Umbilical cord mesenchymal stem cells (UCMSCs) have been identified as a potentially ideal cell type for use in regenerative therapeutic contexts owing to their excellent paracrine secretory abilities and other desirable properties. Previous work has shown that stem cell-derived exosomes can effectively reduce skin aging, but few studies have specifically focused on the role of UCMSC-derived exosomes in this context. In this study, we isolated exosomes derived from UCMSCs grown in a three-dimensional culture system and explored their ability to modulate the photo-aging of HaCaT keratinocytes. Cell viability and proliferation were assessed using CCK8 assay, whereas wound healing and transwell assays were used to assess cell migratory capabilities. UVB irradiation (60 mJ/cm²) was used to induce photo-aging of HaCaT cells. TUNEL and SA-β-Gal staining were used to explore HaCaT cell apoptosis and senescence, respectively, whereas real-time quantitative PCR was used to assess the expression of relevant genes at the mRNA level. We found that UCMSC-derived exosomes were able to enhance normal HaCaT cell proliferation and migration while also inhibiting UVB-induced damage to these cells. These exosomes also reduced HaCaT cell apoptosis and senescence, increasing collagen type I expression and reducing matrix metalloproteinase (MMP1) expression in photo-aged HaCaT cells. Together, these findings indicate that UCMSC-derived exosomes have the potential to be used therapeutically to suppress skin aging.

中文翻译：

---

脐带间充质干细胞衍生的外泌体改善 HaCaT 细胞光老化

脐带间充质干细胞 (UCMSCs) 因其出色的旁分泌能力和其他理想特性，已被确定为用于再生治疗环境的潜在理想细胞类型。先前的工作表明，干细胞衍生的外泌体可以有效减少皮肤老化，但很少有研究专门关注 UCMSC 衍生的外泌体在这方面的作用。在这项研究中，我们分离了来自在三维培养系统中生长的 UCMSCs 的外泌体，并探索了它们调节 HaCaT 角质形成细胞光老化的能力。使用 CCK8 测定评估细胞活力和增殖，而使用伤口愈合和 transwell 测定来评估细胞迁移能力。UVB 照射（60 mJ/cm ²) 用于诱导 HaCaT 细胞的光老化。TUNEL 和 SA-β-Gal 染色分别用于探索 HaCaT 细胞凋亡和衰老，而实时定量 PCR 用于评估相关基因在 mRNA 水平的表达。我们发现 UCMSC 衍生的外泌体能够增强正常的 HaCaT 细胞增殖和迁移，同时还能抑制 UVB 对这些细胞的损伤。这些外泌体还减少了 HaCaT 细胞的凋亡和衰老，增加了 I 型胶原蛋白的表达并降低了光老化 HaCaT 细胞中基质金属蛋白酶 (MMP1) 的表达。总之，这些发现表明 UCMSC 衍生的外泌体有可能在治疗上用于抑制皮肤老化。