title: Localization of estrogen receptors alpha and beta in the articular surface of the rat femur.
abstract: It has been suggested that the degradation of the articular cartilage and osteoarthritis (OA) are associated with gender and the estrogen hormone. Although many investigators have reported the presence of the estrogen receptors (ERs) alpha and beta in the articular cartilage, the localization of these receptors and the difference in their in vivo expression have not yet been clearly demonstrated. We performed immunofluorescence staining of ERalpha and ERbeta to elucidate the localization of the ERs and to note the effects of gender and the aging process on these receptors. The results revealed that ERalpha and ERbeta were expressed in the articular cartilage and subchondral bone layers of adult rats of both sexes. We also observed the high expression of these receptors in immature rats. In contrast, their expression levels decreased in an ovariectomised model, as a simulation of postmenopause, and in aged female rats. Therefore, this study suggests the direct effects of estrogen and ER expression on articular surface metabolism.
authors: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
authors: Yasushi
authors: Y
authors: Oshima
authors: Ken-Ichi
authors: K
authors: Matsuda
authors: Atsuhiko
authors: A
authors: Yoshida
authors: Nobuyoshi
authors: N
authors: Watanabe
authors: Mitsuhiro
authors: M
authors: Kawata
authors: Toshikazu
authors: T
authors: Kubo