METHODS: CCs were directly cocultured with SDSCs in pellet or indirectly cocultured using a conditioned medium in vitro for 3 weeks. Cartilage matrix formation and hypertrophic differentiation of CCs were analyzed by RT-PCR, biochemical assays, and histological staining. Cocultured pellets were implanted into the osteochondral defects made on the femoral groove of the rats. Then, macroscopic and histological evaluations were performed.
RESULTS: Pellets formed by CCs alone and CCs cocultured with SDSCs reveal equal cartilage matrix deposition. However, the gene expression of type X collagen was significantly downregulated in cocultured pellets. Immunohistochemistry analysis revealed suppressed expression of type X collagen in cocultured pellets, indicating SDSCs may suppress hypertrophic differentiation of chondrocytes. Further in indirect coculture experiment, SDSCs suppressed type X collagen expression as well and promoted the proliferation of CCs, indicating SDSCs may influence CCs by paracrine mechanism. The pellets implanted in the osteochondral defects showed good restoration effects, whereas the grafts constructed with CCs and SDSCs showed lower type X expression levels.
CONCLUSIONS: These results suggest that SDSCs may maintain the phenotype of CCs and prevent the hypertrophic differentiation of CCs in cartilage repair.The Translational Potential of this Article: CCs is a promising donor cell source for cell-based therapy for cartilage repair. Based on our study, cocultured with SDSCs weakened the tendency of hypertrophy and calcification of CCs, which provide a potential usage of SDSCs in CCs-based cartilage repair therapy to suppress newly formed cartilage calcification and improve clinical outcomes.
方法:将CC与SDSC直接共培养在沉淀中或使用条件培养基在体外间接共培养3周。通过RT-PCR分析CCs的软骨基质形成和肥大分化,生化化验,和组织学染色。将共晶颗粒植入大鼠股骨沟形成的骨软骨缺损中。然后,进行宏观和组织学评估.
结果:由单独的CC和与SDSC共培养的CC形成的颗粒显示出相等的软骨基质沉积。然而,共培养颗粒中X型胶原基因表达显著下调。免疫组织化学分析显示共培养的颗粒中X型胶原的表达受到抑制,提示SDSCs可抑制软骨细胞的肥大分化。在间接共培养实验中,SDSCs同时抑制X型胶原的表达,促进CCs的增殖,提示SDSC可能通过旁分泌机制影响CC。骨小丸植入骨软骨缺损显示良好的修复效果,而用CC和SDSC构建的移植物显示较低的X型表达水平。
结论:这些结果表明,SDSCs可以维持CCs的表型,防止CCs在软骨修复中的肥大分化。本文的转化潜力:CCs是用于软骨修复的基于细胞的疗法的有前途的供体细胞来源。根据我们的研究,与SDSCs共培养削弱了CCs肥大和钙化的趋势,这提供了SDSCs在基于CCs的软骨修复治疗中的潜在用途,以抑制新形成的软骨钙化并改善临床结果。