Background: Transplantation of stem cells/scaffold is an efficient approach for treating tissue injury including full-thickness skin defects. However, the application of stem cells is limited by preservation issues, ethical restriction, low viability, and immune rejection in vivo. The mesenchymal stem cell conditioned medium is abundant in bioactive functional factors, making it a viable alternative to living cells in regeneration medicine. Methods: Nasal mucosa-derived ecto-mesenchymal stem cells (EMSCs) of rats were identified and grown in suspension sphere-forming 3D culture. The EMSCs-conditioned medium (EMSCs-CM) was collected, lyophilized, and analyzed for its bioactive components. Next, fibrinogen and chitosan were further mixed and cross-linked with the lyophilized powder to obtain functional skin patches. Their capacity to gradually release bioactive substances and biocompatibility with epidermal cells were assessed in vitro. Finally, a full-thickness skin defect model was established to evaluate the therapeutic efficacy of the skin patch. Results: The EMSCs-CM contains abundant bioactive proteins including VEGF, KGF, EGF, bFGF, SHH, IL-10, and fibronectin. The bioactive functional composite skin patch containing EMSCs-CM lyophilized powder showed the network-like microstructure could continuously release the bioactive proteins, and possessed ideal biocompatibility with rat epidermal cells in vitro. Transplantation of the composite skin patch could expedite the healing of the full-thickness skin defect by promoting endogenous epidermal stem cell proliferation and skin appendage regeneration in rats. Conclusion: In summary, the bioactive functional composite skin patch containing EMSCs-CM lyophilized powder can effectively accelerate skin repair, which has promising application prospects in the treatment of skin defects.

中文翻译：

---

负载 EMSC 多细胞球生物活性功能因子的复合皮肤贴片对大鼠全层皮肤缺损再生的评价

背景：干细胞/支架移植是治疗组织损伤（包括全层皮肤缺损）的有效方法。然而，干细胞的应用受到保存问题、伦理限制、低活力和体内免疫排斥等问题的限制。间充质干细胞条件培养基富含生物活性功能因子，使其成为再生医学中活细胞的可行替代品。方法：鉴定大鼠鼻粘膜来源的外胚层间充质干细胞 (EMSC)，并在悬浮球形成 3D 培养物中生长。收集、冻干 EMSC 条件培养基 (EMSC-CM)，并分析其生物活性成分。接下来，将纤维蛋白原和壳聚糖进一步混合并与冻干粉末交联以获得功能性皮肤贴剂。在体外评估了它们逐渐释放生物活性物质的能力以及与表皮细胞的生物相容性。最后，建立全层皮肤缺损模型来评估皮肤补片的治疗效果。结果：EMSCs-CM含有丰富的生物活性蛋白，包括VEGF、KGF、EGF、bFGF、SHH、IL-10和纤连蛋白。含有EMSCs-CM冻干粉的生物活性功能复合皮肤贴剂表现出网状微结构，可以持续释放生物活性蛋白，并且在体外与大鼠表皮细胞具有理想的生物相容性。移植复合皮肤补片可以通过促进大鼠内源性表皮干细胞增殖和皮肤附属器再生来加速全层皮肤缺损的愈合。结论：综上所述，含有EMSCs-CM冻干粉的生物活性功能复合皮肤贴剂能够有效加速皮肤修复，在皮肤缺损的治疗中具有广阔的应用前景。