釉质基质蛋白对乳牙牙髓干细胞体外增殖、分化能力的影响

目的：研究釉质基质蛋白（enamel matrix proteins，EMPs）对人脱落乳牙牙髓干细胞（stem cells from hu—man exfoliated dediduous teeth，SHED）体外增殖分化能力的影响。方法：利用酶消化法联合组织块法获得脱落乳牙牙髓干细胞，并进行形态学观察。三氯乙酸法制备EMPs，用不同浓度的EMPs对SHED进行诱导，利用四唑盐比色法（MTT）检测并分析诱导后的SHED增殖活性的变化，检测经诱导后的培养液中碱性磷酸酶（ALP）。RT—PCR检测牙本质涎磷蛋白（dentin sialophosphoprotein，DSPP）及牙本质基质蛋白1（dentin matrix protein1，DMP-1）的mRNA表达。结果：人脱落乳牙牙髓干细胞呈集落生长，并且在体外具有一定的自我增殖能力。EMPs对乳牙牙髓干细胞的增殖无明显影响，而能够显著提高ALP的活性，并呈现一定的剂量依赖性。经EMPs诱导后，细胞相对高表达DSPP、DMP-1mRNA。结论：EMPs对于SHED向成牙本质样分化具有积极作用。

Effects of EMPs on Proliferation and Differentiation of SHED in Vitro

Objective： To investigate the effect of EMPs on proliferation and differentiation of SHED in vitro. Methods： The stem cells were collected from human exfoliated dediduous teeth by enzyme digestion and tissue ex- plant method. We separated EMPs from bovine teeth with acetic acid method. The proliferation activity was exam- ined by MTT assay. ALP, DSPP, and DMP--1 mRNA were analyzed to examine the differentiation activity after inducement. Results： The stem cells from human exfoliated dediduous teeth showed colony growth and have the a- bility of certain self renewal. EMPs had no effect on cell proliferation, but could significantly improve the ALP ac- tivity and showed a dose--dependent manner. The expression of DSPP and DMP1 mRNA in effected ceils in- creased. Conclusion.. EMPs plays a positive role in the differentiation of SHED to dentin--like cells.