临床上关节软骨缺损的治疗效果仍不理想。直接细胞植入面临着致瘤性、免疫原性和不可控性等挑战。基于细胞外囊泡（EV）的无细胞疗法成为软骨再生的一种有前途的替代方法。尽管如此，来自不同细胞的电动汽车表现出不同的特征和效果。该研究的目的是发现细胞中的 EV 在软骨形成时间轴上对软骨再生的功能。这里，用骨髓间充质干细胞（BMSCs）-EVs、幼年软骨细胞-EVs和成体软骨细胞-EVs代表不同分化阶段的EVs，并加入成纤维细胞-EVs作为周围信号进行比较。成纤维细胞-EVs 对软骨形成的影响最差。虽然幼年软骨细胞-EV和成年软骨细胞-EV对软骨形成分化的影响与BMSC-EV相当，但BMSC-EV对细胞增殖和迁移的影响最好。此外，BMSCs分泌的EVs数量远多于软骨细胞。一种来自小肠粘膜下层 (SIS) 的可注射脱细胞外基质 (dECM) 水凝胶被制造为具有天然基质微环境的 EV 递送平台。在大鼠模型中，将负载 BMSCs-EVs 的 SIS 水凝胶注射到关节软骨缺损处，显着增强体内软骨再生。此外，蛋白质组学揭示BMSCs-EVs特异性上调多种代谢和生物合成过程，这可能是潜在的机制。因此，装载有 BMSCs-EV 的可注射 SIS 水凝胶可能是治疗关节软骨缺陷的一种有前途的治疗方法。© 作者 2024。

Articular cartilage defect therapy is still dissatisfactory in clinic. Direct cell implantation faces challenges, such as tumorigenicity, immunogenicity, and uncontrollability. Extracellular vesicles (EVs) based cell-free therapy becomes a promising alternative approach for cartilage regeneration. Even though, EVs from different cells exhibit heterogeneous characteristics and effects. The aim of the study was to discover the functions of EVs from the cells during chondrogenesis timeline on cartilage regeneration. Here, bone marrow mesenchymal stem cells (BMSCs)-EVs, juvenile chondrocytes-EVs, and adult chondrocytes-EVs were used to represent the EVs at different differentiation stages, and fibroblast-EVs as surrounding signals were also joined to compare. Fibroblasts-EVs showed the worst effect on chondrogenesis. While juvenile chondrocyte-EVs and adult chondrocyte-EVs showed comparable effect on chondrogenic differentiation as BMSCs-EVs, BMSCs-EVs showed the best effect on cell proliferation and migration. Moreover, the amount of EVs secreted from BMSCs were much more than that from chondrocytes. An injectable decellularized extracellular matrix (dECM) hydrogel from small intestinal submucosa (SIS) was fabricated as the EVs delivery platform with natural matrix microenvironment. In a rat model, BMSCs-EVs loaded SIS hydrogel was injected into the articular cartilage defects and significantly enhanced cartilage regeneration in vivo. Furthermore, protein proteomics revealed BMSCs-EVs specifically upregulated multiple metabolic and biosynthetic processes, which might be the potential mechanism. Thus, injectable SIS hydrogel loaded with BMSCs-EVs might be a promising therapeutic way for articular cartilage defect.© The Author(s) 2024.