ELEVATED AGGRECAN MESSENGER-RNA IN EARLY MURINE OSTEOARTHRITIS

Male STR/ort mice develop osteoarthritis in the tibial articular carti lage. Low grade histological lesions first appear between 10-20 weeks of age. A previous study showed that the level of aggrecan, the major cartilage proteoglycan, is approximately twofold greater in the tibial cartilage of 16-19-week-old STR/ort mice compared with that in normal cartilage in control CBA mice. In the present investigation aggrecan gene transcription was investigated in 20-week-old STR/ort and CBA. ti bial cartilage using a quantitative reverse transcription-polymerase c hain reaction (RT-PCR). The amount of aggrecan cDNA obtained from the STR/ort medial and lateral plateau was 2.8- and 4.6-fold greater per m illigram of wet cartilage than that from the CBA tibial plateau. The d ifference was not due to differences in cellularity of tibial cartilag e in the two strains and indicates that aggrecan gene transcription is elevated in early osteoarthritis.