1 Department of Conservative Dentistry and Periodontology, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria.
2 Austrian Cluster for Tissue Regeneration, Vienna, Austria.
J Biomater Appl. 2019 Apr;33(9):1277-1284. doi: 10.1177/0885328218821042. Epub 2019 Feb 13.
Thixotropic clays have favorable properties for tissue regeneration. Hypoxia mimetic agents showed promising results in pre-clinical models for hard and soft tissue regeneration. It is unclear if clays can be used as carrier for hypoxia mimetic agent in a periodontal regenerative setting. Here, we tested the response of human fibroblasts of the periodontal soft tissue to synthetic clay hydrogels and assessed hypoxia mimetic agent release. Cells were cultured on synthetic clay hydrogels (5.00%-0.15%). We assessed viability and differentiation capacity with resazurin-based toxicity assays, MTT staining, Live-Dead staining, and alkaline phosphatase staining. To reveal the response of fibroblasts to hypoxia mimetic agent-loaded clay hydrogels, cells were exposed to clay supplemented with dimethyloxalylglycine, deferoxamine, l-mimosine, and CoCl. Supernatants from hypoxia mimetic agent-loaded clay hydrogels were harvested and replaced with medium at hour 1, 3, 6, 24, 48, and 72. To reveal the hypoxia mimetic capacity of supernatants, vascular endothelial growth factor production in the fibroblasts was assessed in the culture medium. Our data show that clay did not induce relevant toxic effects in the fibroblasts which remained capable to differentiate into alkaline phosphatase-positive cells at the relevant concentrations. Fibroblasts cultured on clay hydrogel loaded with dimethyloxalylglycine, deferoxamine, l-mimosine, and CoCl remained vital, however, no significant increase in vascular endothelial growth factor levels was found in the culture medium. Only dimethyloxalylglycine-loaded clay supernatants taken in the first hours stimulated vascular endothelial growth factor production in fibroblasts. In conclusion no pronounced toxic effects of synthetic clay were observed. Supplementation with dimethyloxalylglycine leads to hypoxia mimetic activity. This pilot study provides first insights into the impact of synthetic clay on periodontal tissue.
触变性粘土具有促进组织再生的良好特性。缺氧模拟剂在硬组织和软组织再生的临床前模型中显示出有希望的结果。目前尚不清楚粘土是否可以作为缺氧模拟剂在牙周再生环境中的载体。在这里，我们测试了人牙周软组织成纤维细胞对合成粘土水凝胶的反应，并评估了缺氧模拟剂的释放。细胞在合成粘土水凝胶（5.00%-0.15%）上培养。我们使用基于 Resazurin 的毒性测定、MTT 染色、Live-Dead 染色和碱性磷酸酶染色来评估细胞活力和分化能力。为了揭示成纤维细胞对负载缺氧模拟剂的粘土水凝胶的反应，将细胞暴露于补充有二甲草酰甘氨酸、去铁胺、L-千里光碱和 CoCl 的粘土中。在第 1、3、6、24、48 和 72 小时收获负载缺氧模拟剂的粘土水凝胶的上清液并更换培养基。为了揭示上清液的缺氧模拟能力，评估了血管内皮生长因子在纤维母细胞中的产生。我们的数据表明，粘土在相关浓度下不会对成纤维细胞产生相关毒性作用，成纤维细胞仍能够分化为碱性磷酸酶阳性细胞。在负载二甲草酰甘氨酸、去铁胺、L-千里光碱和 CoCl 的粘土水凝胶上培养的成纤维细胞保持活力，但在培养基中未发现血管内皮生长因子水平显著增加。只有在最初几小时内摄取的负载二甲草酰甘氨酸的粘土上清液才能刺激成纤维细胞中血管内皮生长因子的产生。总之，未观察到合成粘土的明显毒性作用。补充二甲草酰甘氨酸可导致缺氧模拟活性。这项初步研究首次提供了关于合成粘土对牙周组织影响的见解。
