骨形态发生蛋白7诱导骨膜细胞体外构骨的超微结构

Ultrastructure of periosteal cells induced by bone morphogenetic protein 7 in vitro

背景:骨形态发生蛋白被证实有成骨诱导作用,然而关于骨形态发生蛋白7诱导骨膜细胞成骨的超微结构研究尚未见报道。目的:观察骨膜细胞经成骨因子骨形态发生蛋白7诱导后的生物活性及超微结构。方法:实验取材于成人胫骨。分离出原代骨膜细胞后行常规体外培养,实验分为实验组和对照组。实验组加入骨形态发生蛋白7和细胞培养辅助剂,对照组仅仅加入了成骨细胞培养辅助剂。每组分别在第5,10,15天设3个时间点,每个时间点设3个样本,分别行钙结节的染色及采用相差显微镜观察大体形态结构,在透射电镜下观察超微形态结构。结果与结论:实验组和对照组形成的成骨细胞增殖良好,形态一致。细胞早期呈梭形,立体感强,饱满透明,分裂期呈短柱状或立方形,电镜下见成骨细胞内有大量的粗面内质网和高尔基复合体;后期细胞由长梭形逐渐变成宽梭和不规则形,后期射透电镜下可见细胞内有大量基质小泡,有膜包被,胞质内上有碱性磷酸酶及钙结合蛋白,泡内有钙盐结晶,成骨细胞的基底部和侧面出现突起与邻近的骨细胞突起相连。由骨形态发生蛋白7诱导的成骨细胞在体外增殖更快,细胞分裂及成骨速度更快。结果提示骨形态发生蛋白7在体外培养中具有明显增强成骨细胞增殖的能力。

BACKGROUND：Study confirms that bone morphogenetic protein can induce osteogenesis;however the ultrastructure of periosteal cells induced by bone morphogenetic protein-7 remains poorly reported. OBJECTIVE：To study the bioactivity and ultrastructure of periosteal cells induced by bone morphogenetic protein-7 in vitro. METHODS：The primary periosteal cells isolated from adult tibial bone were in vitro cultured, and then divided into experimental group and control group. In the experimental group, cells were cultured with bone morphogenetic protein-7 and culture adjuvant;while cells in the control group were only cultured with the adjuvant. Three samples in each group were tested at 5, 10, 15 days, respectively. The general structure of cultured cells was observed using von Kossa staining, and the ultrastructure was observed under transmission electron microscopy. RESULTS AND CONCLUSION：The periosteal cells in the two groups grew wel in vitro, showing uniform morphology. Early cells were spindle-shaped, with strong three-dimensional sense and ful transparency;mitotic cells were short columnar or cubic shaped, there were a lot of rough endoplasmic reticulum and Golgi complex in osteoblasts under electron microscope. Later stage of cells developed from long fusiform into wide shuttle and irregular shape, there were a large number of matrix vesicles within the cells under the electron microscope. The membrane coating, alkaline phosphatase and calcium-binding protein in the cytoplasm, as wel as calcium crystals were found. The osteogenesis basement and lateral sides appeared projections, which were connected with adjacent bone cells. Induction of bone morphogenetic protein-7 in vitro promotes the osteoblasts proliferation, division and bone formation speed. The results suggest that bone morphogenetic protein-7 can significantly enhance the proliferation ability of osteoblasts in vitro.