18. Dehydrate through increasing concentration of alcohol.
19. Clear in xylene and mount to permanent mounting medium.

Result and Interpretation

Reticular fibres : Black or dark brown

Nucleas : Grey

Other tissues : According to counterstain