Luxol fast blue (LFB) stain is used to identify myelin in nervous tissue. This staining technique takes advantage of a simple acid-base reaction. LFB is a sulfonated copper phthalocyanine dye. Tissue sections are stained with the LFB staining solution to allow the base of the dye to exchange with the base of the myelin proteolipid, resulting in a dark blue precipitate. The excess dye is removed with 95% ethanol, then the tissue section is differentiated in lithium carbonate and 70% ethanol until the gray matter is colorless. The white matter will be blue to blue-green.
Cresyl violet is used to stain for neuronal cell bodies and processes. Nissl substance has a high ribonucleic acid (RNA) content, making it very basophilic. Cresyl violet is a basic aniline dye used to selectively stain Nissl by immersing tissue sections in the staining solution and then differentiating in alcohol until the background is colorless.
