Kim Myung-Seo, Chung Hyun-Ju, Kim Kang-Il
Department of Orthopaedic Surgery, School of Medicine, Kyung Hee University and Kyung Hee University Hospital at Gangdong, Seoul 05278, South Korea.
Department of Core Research Laboratory, Clinical Research Institute, Kyung Hee University Hospital at Gangdong, Seoul 05278, South Korea.
World J Stem Cells. 2022 Dec 26;14(12):839-850. doi: 10.4252/wjsc.v14.i12.839.
There is still no consensus on which concentration of mesenchymal stem cells (MSCs) to use for promoting fracture healing in a rat model of long bone fracture.
To assess the optimal concentration of MSCs for promoting fracture healing in a rat model.
Wistar rats were divided into four groups according to MSC concentrations: Normal saline (C), 2.5 × 10 (L), 5.0 × 10 (M), and 10.0 × 10 (H) groups. The MSCs were injected directly into the fracture site. The rats were sacrificed at 2 and 6 wk post-fracture. New bone formation [bone volume (BV) and percentage BV (PBV)] was evaluated using micro-computed tomography (CT). Histological analysis was performed to evaluate fracture healing score. The protein expression of factors related to MSC migration [stromal cell-derived factor 1 (SDF-1), transforming growth factor-beta 1 (TGF-β1)] and angiogenesis [vascular endothelial growth factor (VEGF)] was evaluated using western blot analysis. The expression of cytokines associated with osteogenesis [bone morphogenetic protein-2 (BMP-2), TGF-β1 and VEGF] was evaluated using real-time polymerase chain reaction.
Micro-CT showed that BV and PBV was significantly increased in groups M and H compared to that in group C at 6 wk post-fracture ( = 0.040, = 0.009; = 0.004, = 0.001, respectively). Significantly more cartilaginous tissue and immature bone were formed in groups M and H than in group C at 2 and 6 wk post-fracture ( = 0.018, = 0.010; = 0.032, = 0.050, respectively). At 2 wk post-fracture, SDF-1, TGF-β1 and VEGF expression were significantly higher in groups M and H than in group L ( = 0.031, = 0.014; < 0.001, < 0.001; = 0.025, < 0.001, respectively). BMP-2 and VEGF expression were significantly higher in groups M and H than in group C at 6 wk post-fracture ( = 0.037, = 0.038; = 0.021, = 0.010). Compared to group L, TGF-β1 expression was significantly higher in groups H ( = 0.016). There were no significant differences in expression levels of chemokines related to MSC migration, angiogenesis and cytokines associated with osteogenesis between M and H groups at 2 and 6 wk post-fracture.
The administration of at least 5.0 × 10 MSCs was optimal to promote fracture healing in a rat model of long bone fractures.
在长骨骨折大鼠模型中，对于使用何种浓度的间充质干细胞（MSC）来促进骨折愈合仍未达成共识。
评估在大鼠模型中促进骨折愈合的MSC最佳浓度。
将Wistar大鼠根据MSC浓度分为四组：生理盐水（C）组、2.5×10（低剂量，L）组、5.0×10（中剂量，M）组和10.0×10（高剂量，H）组。将MSC直接注射到骨折部位。在骨折后2周和6周处死大鼠。使用微型计算机断层扫描（CT）评估新骨形成[骨体积（BV）和BV百分比（PBV）]。进行组织学分析以评估骨折愈合评分。使用蛋白质印迹分析评估与MSC迁移相关的因子[基质细胞衍生因子1（SDF-1）、转化生长因子-β1（TGF-β1）]和血管生成相关因子[血管内皮生长因子（VEGF）]的蛋白表达。使用实时聚合酶链反应评估与成骨相关的细胞因子[骨形态发生蛋白-2（BMP-2）、TGF-β1和VEGF]的表达。
微型CT显示，骨折后6周，M组和H组的BV和PBV与C组相比显著增加（分别为P = 0.040，P = 0.009；P = 0.004，P = 0.001）。骨折后2周和6周，M组和H组形成的软骨组织和未成熟骨明显多于C组（分别为P = 0.018，P = 0.010；P = 0.032，P = 0.050）。骨折后2周，M组和H组的SDF-1、TGF-β1和VEGF表达显著高于L组（分别为P = 0.031，P = 0.014；P < 0.001，P < 0.001；P = 0.025，P < 0.001）。骨折后6周，M组和H组的BMP-2和VEGF表达显著高于C组（分别为P = 0.037，P = 0.038；P = 0.021，P = 0.010）。与L组相比，H组的TGF-β1表达显著更高（P = 0.016）。骨折后2周和6周，M组和H组之间与MSC迁移、血管生成相关的趋化因子以及与成骨相关的细胞因子的表达水平无显著差异。
在长骨骨折大鼠模型中，至少给予5.0×10的MSC是促进骨折愈合的最佳选择。
