Orthopaedic Research Institute, St George Hospital Campus, University of New South Wales, Sydney, Australia.
Tohoku J Exp Med. 2010 May;221(1):61-8. doi: 10.1620/tjem.221.61.
In postmenopausal women, estrogen withdrawal results in decrease in bone density or osteoporosis. Osteoporosis leads to fracture and retards bone-healing response. Bone morphogenetic protein-7 (BMP-7), a member of the transforming-growth factor-beta superfamily, has been shown as a promising candidate that stimulates bone growth in its application to fracture healing. The purpose of this study was to determine whether BMP-7 could enhance bone formation in the absence of estrogen. Female rats underwent a controlled closed fracture at the midshaft of the right femur. The callus tissues were harvested from the fracture site eight days following the fracture, and were cultured in serum-free media. The explanted callus tissues were then treated with BMP-7, estrogen (E2) or both. We assessed bone formation by measuring alkaline phosphatase (AP) activity, expression of an osteogenic transcription factor, Runt-related transcription factor-2 (Runx2), production of nitric oxide (NO), and calcium mineralization. Supplementation of serum-free cultures with BMP-7 alone increased cell proliferation by twofold, caused a 6.5-fold increase in AP activity, and enhanced calcium mineralization after 48 h. Moreover, BMP-7 in combination with E2 caused a 8.2-fold increase in the AP activity. Runx2 protein expression was increased following stimulation with BMP-7 and E2. Interestingly, E2 induced the amount of NO production by twofold, whereas BMP-7 did not, either alone or with E2. Thus, BMP-7 could enhance early and late markers of bone fracture healing in callus explant cultures, except for NO. BMP-7 could be a promising growth factor in the treatment of fractures as a consequence of osteoporosis.
在绝经后妇女中，雌激素撤退会导致骨密度下降或骨质疏松症。骨质疏松症会导致骨折，并减缓骨愈合反应。骨形态发生蛋白 7（BMP-7）是转化生长因子-β超家族的成员，已被证明是一种有前途的候选药物，可通过刺激骨折愈合来促进骨生长。本研究旨在确定 BMP-7 是否可以在没有雌激素的情况下增强骨形成。雌性大鼠在右股骨中段进行了控制性闭合性骨折。骨折后 8 天，从骨折部位采集骨痂组织，并在无血清培养基中培养。然后，将离体骨痂组织用 BMP-7、雌激素（E2）或两者处理。我们通过测量碱性磷酸酶（AP）活性、成骨转录因子 Runt 相关转录因子 2（Runx2）的表达、一氧化氮（NO）的产生和钙矿化来评估骨形成。单独补充 BMP-7 可使无血清培养物中的细胞增殖增加一倍，AP 活性增加 6.5 倍，并在 48 小时后增强钙矿化。此外，BMP-7 与 E2 联合使用可使 AP 活性增加 8.2 倍。刺激 BMP-7 和 E2 可增加 Runx2 蛋白表达。有趣的是，E2 诱导 NO 产生量增加了一倍，而 BMP-7 无论是单独使用还是与 E2 联合使用，均未增加。因此，BMP-7 可以增强骨痂外植体培养物中骨折愈合的早期和晚期标志物，但不能增强 NO。BMP-7 可能是治疗骨质疏松性骨折的有前途的生长因子。
