骨髓基质细胞体内成骨分化研究

目的探讨将自体骨髓基质干细胞（BMSCs）移植到股骨头缺损坏死部位后能否成活、增殖，并向成骨分化，促进骨修复。方法取狗犬髂骨骨髓，体外培养扩增BMSCs，经5-溴脱氧尿嘧啶核苷（BrdU）标记，移植到股骨头骨缺损模型。术后5周取材。行大体组织观察，组织化学染色，免疫组化检测骨钙素、骨桥素。结果BMSCs能增加骨缺损区内的成骨量、提高骨基质矿化的程度和骨成熟度，提高成骨细胞分化特异性标记物骨钙素、骨桥素的表达。新骨形成越活跃的地方，BrdU阳性细胞数目越多，很多成骨细胞BrdU阳性，新骨形成区的很多血管壁也分布着BrdU阳性细胞。结论移植的骨髓细胞在股骨头内能成活，并能停留在骨坏死、缺损部位生长增殖。移植的BMSCs能分化成为多种细胞，包括成骨细胞、血管壁细胞等。BMSCs不但能直接通过分化成成骨细胞参与成骨，也能通过参与血管形成而促进成骨。

Osteogenic differentiation study of bone marrow stromal stem cells in vivo

Objective To evaluate whether the bone marrow stroma cells （BMSCs） transplanted to the defect of the femoral head can survive in situ, proliferate, differentiate into osteoblasts, increase bone formation, and repair the defect of the femoral head. Methods BMSCs were aspirated from skeletally mature dogs via iliac crest and separated by adher- ent cell cytopheresis. BMSCs were cultured in vitro, and collected from the second passage after marked with 5-bromode- oxyuridine （BrdU） to experiment. After capsulotomy, a reformed trapdoor was created in the posterolateral surface of the femoral head and a 8-ram-diameter and 10-ram-depth subchondral area of bone was removed. The bone removed was devitalized by microwave. The devitalized bone was transplanted in situ, in one lateral defect with the BrdU labelled BMSCs and in the contralateral defect without BMSCs. Samples were harvested at week 5. The precise location of BrdU-labeled BMSCs was observed by immunohistochemical staining. Gross tissue observation and histochemical stain were used. Osteoealcin and osteopontin were detected by immunohistochemical stain to defining the progressive osteogenic differentiation of osteoblasts. Results Gross tissue observation demonstrated that the defect transplanted with BMSCs were healing better than without BMSCs. Microhistology also demonstrated that the BMSCs increase bone formation and mineralization, im- prove osseous maturation, increase the number of fusiform shape mesenchymal cells and osteoblasts. The osteoblasts spe- cific differenciation markers are more intensive and abundant with BMSCs than without BMSCs. BrdU-labeled ceils were found in the defect. The more bone formation, the more BrdU-labeled cells. Many fusiform shape mesenchymal cells and osteoblasts are BrdU-labeled cells appeared, Many vessel wall cells are also BrdU-labeled cells in new bone zones. Con- clusion BMSCs can be transplanted to the defect of the femoral head can survive, live in situ and proliferate. BMSCs can differentiate into many types cells, including osteoblasts and vessel wall cells. BMSCs can increase bone and vessel formation, and repair the defect and osteonecrosis of the femoral head through differentiate into osteoblasts and vessel cells.