Thionin Staining Thionin Staining For the histology part of the lab, you will section fixed formaldehyde fixed rat brain tissue using a cryostat, and then use a Nissl stain, called Thionin stain, which will stain the Nissl substance bright blue. Rat brains have already been fixed.
Fixation preserves the tissue and holds it together.
If the tissue is not fixed, and is run through the staining procedure, it will disintegrate before the staining procedure is completed. Subbing involves dissolving the gelatin in warm water, dipping the slides into it, then letting them dry. Sectioning will be performed on a cryostat. A print brush can be used to move your section, as well as to clean the blade. Brains will be affixed to a small holder with a liquid called Histo Prep.