PPARγ1 and PPARγ2 mRNA levels in normal and osteoarthritis human cartilage. RNA was extracted from normal (n = 7) and osteoarthritis (n = 8) cartilage, reverse transcribed into cDNA, and processed for real-time PCR. The threshold cycle values were converted to the number of molecules, as described in the Materials and methods section. Data were expressed as copies of the gene's mRNA detected per 1,000 glyceraldehyde-3-phosphate dehydrogenase copies. *p < 0.05 compared with normal samples. PPAR, peroxisome proliferator-activated receptor.