重建牙本质-牙髓复合体样结构的实验研究

Reconstruction of dentin-pulp complex structure by tissue engineering technology

目的采用组织工程学的方法重建牙本质-牙髓复合体样结构。方法以大鼠牙髓干细胞为种子细胞,将羟基磷灰石-磷酸三钙(HA-TCP)复合支架材料接种至裸鼠背部皮下,8周后取材进行组织学及免疫组织化学检测。结果移植物组织学切片可见支架材料孔隙内有3层组织结构,由外向内分别为矿化牙本质、前期牙本质及牙髓组织,其中牙本质小管明显,牙髓组织外层细胞密集,部分出现极化,呈现出成牙本质细胞样细胞特征。免疫组织化学染色证实人牙本质特异性蛋白、DMP1在前期牙本质区及成牙本质细胞样细胞为阳性表达。结论采用牙髓干细胞为种子细胞、HA-TCP为支架材料可成功构建牙本质-牙髓复合体样结构,为进一步进行牙齿组织工程再造奠定基础。

Objective To investigate the possibility of reconstruction of dentin-pulp complex by tissue engineering technology. Methods Rat dental pulp stem cells were seeded into HA-TCP scaffold and incubated for 20 hours in vitro. Then the cell-scaffold complex was implanted subcutaneously into the dorsal side of nude mice. 8 weeks postimplantation, the samples were extracted for histological and immunohistochemical examinations. Results Three strata of tissue were observed in the hole of HA-TCP scaffold. They were dentin-like tissue, predentin-like tissue and pulp-like tissue respectively from the inner surface of the pore to the center. Dentin tubules were obvious in predentin-like and dentin-like tissue lining from the pulp-like tissue through predentin-like tissue and dentin-like tissue. Cells localized along the edge of pulp-like tissue were dense and polarized, resembling odontoblasts. Immunohistochemical study demonstrated DSP and DMP1 expression in these odontoblast-like cells and in the area of predentin-like tissue. Conclusions Tissue-engineered rat dentin-pulp complex was reconstructed by seeding HA-TCP scaffold with rat dental pulp stem cells.