Study on the effect of colony stimulating factor on bone metabolism

(1)在过量表达G-CSF的转基因小鼠中，BMP-2诱导的异位骨形成受到损害。在G-CSF小鼠中，间充质细胞的诱导和软骨形成在异位骨形成的早期阶段减少。植入BMP-2 3周后，G-CSF小鼠异位骨中板层结构未成熟，钙含量降低。异位骨中I型胶原、骨桥蛋白和骨钙素的mRNA表达水平在G-CSF小鼠和它们的仔鼠对照组之间没有显著差异。然而，异位骨基质中骨钙素蛋白在G-CSF小鼠中的表达低于同胎小鼠。(2)研究了维生素K2(甲肾上腺素)(MK4)对发育过程中骨表型的影响。以含0.05 mg MK-4/100g或20.0 mg MK-4/100g的饲料喂养小鼠12周，不改变小鼠的骨长，无论小鼠的类型或饮食。外周定量计算机断层扫描(PQCT)显示经MK-4处理的小鼠骨骼CT值升高。(3)利用体外细胞培养系统研究了G-CSF小鼠骨骼中细胞和分子的异常。在这里，我们证明转基因小鼠骨髓中的成骨细胞前体细胞数量减少，但具有更强的支持破骨细胞生成的能力。在转基因小鼠中，骨髓细胞中的CFU-GM显著增加，而骨髓细胞中可能含有破骨细胞前体细胞。此外，核因子受体激活剂RANK B配体(RANK配体)在转基因小鼠成骨细胞中的表达明显降低。

(1) We have shown that ectopic bone formation induced by BMP-2 was impaired in transgenic mice overproducing G-CSF. In G-CSF mice, induction of mesenchymal cells and chondrogenesis diminished at early stage of ectopic bone formation. The lamellar structure was immature and the calcium content was decreased in the ectopic bone of G-CSF mice 3 weeks after the implantation of BMP-2. There was no significant difference in mRNA expression levels of type I-collagen, osteopontin, and osteocalcin in the ectopic bone among G-CSF mice and their littermate controls. However, the expression of osteocalcin protein in the ectopic bone matrix was less in G-CSF mice than that in littermates.(2) The effect of vitamin K2 (menatetrenone) (MK4) on bone phenotypes during development was examined. Mice were fed chow k containing either 0.05mg MK-4/100g or 20.0mg MK-4/100g for twelve weeks as the control and experimental diets, respectively.This treatment did not change bone length, irrespective of the type of mice or diet. Peripheral quantitative computed tomography(pQCT)revealed an increase of the CT value in bone in MK-4 treated mice.(3) We investigated the cellular and molecular abnormality in the bone of G-CSF mice using ex-vivo cell culture system. Here we demonstrate that osteoblast progenitors in bone marrow oftransgenic mice are diminished in number but possess increased ability to support osteoclastgenesis. CFU-GM in bone marrow cells, which is blieved to contain osteoclast progenitors, was significantly increased in transgenic mice. In addition, the expression of receptor activator of nuclear factor- κ B ligand (RANK ligand ; RANKL) was rather decreased in osteoblasts oftransgenic mice.