Microarray analysis of differential gene expression in temporomandibular joint condylar cartilage after experimentally induced osteoarthritis.

OBJECTIVE

To identify the gene expression profile of mandibular condylar cartilage after experimentally induced osteoarthritis (OA).

DESIGN

We studied the gene expression levels in temporomandibular joint (TMJ) condylar cartilage during different stages of experimentally induced OA. The pathological characteristics of normal, early-stage and late-stage osteoarthritic TMJ cartilage were verified by histological techniques. The gene expression profiles in normal and osteoarthritic cartilage were measured by Affymetrix RAE230A microarrays. Some of the gene transcripts were confirmed by quantitative real-time reverse-transcription PCR analysis.

RESULTS

A comprehensive, differentially expressed, gene profile was obtained in TMJ cartilage during the progression of OA. In total, 138 genes and expressed sequence tags were up- or down-regulated at least 2-fold. Some of these genes have been shown to play a role in OA, including matrix-degrading proteases, protease inhibitors and genes involved in cell growth, apoptosis and bone remodeling. However, some genes that had never been reported to be related with OA, such as AQP3, SPP2, NOV, DKK3 and EGLN3, were consistently observed to be up-regulated in this study, suggesting they may be involved in OA progression.

CONCLUSION

This study provides a new gene expression profile of the progression of OA. Further study of these OA-related genes may provide new insights into understanding the molecular mechanisms underlying OA.