Abstract
Introduction and Aims: Aberrations in the balance of chondrocyte metabolism play an integral role in the degeneration of articular cartilage and subsequent osteoarthritis. Gene expression profiling allows a comparison of levels of mRNA expression in large numbers of genes simultaneously. This study compares the mRNA expression from osteoarthritic cartilage in knees and hips with that of normal cartilage.
Method: Human cartilage samples were obtained from osteoarthritic knees and hips at the time of joint arthroplasty surgery. ‘Normal’ cartilage was obtained from femoral heads after fracture or from radial heads after trauma. Cartilage samples were either snap frozen in liquid nitrogen or enzymatically digested and established in primary cell culture prior to RNA isolation. The RNA was reverse-transcribed to cDNA, labelled with a fluorochrome and then hybridised to gene chips.
Results: In addition to confirming that cells raised in primary cell culture dedifferentiate to a fibroblast-like state and cease to synthesise normal products of cartilage matrix we have also developed a reproducible method of processing snap frozen cartilage samples in order to produce a sufficiently pure quantity of mRNA to be used in gene chip technology. We now have gene chips completed for a ‘normal’ control, a standard osteo-arthritic knee and an osteoarthritic hip with a significant genetic history of early onset osteoarthritis. Early analysis and comparison of the data from these chips identifies some potential candidate genes for further analysis.
Conclusion: Human articular cartilage lends itself to gene profiling using cDNA arrays as it contains only one cell type. Thus any changes in gene expression levels can be directly attributable to the chondrocyte. This early data analysis opens the door to a new search for the ‘arthritis gene’. For the data to be meaningful we will need to process gene chips on several more samples of arthritic and ‘normal’ cartilage.
These abstracts were prepared by Editorial Secretary, George Sikorski. Correspondence should be addressed to Australian Orthopaedic Association, Ground Floor, The William Bland Centre, 229 Macquarie Street, Sydney, NSW 2000, Australia.
At least one of the authors is receiving or has received material benefits or support from a commercial source.
