Expression and localization of estrogen receptor-β in annulus cells of the human intervertebral disc and the mitogenic effect of 17-β-estradiol in vitro

BACKGROUND Recent evidence suggests that estrogens exert effects in different tissues throughout the body, and that the estrogen receptor beta (ERbeta) may be important for the action of estrogen (17-beta-estradiol) on the skeleton. The cellular localization of ERbeta in the human intervertebral disc, however, has not yet been explored. METHODS Human disc tissue and cultured human disc cells were used for immunocytochemical localization of ERbeta. mRNA was isolated from cultured human disc cells, and RT-PCR amplification of ERbeta was employed to document molecular expression of this receptor. Cultured human disc cells were tested to determine if 17-beta-estradiol stimulated cell proliferation. RESULTS In this report data are presented which provide evidence for ERbeta gene expression in human intervertebral disc cells in vivo and in vitro. Culture of annulus cells in the presence of 10-7 M 17-beta-estradiol significantly increased cell proliferation. CONCLUSIONS These data provide new insight into the biology of cells in the annulus of the intervertebral disc.