Local mechanism of new bone formatior in bone grafting-interaotion between cells in the graft and cells in host-

虽然自体骨移植是目前可用的治疗方法。新骨形成的局部机制尚未得到明确的分析。本研究的目的是研究移植物和宿主细胞在新骨形成中的关系。我们以转基因大鼠和野生型大鼠为研究对象，建立了两种大鼠间取股骨移植到背部肌肉的异位等移植物模型。鹅分为两组，未处理组（实验组）和液氮处理组（对照组）。通过免疫组化检测成骨细胞和破骨细胞的来源，实时RT-PCR和原位杂交检测BMP信号的时空表达。实验组于移植后第7天髓管内出现异位新骨形成，并进行骨重塑。对照组未见骨形成。第7天，成骨细胞主要来源于移植物。第14天来自宿主的成骨细胞增多。在第42天，几乎所有的成骨细胞都被宿主取代。BMP-4瞬时升高。实验组中存在BMPRIA、2和noggin mRNA，对照组中仅存在BMPRIA和2 mRNA。第7天移植物细胞表达BMP-4 mRNA，第14天移植物细胞和宿主细胞均表达BMP-4 mRNA。我们的结果首次表明移植物细胞通过表达bmp - 4mrna诱导宿主细胞成骨的可能性。

Although autogenous bone grafting is currently available treatment. local mechanism of new bone formation has riot been analyzed clearly. The aim of this study was to examine the relationship between cells in the graft and host for new bone formation. We used GFP transgenic rats and wild-type rats, and ectopic isograft model that harvested femur was transplanted into back muscles between these kinds of rats was established. Gratis were divided into two groups, without treatment(experimental group) and treated by liquid nitrogen(control croup). Specimens were examined by immunohistochemistry for origin of osteoblast and osteoclast, real time RT-PCR, and in situ hybridization for temporal and spatial expression of BMP signaling. Eclopic new bone formation was found in the medullary canal at day 7 after grafting, and remodeling was followed in experimental group. No bone formation was found in control group. At day 7, osteoblasts were mainly originated from graft. Osteoblasts originated from host increased at day 14.and almost all of the osteoblasts were replaced by host at day 42.Transient increase of BMP-4.BMPRIA, 2, and noggin mRNA was found in experimental group, but only BMPRIA and 2 mRNA in control group. BMP-4 mRNA was expressed in graft cells at day 7 and in both graft and host cells at day 14.Collectively our results indicated the possibility for the First time that cells in graft induced host cells to bone formation by expressing BMP-4 mRNA.