Figure 3.

PGE₂ downregulates the expression of genes responsible for collagen cleavage, chondrocyte hypertrophy and inflammation. Relative expression with reference to glyceraldehyde-3-phosphate dehydrogenase is shown compared with controls for genes in osteoarthritic cartilages determined by real-time PCR analyses in explant cultures at 24 hours cultured in the presence or absence (control) of 10 pg/ml prostaglandin E₂ (PGE₂). Control bars are shown as 1.0 as required for relative quantification with the real-time PCR protocol. Means ± SD for all five patients (a–e) are shown in (f). Asterisks indicate significant differences from the control (P < 0.05). The age and sex of each patient are indicated. The average levels of PGE₂ in the medium in the gene expression studies were as follows: 62.3 ± 6.1 pg/ml for the 66-year-old female (a); 7.2 ± 1.9 pg/ml for the 53-year-old female (b); 0 pg/ml for the 67-year-old female (c); 65.7 ± 7.3 pg/ml for the 90-year-old female (d); and 30.4 ± 7.6 pg/ml for the 82-year-old female (e).