Biomaterials and Tissue Engineering Group, Leeds Dental Institute, University of Leeds, UK.
J Tissue Eng Regen Med. 2013 Jun;7(6):461-9. doi: 10.1002/term.544. Epub 2012 Mar 7.
Non-invasive monitoring of living cells in vivo provides an important tool in the development of cell-based therapies in cartilage tissue engineering. High-resolution magnetic resonance imaging (MRI) has been used to monitor target cell populations in vivo. However, the side-effects on cell function of the labelling reagents, such as superparamagnetic iron oxide (SPIO), are still unclear. This study investigated the effect of SPIO particles on the chondrogenic differentiation of human bone marrow stromal cells (HBMSCs), neonatal and adult chondrocytes in vitro. Cells were labelled with SPIO for 24 h and chondrogenesis induced in serum-free medium including TGFβ3. For labelled/unlabelled cells, viability, morphology and proliferation were determined using CellTracker™ Green and PicoGreen dsDNA assays. The expression of SOX9, COL2A1 and ACAN was investigated using qRT-PCR after 2, 7 and 14 days. The results showed that viability was unaffected in all of the cells but cell morphology changed towards a 'stretched' phenotype following SPIO uptake. Cell proliferation was reduced only for labelled neonatal chondrocytes. SOX9 and COL2A1 expression decreased at day 2 but not at days 7 and 14 for labelled HBMSCs and adult chondrocytes; ACAN expression was unaffected. In contrast, SOX9 and COL2A1 expression were unaffected in labelled neonatal chondrocytes but a decrease in ACAN expression was seen at day 14. The results suggest that downregulation of chondrogenic genes associated with SPIO labelling is temporary and target cell-dependent. Resovist® can be used to label HBMSCs or mature chondrocytes for MR imaging of cells for cartilage tissue engineering.
在软骨组织工程中，对活细胞进行非侵入性监测为基于细胞的治疗方法的发展提供了重要工具。高分辨率磁共振成像（MRI）已被用于监测体内的靶细胞群体。然而，标记试剂（如超顺磁氧化铁（SPIO））对细胞功能的副作用尚不清楚。本研究调查了 SPIO 颗粒对体外人骨髓基质细胞（HBMSCs）、新生儿和成年软骨细胞的软骨分化的影响。细胞用 SPIO 标记 24 小时，并在包含 TGFβ3 的无血清培养基中诱导软骨生成。对于标记/未标记的细胞，使用 CellTracker™ Green 和 PicoGreen dsDNA 测定法测定细胞活力、形态和增殖。使用 qRT-PCR 在第 2、7 和 14 天检测 SOX9、COL2A1 和 ACAN 的表达。结果表明，所有细胞的活力均未受影响，但 SPIO 摄取后细胞形态向“伸展”表型改变。仅标记的新生儿软骨细胞的细胞增殖减少。标记的 HBMSCs 和成年软骨细胞的 SOX9 和 COL2A1 表达在第 2 天下降，但在第 7 和 14 天没有下降；ACAN 表达不受影响。相比之下，标记的新生儿软骨细胞的 SOX9 和 COL2A1 表达不受影响，但在第 14 天观察到 ACAN 表达下降。结果表明，与 SPIO 标记相关的软骨生成基因的下调是暂时的且与靶细胞有关。Resovist®可用于标记 HBMSCs 或成熟软骨细胞，以进行软骨组织工程中细胞的 MRI 成像。
