How does Picrosirius red work?
The special picrosirius red staining highlights the natural birefringence of collagen fibers when exposed to polarized light. The results from birefringence allow to evaluate the organization of the collagen fibers in the tissues.
Does PAS stain collagen?
PAS stains carbohydrates and carbohydrate rich macromolecules a deep red colour (magenta). Mucus in cells and tissues, Basement membranes, and Brush borders of kidney tubules and small and large intestines Reticular fibres (i.e. collagen) in connective tissue and Cartilage.
Does Safranin O stain collagen?
The cationic dye safranin O binds to sulfated glycosaminoglycans and stains them intensely red. The counterstain, fast green, stains collagen green.
What does picrosirius red stain for?
The picrosirius red stain (also called “Sirius red” stain) is one of the best understood histochemical techniques able to selectively highlight collagen networks. Relatively inexpensive, the technique relies on the birefringent properties of collagen molecules.
Is hyaluronic acid PAS positive?
Acid (simple, mesenchymal) – These contain hyaluronic acid and are found in tissue stroma. They do not stain with PAS, but do stain with Alcian blue at pH 2.5, colloidal iron, and metachromatic dyes. They digest with hyaluronic acid.
What is a PAS stain used for?
The periodic acid-Schiff (PAS) staining procedure is most commonly used in the histology laboratory to detect glycogen deposits in the liver when glycogen storage disease is suspected. Glycogen granules may also be visible in tumors of the bladder, kidney, ovary, pancreas, and lung.
What does safranin O do?
General description. Safranin-O, also known as basic red 2, is a biological stain used in histology and cytology. Safranin is used as a counterstain in some staining protocols, colouring all cell nuclei red. It can also be used for the detection of cartilage, mucin and mast cell granules.
Why is safranin a counterstain?
A counterstain, such as the weakly water soluble safranin, is added to the sample, staining it red. Since the safranin is lighter than crystal violet, it does not disrupt the purple coloration in Gram positive cells.
What color is collagen?
Newly formed collagen fibres appear on the 4-6 mum thick sections in green polarization colour. Later, in a more mature stage, they became yellow, orange or red under crossed polaroids.