Collagen Fiber (Collagen Fiber) is the most widely distributed connective tissue in the most content of a fiber, widely distributed in a variety of organs, including the skin, sclera, tendons are the most abundant, type I collagen fibers are mainly bone, skin, tendon fibers; type II collagen fibers are mainly cartilage collagen; type III collagen fibers are mainly in the embryonic tissues, adult blood vessels, gastrointestinal tract; type IV collagen fibers are mainly in the basement membrane in the basement membrane. Sirius Red and its lining dye solution are both strong acidic dyes, easy to combine with the alkaline groups in the collagen molecule, adsorbed firmly, polarized light microscopy, collagen fibers have positive uniaxial birefringent light properties, and the combination of Sirius Red Composite Staining Solution enhances the birefringence and improves the resolution, thus distinguishing between the two types of collagen fibers.

Sirius Red Staining Solution Set consists of Hematoxylin Staining Solution and Sirius Red Staining Solution, which is mainly used for the study of collagen fiber abnormality or fibroplasia in various tissue lesions. The collagen fibers of the cardiac blood vessels and other tissues are stained red under the general optical microscope, and it is helpful for the study of the typing and classification of various fibrotic lesions under the polarized light microscope, and the use of immunohistochemical technology can also show the collagen fibers of type Ⅰ and Ⅲ, but the antibodies used are expensive. The immunohistochemical technique can also show type I and type III collagen fibers, but the antibody used is expensive and time-consuming to operate, while the Sirius red staining reagent is cheap and simple to operate.