Background/Aim: To optimize the expansion of human dental pulp cells in vitro by exploring several cryopreservation methodologies. Materials and Methods: The intra-dental pulp tissues from healthy subjects were extracted and divided into three separate tissue segments, which were randomly divided into the three following groups; the fresh group, the 5% DMSO group, and the 10% DMSO group. In the fresh group, dental pulp cells were directly cultivated as primary cultures, whereas in the DMSO groups, the dental pulp cells were cultivated from cryopreserved pulp tissue segments one month later. Results: The cell yield and the time it took for the cells to grow out of the pulp tissue and attach to the culture plate varied among the three groups; the 5% DMSO group was inferior to the fresh group but superior to the 10% DMSO group (p<0.05). Moreover, no differences were found at the 1st passage amongst the three groups regarding the following aspects (p>0.05); colony formation rate and cell survival rate. Furthermore, no differences were noted at the 3rd passage regarding the following aspects (p>0.05); proliferation ability, cell growth curve and surface marker expression of dental pulp cells. Conclusion: Five percent DMSO may be the most optimal condition for tissue storage to preserve stem cells in situ.

中文翻译：

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在不同冷冻条件下体外扩增人牙髓细胞

背景/目的：通过探索几种冷冻保存方法，优化体外人牙髓细胞的扩增。材料与方法：提取健康受试者的牙髓组织，将其分为三个独立的组织段，随机分为以下三组；新鲜组、5% DMSO 组和 10% DMSO 组。在新鲜组中，牙髓细胞直接作为原代培养物进行培养，而在 DMSO 组中，牙髓细胞是在 1 个月后从冷冻保存的牙髓组织切片中培养出来的。结果：三组之间的细胞产量和细胞从牙髓组织中生长出来并附着在培养板上的时间不同；5% DMSO 组次于新鲜组，但优于 10% DMSO 组（p<0.05）。而且，三组在第一次传代时在以下方面没有发现差异（p>0.05）；集落形成率和细胞存活率。此外，第 3 段在以下方面没有发现差异（p>0.05）；牙髓细胞的增殖能力、细胞生长曲线和表面标志物表达。结论：5% 的 DMSO 可能是组织储存以原位保存干细胞的最佳条件。