掺锶对磷酸锶钙骨支架体外细胞毒性的影响研究

Effect of adding strontium on the cytotoxicity of a strontium-calcium phosphate scaffold in vitro

背景:通过离子置换的方法,将锶离子部分置换磷酸钙骨支架的钙离子,有望能改善骨支架材料的骨诱导性。但是,目前尚不知道掺锶是否对磷酸钙骨支架材料有体外细胞毒性的影响。目的:探讨掺锶对磷酸锶钙骨支架体外细胞毒性的影响。方法:骨支架的原始反应物包括粉剂和液体。粉剂包括磷酸四钙(tetracalcium phosphate,TTCP)、无水磷酸二钙(dicalcium phosphate anhydrous,DCPA)、磷酸氢锶(strontium hydrogen phosphate,DSPA)。液体为含20wt%的柠檬酸和12wt%的聚乙烯吡咯烷酮混合液,调整液体p H为4。粉剂与液体按2 g/ml比例混合,固化后制备出骨支架。本研究按锶/(锶+钙)[Sr/(Sr+Ca)]离子摩尔百分比0、5%、10%和20%分为4组:Sr-0组、Sr-5组、Sr-10组和Sr-20组。然后进行细胞毒性实验、骨支架表面细胞增殖和碱性磷酸酶活性实验,并观察细胞在材料表面的形态学特征。结果:各组浸提液均没有细胞毒性。MG-63细胞在材料表面增殖良好,开始呈扁平状,并通过较长的突触连接支架表面。在培养后期,细胞全部覆盖骨支架表面。掺锶促进细胞增殖,并提高碱性磷酸酶活性。结论:添加了锶离子的磷酸锶钙骨支架材料没有细胞毒性,反而提高了细胞的碱性磷酸酶活性。

Background：It is hypothesized that ions substitution of calcium by strontium（Sr） in calcium phosphate scaffold results in osteoconductivity of the biomaterial.However,the effect of adding strontium on the cytotoxicity of the calcium phosphate scaffold is unknown.Objective：To investigate the effect of adding strontium on the cytotoxicity of a strontiumcalcium phosphate scaffold in vitro.Methods：The strontium-calcium phosphate scaffold was made by mixing the original power which consisted of tetracalcium phosphate（TTCP）,dicalcium phosphate anhydrous（DCPA） and strontium hydrogen phosphate（DSPA）,and the liquid which consisted of 20 wt% citric acid and 12 wt% polyvinylpyrrolidone K-30,in a ratio of2 g/ml.There were four groups designed as Sr-0,Sr-5,Sr-10,and Sr-20,according to the molar ratio of Sr/（Sr＋Ca） being 0,5%,10%,and 20% in the power phase,respectively.The cytotoxicity,cell proliferation,alkaline phosphatase（ALP） activity and the cell morphology on the scaffold surface were studied.Results：There was no cytotoxicity in all of the groups.The MG-63 cells attached to the scaffold surface.Higher cell proliferation rate,as well as higher ALP activity were observed in the strontium groups as compared with the group which was free of strontium.Conclusions：The strontium-calcium phosphate scaffold is not cytotoxic when a certain amount of strontium is added.Better MG-63 cell proliferation and higher ALP activity are observed in the strontium group in this study.