中文摘要：

目的 评价牙本质涎磷蛋白（DSPP）转基因修饰骨髓问质干细胞（BM-MSC）后，对BM-MSC生物学特性及DSPP表达的影响。方法构建含小鼠DSPP基因的真核表达载体pcDNA3．1（＋）／DSPP，用脂质体介导转染大鼠BM-MSC；RT-PCR检测转染后细胞的Pax-9和DMP-1基因表达情况；检测转染细胞矿化诱导后Von Kossa钙盐染色计算单位面积钙结节形成率。结果成功构建DSPP真核表达载体pcDNA3．1（＋）／DSPP，酶切后得到3．0kb和5．4kb的片段，与回收的目的基因和载体基因片段大小相符；经转染BM-MSC后24h可见DSPP基因表达，48h后可见有Pax-9基因表达，无DMP-1基因表达；转基因后的BM-MSC免疫组化染色显示DSPP阳性；转染细胞矿化诱导后钙结节形成率高于未转染细胞。结论BM-MSC转基因表达DSPP能够增强其矿化能力，并诱导牙齿发育相关基因的表达，提示DSPP可能在牙齿发育早期具有一定作用。

英文摘要：

Objective To evaluate the expression of dentin sialophosphoprotein （DSPP） in transfected rat bone marrow mesenchymal stem cells （BM-MSC） and the influence of the transfection. Methods Plasmid containing mice dentin DSPP was constructed by using the cytomegalovirus （CMV） promoter and then transfected the cultured BM-MSC by lipofectamine; The expression of Pax-9 and dentin matrix protein 1 （ DMP1 ） gene of transfected BM-MSC were detected by RT-PCR. The expression of DSPP was examined by immunocytochemical staining, and the formation ratio of mineralized nodules of transfected BM-MSC was compared with untransfected ones after mineralized induction. Results The constructed pcDNA3.1 （＋）/mDSPP could produced 3. 0 kb and 5.4 kb fragments , DSPP gene and Pax9 gene were expressed 24 h and 48 h respectively , after BM-MSC were transfected Pax-9 gene was exprssed , but DMP1 gene was not; Immunohistochemical staining shewed that DSPP was positive in transfected BM-MSC; The formation ratio of mineralized nodules of transfected BM-MSC was higher than that of untransfected ones after mineralized induction. Conclusions The expression of mice DSPP in BM-MSC by gene transfection can induce the expression of tooth development-associated gene Pax9 and enhance the formation of mineralized nodules, which suggests that DSPP gene might induce odontogenic differentiation of BM-MSC.