Yu Yang, Bi Chun-Sheng, Wu Rui-Xin, Yin Yuan, Zhang Xi-Yu, Lan Ping-Heng, Chen Fa-Ming
State Key Laboratory of Military Stomatology, Department of Periodontology, School of Stomatology, Fourth Military Medical University, 145th West Changle Road, Xi'an, Shaanxi, China.
National Clinical Research Center for Oral Diseases, Department of Periodontology, School of Stomatology, Fourth Military Medical University, Xi'an, China.
Cell Tissue Res. 2016 Nov;366(2):311-328. doi: 10.1007/s00441-016-2437-3. Epub 2016 Jun 15.
In this study, we extensively screened the in vitro and in vivo effects of PDLSCs following short-term inflammatory and/or hypoxic pretreatments. We found that the 24-h hypoxic pretreatment of PDLSCs significantly enhanced cell migration and improved cell surface CXCR4 expression. In addition, hypoxia-pretreated PDLSCs exhibited improved cell colony formation and proliferation. Cells that were dually stimulated also formed more colonies compared to untreated cells but their proliferation did not increase. Importantly, the hypoxic pretreatment of PDLSCs enhanced cell differentiation as determined by elevated RUNX-2 and ALP protein expression. In this context, the inflammatory stimulus impaired cell OCN protein expression, while dual stimuli led to decreased RUNX-2 and OCN mRNA levels. Although preconditioning PDLSCs with inflammatory and/or hypoxic pretreatments resulted in no differences in the production of matrix proteins, hypoxic pretreatment led to the generation of thicker cell sheets; the inflammatory stimulus weakened the ability of cells to form sheets. All the resultant cell sheets exhibited clear bone regeneration following ectopic transplantation as well as in periodontal defect models; the amount of new bone formed by hypoxia-preconditioned cells was significantly greater than that formed by inflammatory stimulus- or dual-stimuli-treated cells or by nonpreconditioned cells. The regeneration of new cementum and periodontal ligaments was only identified in the hypoxia-stimulus and no-stimulus cell groups. Our findings suggest that PDLSCs that undergo short-term hypoxic pretreatment show improved cellular behavior in vitro and enhanced regenerative potential in vivo. The preconditioning of PDLSCs via combined treatments or an inflammatory stimulus requires further investigation.
在本研究中，我们广泛筛选了短期炎症和/或低氧预处理后牙周膜干细胞（PDLSCs）的体外和体内效应。我们发现，对PDLSCs进行24小时低氧预处理可显著增强细胞迁移并改善细胞表面CXCR4表达。此外，低氧预处理的PDLSCs表现出更好的细胞集落形成和增殖能力。与未处理的细胞相比，双重刺激的细胞也形成了更多的集落，但它们的增殖并未增加。重要的是，通过升高的RUNX-2和碱性磷酸酶（ALP）蛋白表达确定，PDLSCs的低氧预处理增强了细胞分化。在这种情况下，炎症刺激损害了细胞骨钙素（OCN）蛋白表达，而双重刺激导致RUNX-2和OCN mRNA水平降低。尽管用炎症和/或低氧预处理PDLSCs在基质蛋白产生方面没有差异，但低氧预处理导致形成更厚的细胞片；炎症刺激削弱了细胞形成细胞片的能力。所有产生的细胞片在异位移植以及牙周缺损模型中均表现出明显的骨再生；低氧预处理细胞形成的新骨量明显大于炎症刺激或双重刺激处理的细胞或未预处理细胞形成的新骨量。仅在低氧刺激和无刺激细胞组中发现了新牙骨质和牙周韧带的再生。我们的研究结果表明，经过短期低氧预处理的PDLSCs在体外表现出改善的细胞行为，在体内具有增强的再生潜力。通过联合治疗或炎症刺激对PDLSCs进行预处理需要进一步研究。
