Cartilage stain solution (toluidine blue method)

Cartilage tissue is composed of chondrocytes, cartilage matrix and fibers. Cartilage tissue and its surrounding perichondrium constitute cartilage. Cartilage is divided into hyaline cartilage, elastic cartilage and fibrous cartilage according to the different cellulose components contained in the matrix. There are many methods for cartilage staining, such as toluidine blue method, alcian blue method, Safranin O method, etc.

Toluidine Blue is a commonly used synthetic dye, belonging to the quinoneimine dye class. This type of dye mainly contains two chromophores, an amine group and a quinone-type benzene ring, so that the chromogen develops color. The cations in toluidine blue have a dyeing effect, and the acidic substances in tissue cells combine with the cations to be dyed. Toluidine blue contains not only two chromophores, but also two auxochromophores, which can promote the ionization of the dye into salts, help the chromophores to produce staining power on the tissue, color the tissue cells on the slice, and can dye the cell nucleus to make it blue; the mast cell cytoplasm contains heterochromatic substances such as heparin and histamine, which can show metachromatic purple-red when encountering toluidine blue.

The cartilage stain solution (toluidine blue method) is strongly alkaline, which is more conducive to the coloring of tissue cells.