Figure 1

Gene expression of MMPs, aggrecan, and type II collagen. Quantification of gene expression of (a) MMP-3, (b) MMP-1, (c) aggrecan, and (d) type II collagen in chondrocytes from normal human femoral heads using real-time polymerase chain reaction. 18S rRNA was used as endogenous control, and the results are relative to a certain sample pertaining to the experiment. Separated maximum (SP) and minimum (IP) mechanical load areas were obtained from each femoral head. The horizontal bar shows the median, the box is the interquartile range, and the vertical lines show the atypical values. The Wilcoxon signed rank test was used to compare areas within the same joint. *Significant differences between poles, in MMP-3 values, were found, p < 0.05. No significant differences were found in MMP-1, aggrecan, and type II collagen gene expression. IP, inferior pole; MMP, matrix metalloproteinase; n, number of femoral heads used in the experiment; SP, superior pole.