Figure 1.

A, Scatterplots demonstrating the relationships between log₂ gene expression levels between normal chondrocytes, intact osteoarthritic (OA) chondrocytes, and fibrillated OA chondrocytes (green and red dots represent genes that exhibit change between groups with P < 0.01). B, Pie charts representing the occurrence of major ontological annotations associated with genes significantly up-regulated and down-regulated in OA chondrocytes, either in location (top) or in process (bottom) categories of the Panther Classification System. Exploded regions on charts emphasize the number of extracellular-associated genes differentially regulated. C, Heatmap representing expression levels of the top 25 up-regulated and the top 25 down-regulated genes in OA chondrocytes. Both the gene and sample lists were subjected to hierarchical clustering. Color key indicates the normalized log₂ hybridization values. Average histologic scores of samples at the bottom are shown in Table1. ECM = extracellular matrix.