Estrogen enhances progesterone-induced stimulation of proliferation and differentiation of osteoprogenitors in cell populations derived from adult human bone

先前的实验表明，来自成年雌性大鼠腰椎骨外植体的骨细胞群含有骨祖细胞，这些骨祖细胞需要地塞米松（Dex）或孕酮（Prog）才能增殖并分化为完全分化的成骨细胞。本研究是为了确定在大鼠身上发现的这些发现是否也适用于使用人体细胞的人类。首先，本研究旨在确定细胞群中Dex和prog反应性骨祖细胞的频率和/或数量。通过连续传代、极限稀释分析和菌落测定，确定了多达6次传代培养的祖细胞类型的频率和数量。在含有dex的培养基中，继代培养导致第二次传代细胞中dex应答的骨祖细胞总数比第一次传代细胞增加10%。从第三次传代开始，成骨细胞的出现频率呈线性下降，5次传代后出现了更多的成骨细胞，但没有出现成骨细胞。在含prog的培养基中也得到了类似的结果。Dex存在下的极限稀释分析表明，在第一次传代细胞中，1.81%的细胞代表集落形成单位-成纤维细胞，0.25%代表骨祖细胞。在Prog存在的情况下，在第一次传代细胞中，1.75%的细胞代表集落形成单位-成纤维细胞，0.09%的细胞代表骨祖细胞。其次，我们发现在性成熟后的女性骨骼中可以检测到prog依赖性群体，并且可以通过在含有17 β-雌二醇（10-9-10-8m）的培养基中培养成骨祖细胞来诱导。这表明prog依赖性骨祖细胞的存活和/或其增殖能力依赖于雌激素的存在。本文提出的结果与以下观点一致：在女性骨骼中，维持骨量的机制之一与雌激素和Prog对一类对Prog有反应的骨祖细胞的作用有关。这些发现可能为一类特定的prog依赖性骨祖细胞及其在人类骨骼中受雌激素调节的意义提供新的见解。少

Previous experiments have demonstrated that bone cell populations derived from explants of lumbar vertebral bone of adult female rats contain osteoprogenitors that require dexamethasone (Dex) or progesterone (Prog) to proliferate and differentiate into fully differentiated bone-forming osteoblasts. This study was conducted to determine whether these findings found in rat are also observed in human using human cells. First, the present study was undertaken to determine the frequency and/or number of Dex and Prog-responsive osteoprogenitors in cell populations. Frequencies and numbers of progenitor types were determined for up to six subcultures using continuous subculturing, limiting dilution analysis, and colony assays. In Dex-containing medium, subculturing resulted in a 10% increase in the total number of Dex-responsive osteoprogenitors in second subculture cells over first subculture cell. From the third subculture onward, the frequency of osteoprogenitors decreased in a linear mann … More er and none were observed after five subcultures. Similar results were obtained in Prog-containing medium. Limiting dilution analysis in the presence of Dex indicated that 1.81% of cells represented a colony forming unit-fibroblast and 0.25% represented an osteoprogenitor in first subculture cells. In the presence of Prog indicated that 1.75% of cells represented a colony forming unit-fibroblast and 0.09% represented an osteoprogenitor in first subculture cells. Second, we show that the Prog-dependent population can be detected in female bone after sexual maturation, and can be induced by culturing the osteoprogenitors in media containing 17 β-estradiol (10-9-10-8m). This suggested that the survival of the Prog-dependent osteoprogenitors and/or their ability to proliferate is dependent on the presence of estrogen. The results presented here are compatible with the view that in the female skeleton one of the mechanisms maintaining bone mass is related to effects of both estrogen and Prog on a class of osteoprogenitors responsive to Prog. These findings may provide new insight into the significance of a specific class of Prog-dependent osteoprogenitors and of their regulation by estrogen in the human skeleton. Less