The Hormonal Milieu in Early Stages of Bone Cell Differentiation Modifies the Subsequent Sex-Specific Responsiveness of the Developing Bone to Gonadal Steroids
作者:E. Berger、I. Bleiberg、Y. Weisman、B. Lifschitz-Mercer、L. Leider-Trejo、A. Harel、A. M. Kaye、D. Somjen
DOI:10.1359/jbmr.2001.16.5.823
日期:——
We have established previously that rat bone tissue, as well as rat and human‐derived bone cells in culture, show a sex‐specific response to gonadal steroids in stimulation of the specific activity of the BB isozyme of creatine kinase (CK) and DNA synthesis. This response could be modified by manipulation of the endocrine environment during early stages in rat development. To further examine the influence of changing hormonal steroid milieu and vitamin D status on the action of gonadal steroids in developing bone tissue, we used two models of ectopic bone formation: demineralized tooth matrix (DTM) implanted under the skin, and femoral bone marrow (BM) transplanted under the kidney capsule of a syngeneic recipient mouse. The response to gonadal steroids in ossicles developed from implanted DTM depended on the recipient's gender; injection of estradiol 17β (E2; 5 μg) into young female mice 21 days after DTM implantation increased, 24 h later, CK activity in the newly formed ossicles by ∼60%, whereas injection of dihydrotestosterone (DHT; 50 μg) had no effect on CK activity. In contrast, in male mice, DHT but not E2 increased CK activity in the ossicles by ∼50%. This sex‐specific response was abolished in gonadectomized mice resulting in a similar response of the ossicles to both E2 and DHT. When DTM was implanted into vitamin D‐deficient female mice, there was a lower basal CK activity and a significantly diminished response to E2 in the newly formed bone tissues. When BM, which contains mesenchymal and stromal cells and committed osteoprogenitor cells, was transplanted into 6‐week‐old intact or gonadectomized female or male mice, the response of the newly formed bone ossicles, 21 days after transplantation, to E2 or to DHT was according to the gender of the donor. Bone formed from BM obtained from female mice responded to E2 only and those formed from male BM responded to DHT only. Ossicles developed from BM obtained from gonadectomized mice showed lack of response to either gonadal steroid. Furthermore, only ∼25% of the BM transplants obtained from castrated (CAST) male donors developed into ossicles. Ossicles formed from BM obtained from vitamin D‐deficient female donors showed lack of response to gonadal steroids. These findings suggest that the manipulation of the hormonal milieu in early stages of the differentiation sequence of bone cells modifies the subsequent selective responsiveness of the developing bone tissue to gonadal steroids.
我们之前已经证实,大鼠骨组织以及培养中的大鼠和人类骨细胞对性腺类固醇有性别特异性反应,即刺激肌酸激酶(CK)BB 同工酶的特异性活性和 DNA 合成。在大鼠发育的早期阶段,这种反应可能会因内分泌环境的变化而改变。为了进一步研究激素类固醇环境和维生素 D 状态的变化对性腺类固醇作用于发育中骨组织的影响,我们使用了两种异位骨形成模型:植入皮下的去矿物质牙基质(DTM)和移植到合成受体小鼠肾囊下的股骨髓(BM)。植入 DTM 后 21 天,向幼年雌性小鼠注射雌二醇 17β(E2;5 μg),24 小时后,新形成的骨小泡中的 CK 活性增加了 60%,而注射双氢睾酮(DHT;50 μg)对 CK 活性没有影响。相反,在雄性小鼠中,DHT 而不是 E2 会使骨小梁中的 CK 活性增加 50%。在性腺切除的小鼠中,这种性别特异性反应被取消,导致听骨对 E2 和 DHT 的反应相似。当将 DTM 植入维生素 D 缺乏的雌性小鼠体内时,新形成的骨组织中的基础 CK 活性较低,对 E2 的反应也明显减弱。当将含有间充质细胞、基质细胞和坚定的成骨细胞的 BM 移植到 6 周大的完整或性腺切除的雌性或雄性小鼠体内时,移植 21 天后新形成的骨小梁对 E2 或 DHT 的反应与供体的性别有关。由雌性小鼠的骨髓形成的骨只对E2有反应,而由雄性小鼠的骨髓形成的骨只对DHT有反应。由性腺切除小鼠的骨髓形成的骨小梁对任何一种性腺类固醇都没有反应。此外,从阉割(CAST)雄性供体获得的骨髓移植只有 25% 发育成骨小泡。从维生素 D 缺乏的女性供体获得的骨髓形成的骨小体对性腺类固醇缺乏反应。这些研究结果表明,在骨细胞分化序列的早期阶段对激素环境的操纵会改变发育中的骨组织随后对性腺类固醇的选择性反应。