SLPI是一种弹性蛋白酶抑制因子。我们首次发现SLPI在小鼠分泌期的成牙本质细胞中呈现高度特异性表达并与基底膜共表达，因此SLPI可能在基底膜降解和成牙本质细胞分化中起调控作用。前期研究中发现SLPI降解基底膜且促进MMP分泌、细胞分化和BSP表达，推测SLPI可能通过PKC/ERK信号路径促进基底膜降解和通过BSP、DSP，Col I等分泌促进细胞分化。因此本项目拟以小鼠成牙本质细胞和发育小鼠模型为研究对象，首先利用基因转染技术探讨SLPI促进基底膜降解的机制；其次用建立的稳定细胞株，阐明SLPI促进细胞分化的机理；再次利用人工基底膜观察SLPI对基底膜降解和细胞分化的关系调节；最后利用原位杂交和免疫组化等技术确定SLPI与和牙本质发育相关基因的表达关系。最终阐明SLPI在牙本质发育中的调控机理，为牙齿再生研究提供实验依据和理论基础。

SLPI is secretory leucocyte protease inhibitor. We first discovered that SLPI is highly expressed in mouse odontoblast at secretory phase and co-expressed with basement membrane. Therefore SLPI may regulate basement membrane degradation and odontoblast differentiation. From preliminary study, we found that SLPI degraded basement membrane and promoted MMPs secretion, cell differentiation and BSP expression, we speculated that SLPI could promote basement membrane degradation through PKC/ERK signal pathway and promote odontoblast differentiation by the secretion of dentin matrix protein. Therefore, we intend to use MDPC-23 cell and mice models at different developmental stages. 1) we investigate the mechanism of basement membrane using transfection; 2) we set up the stable cell line to clarify the mechanism of promoting cell differentiation by SLPI. 3) we research the relation of basement membrane degradation and cell differentiation by SLPI using Matrigel; 4) we will confirm the relationship of SLPI to the gene expression involved in dentinogenesis using in situ and immunohistochemistry. Finally, we will clarify the mechanism of SLPI in dentinogenesis.