Copyright information:Taken from "Fibroblast activation protein alpha is expressed by chondrocytes following a pro-inflammatory stimulus and is elevated in osteoarthritis"Arthritis Research & Therapy 2006;8(1):R23-R23.Published online 3 Jan 2006PMCID:PMC1526559. Total RNA was extracted from osteoarthritic hip cartilage (n = 14) and phenotypically normal hip cartilage from patients with femoral neck fracture (n = 12). gene expression was determined by real-time PCR as described in Materials and methods. The data are presented relative to . gene expression is significantly higher in osteoarthritic cartilage (OA) compared to normal cartilage (= 0.0009).