Collagen is the main structural protein component of extracellular matrix of the connective tissue in humans, making upto 25% to 35% of the whole-body protein content. Collagen arranged in elongated fibrils is found in fibrous tissues like tendons, ligament, skin as well as in bones, cartilage, muscle and dental tissues. Depending upon the degree of mineralization, collagen tissues could be rigid (bone), compliant (tendon) or in between rigid to compliant (cartilage). The fibroblast is the most common cell that is responsible for the formation of collagen. The biosynthesis of collagens starting with gene transcription of the genes within the nucleus to the aggregation of collagen heterotrimers into large fibrils is a complex multistep process. Degradation of collagen takes placeintracellularly and extracellularly. Microscopically, collagen is demonstrated by various histochemical stains. It has a triple helical structure, composed of three interwined polypeptide chains. It is important to health as it forms the major component of many vital tissues in body and is essential in maintenance of structure and function of body.
