title: Gene expression of stromelysin and aggrecan in osteoarthritic cartilage.
abstract: OBJECTIVE
  To analyze cartilage gene expression of patients with osteoarthritis (OA) in correlation with radiographic and histological findings.
  
  
  METHODS
  Twenty-one patients with OA of the knee admitted for total knee replacement were analyzed clinically and radiographically by the Kellgren and Lawrence system. During surgery, cartilage samples from the medial and lateral condyles and tibial plateaus were harvested separately. Specimens were analyzed histologically (Mankin score) and total RNA was extracted directly from cartilage tissue. Steady state levels of stromelysin (MMP-3), aggrecan (AGG) and the house-keeping gene beta-actin were measured using quantitative PCR.
  
  
  RESULTS
  Histology of medial and lateral knee compartments corresponded to radiographic changes (Spearman correlation coefficient: r = 0.7 (p < 0.01)). There was a positive correlation between MMP-3 and AGG gene expression (r = 0.4; p < 0.01). We found considerable variation of expression levels of MMP-3 and AGG and no correlation of gene expression with histological or radiographic scoring.
  
  
  CONCLUSIONS
  The positive correlation between AGG and MMP-3 suggests a common regulation of anabolic and catabolic metabolism. There was no simple dependency between gene expression and histological and radiological findings in cartilage.
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D053674:Aggrecans; D001175:Arthrography; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D016326:Extracellular Matrix Proteins; D005260:Female; D015870:Gene Expression; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging; D037181:Lectins, C-Type; D008297:Male; D019278:Matrix Metalloproteinase 3 / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000235:genetics* / Q000378:metabolism; D011509:Proteoglycans / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D053674:Aggrecans; D016326:Extracellular Matrix Proteins; D037181:Lectins, C-Type; D011509:Proteoglycans; D012333:RNA, Messenger; D019278:Matrix Metalloproteinase 3