Analysis of proteoglycan messages in human articular cartilage by a competitive PCR technique

A competitive PCR technique has been established to allow quantitation of message levels within tissues without the need for cell isolation. The method utilizes an internal RNA standard that uses the same oligonucleotide primers as the authentic message for both reverse transcription and DNA polymerization. While the technique does not give absolute message levels when applied to intact tissues, because of incomplete extraction yields, it can be used to give values relative to any reference message level. The technique has been applied to the analysis of the message levels for aggrecan, versican, link protein, decorin, biglycan, fibromodulin and lumican in human articular cartilage isolated from individuals ranging in age from the neonate to the mature adult. The data indicate that the messages for versican and link protein are always present in lesser abundance than that for aggrecan, and while the aggrecan message levels tend to increase in the adult, those for versican and link protein do not. With respect to the family of leucine-rich repeat proteoglycans, the message for decorin is by far the most abundant at all ages and shows a marked increase in abundance in the adult relative to the juvenile. The messages for fibromodulin and lumican also show increased abundance in the adult, whereas that for biglycan shows no marked age-related trend. The message levels for decorin were also higher than those for aggrecan at all ages.