Collagen is classified into a number of structurally and genetically distinct types. We use the nomenclature proposed by Bornstein and Traub. Do not confuse Sigma type designations with recognized collagen classification types.

Collagen protein is abundantly present in human. It is the prime structural constituent of dermis. It is also an important constituent of extracellular matrix (ECM).

Collagen from bovine tracheal cartilage has been used to induce arthritis in male DBA/1 mice. It has also been used as a fluorophore to acquire fluorescence emission spectra on the reflectance and fluorescence lifetime spectrometer (RFLS).

Collagen-type II has been investigated for its importance in haemostasis. Two peptides, CB8 and CB11, are sites of platelet binding and activation on collagen-type II. Collagen-type II has also been used as a model for arthritis in animals, where FR140423, a selective cyclooxygenase (COX)-2 inhibitor, has shown an anti-inflammatory effect without gastric lesions that may occur with treatment via indomethacin.

Collagen Type II is sometimes used to induce an animal model of rheumatoid arthritis. However, under conditions leading to formation of reactive oxygen species, the subjects develop tolerance for auto-antibodies. This is an unusual situation of ROS having a favorable effect.

Collagen participates in the aging process. It offers a structural framework for cells and mechanical strength to tissues.

Prepared by a modification of the pepsin extraction procedure of Trentham, et al., J. Exp. Med., 146, 857 (1977).