BACKGROUND Meniscal injury repair with tissue engineering technique is promising. Among various scaffolds, the thermosensitive injectable hydrogel has recently attracted much attention. PURPOSE (1) Evaluate the biocompatibility of thermosensitive, injectable, in situ crosslinked hydrogel and (2) determine whether the hydrogel with or without transforming growth factor β1 (TGF-β1) could support the fibrochondrogenic differentiation of bone mesenchymal stromal cells (BMSCs) and promote the repair of a critical-sized defect in rabbit meniscus. STUDY DESIGN Controlled laboratory study. METHODS The rheological and sustained release properties of the hydrogel were demonstrated. BMSCs were isolated and cultured. Cell viability, quantitative polymerase chain reaction (qPCR), and Western blot were tested in vitro. In vivo, a critical-sized defect was introduced into the meniscus of 30 rabbits. Each defect was randomly assigned to be implanted with either phosphate-buffered saline (PBS); BMSC-laden hydrogel; or BMSC-laden, TGF-β1-incorporated hydrogel. Histological and immunohistochemical analyses were performed at 8 weeks after surgery. The Ishida scoring system was adopted to evaluate the healing quantitatively. RESULTS The elastic modulus of the hydrogel was about 1000 Pa. The hydrogel demonstrated a sustained-release property and could promote proliferation and induce fibrochondrogenic differentiation of BMSCs after the incorporation of TGF-β1 (P < .001). At 8 weeks after surgery, a large amount of fibrocartilaginous tissue, which was positive on safranin-O staining and expressed strong type II collagen intermingled with weak type I collagen, was observed in the defect region of the BMSC-laden, TGF-β1-incorporated hydrogel group. In the BMSC-laden hydrogel group, the defect was filled with fibrous tissue together with a small amount of fibrocartilage. The mean ± SD quantitative scores obtained for the 3 groups-PBS; BMSC-laden hydrogel; and BMSC-laden, TGF-β1-incorporated hydrogel-were 1.00, 3.20 ± 0.84, and 5.00 ± 0.71, respectively (P < .001). CONCLUSION The hydrogel was biocompatible and could stimulate strong fibrochondrogenic differentiation of BMSCs after the incorporation of TGF-β1. The local administration of the BMSC-laden, TGF-β1-incorporated hydrogel could promote the healing of rabbit meniscal injury. CLINICAL RELEVANCE This hydrogel is an alternative scaffold for meniscus tissue engineering.

中文翻译：

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通过使用热敏感的，可注射的，原位交联的水凝胶与包埋的骨间质基质细胞和转化生长因子β1，在兔模型中修复半月板缺损。

背景技术用组织工程技术修复半月板损伤是有希望的。在各种支架中，热敏可注射水凝胶最近引起了很多关注。目的（1）评估热敏性，可注射的原位交联水凝胶的生物相容性，以及（2）确定具有或不具有转化生长因子β1（TGF-β1）的水凝胶是否可以支持骨间充质基质细胞（BMSCs）的纤维软骨原性分化。促进兔半月板临界尺寸缺损的修复。研究设计受控的实验室研究。方法证明了水凝胶的流变和持续释放特性。分离并培养BMSC。体外测试了细胞活力，定量聚合酶链反应（qPCR）和蛋白质印迹。体内，将临界大小的缺陷引入到30只兔子的半月板中。每个缺损被随机分配植入磷酸盐缓冲盐水（PBS）中。载有BMSC的水凝胶; 或含有BMSC的TGF-β1结合水凝胶。术后8周进行组织学和免疫组化分析。采用石田评分系统定量评估愈合情况。结果水凝胶的弹性模量约为1000 Pa。水凝胶表现出持续释放的特性，并能在掺入TGF-β1后促进BMSCs的增殖并诱导其成纤维细胞分化（P <.001）。术后8周，大量的纤维软骨组织在番红O染色中呈阳性，并表达强II型胶原和弱I型胶原，在载有BMSC的TGF-β1结合的水凝胶组的缺损区域中观察到。在充满BMSC的水凝胶组中，缺损充满了纤维组织以及少量的纤维软骨。3组-PBS的平均值±SD定量得分；载有BMSC的水凝胶; 载有BMSC和掺有TGF-β1的水凝胶分别为1.00、3.20±0.84和5.00±0.71（P <0.001）。结论水凝胶具有生物相容性，并能在TGF-β1掺入后刺激骨髓间充质干细胞强烈的线粒体分化。局部施用含BMSC，TGF-β1的水凝胶可促进兔半月板损伤的愈合。临床相关性该水凝胶是半月板组织工程的替代支架。在充满BMSC的水凝胶组中，缺损充满了纤维组织以及少量的纤维软骨。3组-PBS的平均值±SD定量得分；载有BMSC的水凝胶; 载有TMSC-β1的BMSC和载有BMSC的水凝胶分别为1.00、3.20±0.84和5.00±0.71（P <.001）。结论水凝胶具有生物相容性，并能在TGF-β1掺入后刺激骨髓间充质干细胞强烈的线粒体分化。局部施用含BMSC，TGF-β1的水凝胶可促进兔半月板损伤的愈合。临床相关性该水凝胶是半月板组织工程的替代支架。在充满BMSC的水凝胶组中，缺损充满了纤维组织以及少量的纤维软骨。3组-PBS的平均值±SD定量得分；载有BMSC的水凝胶; 载有TMSC-β1的BMSC和载有BMSC的水凝胶分别为1.00、3.20±0.84和5.00±0.71（P <.001）。结论水凝胶具有生物相容性，并能在TGF-β1掺入后刺激骨髓间充质干细胞强烈的线粒体分化。局部施用含BMSC，TGF-β1的水凝胶可促进兔半月板损伤的愈合。临床相关性该水凝胶是半月板组织工程的替代支架。3组-PBS的平均值±SD定量得分；载有BMSC的水凝胶; 载有TMSC-β1的BMSC和载有BMSC的水凝胶分别为1.00、3.20±0.84和5.00±0.71（P <.001）。结论水凝胶具有生物相容性，并能在TGF-β1掺入后刺激BMSCs的强烈的线粒体分化。局部施用含BMSC，TGF-β1的水凝胶可促进兔半月板损伤的愈合。临床相关性该水凝胶是半月板组织工程的替代支架。3组-PBS的平均值±SD定量得分；载有BMSC的水凝胶; 载有BMSC和掺有TGF-β1的水凝胶分别为1.00、3.20±0.84和5.00±0.71（P <0.001）。结论水凝胶具有生物相容性，并能在TGF-β1掺入后刺激BMSCs的强烈的线粒体分化。局部施用含BMSC，TGF-β1的水凝胶可促进兔半月板损伤的愈合。临床相关性该水凝胶是半月板组织工程的替代支架。结论水凝胶具有生物相容性，并能在TGF-β1掺入后刺激BMSCs的强烈的线粒体分化。局部施用含BMSC，TGF-β1的水凝胶可促进兔半月板损伤的愈合。临床相关性该水凝胶是半月板组织工程的替代支架。结论水凝胶具有生物相容性，并能在TGF-β1掺入后刺激骨髓间充质干细胞强烈的线粒体分化。局部施用含BMSC，TGF-β1的水凝胶可促进兔半月板损伤的愈合。临床相关性该水凝胶是半月板组织工程的替代支架。