Description:
Weil’s stain is a modification for paraffin sections of the Weigert-Pal-Kulschitsky technique. The underlying principle of these methods involves the reduction of chrome salt to chromium dioxide by myelin. The chromium subsequently acts as a mordant for the haematoxylin,
intensifying the stain.
Procedure:
This procedure is generally conducted on sections from formalin-fixed, paraffin-embedded tissue that are cut between 8-15 µm. Spinal cord tissue is rich in myelinated axons and can be used as a positive control.
1. Dewax and hydrate sections to distilled water.
2. Put slides in freshly prepared Staining Solution at 56-60C for 30 minutes.
3. Wash slides well in water.
4. Partially differentiate in iron alum differentiating solution until myelin sheaths stand out blueish-black on a pale grey background, approximately 5 minutes. If you are unsure, check your sections under the microscope at1 minute intervals).
5. Wash slides in tap water for 10 minutes.
6. Complete differentiation in Weigert’s differentiator, 1 to 2 minutes. Control this differentiation step carefully checking under the microscope, until the myelin is an intense deep blue against a creamy or clear background.
7. Wash well in tap water.
8. Dehydrate through a series of graded ethanol baths, clear in xylene, and mount.