成骨细胞特异性钙粘蛋白修饰的骨基质材料对兔MSCs黏附及成骨分化能力的影响

目的 探讨成骨细胞特异性钙粘蛋白(OB-Cadherin)蛋白涂布脱钙骨基质材料对兔间充质于细胞的黏附、增殖及成骨分化能力的影响.方法 将第二代兔间充质干细胞分别与经OB-Cad-herin修饰的同种异体冻干脱钙骨基质和未经OB-Cadherin修饰的骨基质材料复合,体外构建组织工程骨,通过比较材料上的细胞密度计算细胞的上架率和上架细胞数;检测支架细胞ALP和骨钙素的表达来反映细胞的增殖、黏附及成骨分化能力.通过相差显微镜、扫描电镜观察了解细胞在材料中的黏附、生长情况.所得数据计量资料以均数±标准差(x±s)表示,采用成组t检验和配对-t检验,以P<0.05为差异具有统计学意义.结果 培养7 d,14 d,21 d两组细胞的增殖程度差异无统计学意义;20 h后对照组细胞上架率低,为(35.56±1.75)%,上架细胞数低,每块材料上的细胞不足2.7×104;OB-Cadherin修饰组的细胞上架率稳定在80%以上,明显高于对照组(P<0.01);每块材料上的上架细胞数可高达5.0×105,与对照组相比,差异具有统计学意义(P<0.01).OB-Cadherin修饰组的细胞黏附率显著高于对照组;培养7 d后OB-Cadherin修饰组细胞ALP和骨钙素的表达增高,14 d后已显著高于对照组,ALP的活性达最高值,经配对t检验差异具有统计学意义(P<0.01);14 d时骨钙素免疫组化阳性率OB-Cadherin修饰组为(71±11)%,对照组为(49±8)%,差异具有统计学意义.结论 OB-Cadherin修饰的骨基质材料对间充质干细胞的增殖无明显促进作用,但能提高细胞的黏附性,促进向成骨细胞的分化.

Effects of demineralized bone matrix coated with OB-Cadherin on the capability of mesenchymal cells for adhesion and osteogenic differentiation

Objective To evaluate the adhesion, proliferation and osteogenic differentiation of rabbits' mesenchymal stem cells (MSCs) cultured in demineralized bone matrix coated with OB-Cadherin. Method The second generation of MSC s were seeded onto the OB-Cadherin cover over allogenic frozen-dried demineralized bone matrix(FDBM) and the FDBM without OB-Cadhefin as control, and then both were cultured separably in vitro. The densities of seeded cells, the adhesion rate were measured, and their ALP activity was assayed in order to take it as an index of cell adhesion, proliferation and osteogenic differentiation. The growth and adhension of MSCs on the FDBM was observed and evaluated microscopically and electronic scanning microscopically. Data were ex-pressed as means and standard deviation (x±s), and were analyzed with SPSS 12.0. Independent-Sanples T-test and Paired t test was used, and P<0.05 indicated statistically significant. Results There was no significant dif-ference in cell proliferation between modified FDBM and unmodified FDBM cultured fot 7, 14, 21 d. ays. After culture for 20 hours, the adhesion rate in the control group was (35.56±1.75)%, the densities of seeded cells were less than 2.7×104. The adhesion rate of cells in the modified group was consistent at 80%, whereas the densities of seeded cells were as high as 5.0×105 compared with control group (P<0.01). After cultured for 20 hours, the efficiency of cell adhesion in the modified FDBM was higher than that in the unmodified FDBM. After cultured for 7 days, the cultured MSC on modified FDBM expressed higher AIP activity, and after cultured for 14 days, the ALP activity on modified FDBM was much higher than that on unmodified FDBM (p<0.01). After cultured for 14 days, osteocalcin immunohistochemical positive rate of modified group was (71±11)%, while that of the control group was(49±8)% with significant difference Conclusion OB-Cadherin enhances cell adhesion to FDBM and promotes MSC to differentiate to osteoblast, but no obvious effects d OB-Cadherin on cell proliferation were observed.