Expression of genes for estrogen receptors alpha and beta in human articular chondrocytes

Objective: To investigate the gene expression of estrogen receptor (ER) alp ha and ER beta in human articular chondrocytes. Methods: 16 articular cartilage specimens were obtained from 15 patients du ring surgery. Three of the specimens were from men and 13 from women; three from hip joints and 13 from knee joints; four were normal and 12 showed os teoarthritic cartilage. Total RNA was extracted from the articular chondroc ytes and the expression of both ER alpha and ER beta genes was investigated by the reverse transcription-polymerase chain reaction (RT-PCR) method. Results: Gene expressions of ER alpha were detected in all specimens and th ose of ER beta were found in 15 specimens by the RT-PCR method. There was a significant correlation between the amounts of ER alpha and ER beta. Expre ssion levels of both genes were significantly higher in men than in women. There were no significant differences in the expression levels of both ER g enes between the hip and knee joint sites, nor between normal and osteoarth ritic tissues. Conclusion: This study is to our knowledge the first to demonstrate the gen e expression of both ER alpha and ER beta in human articular chondrocytes. Since there are some functional differences between the two receptors, the effects of estrogen on cartilage metabolism should be elucidated by two dif ferent receptor mechanisms. (C) 1999 OsteoArthritis Research Society Intern ational.