Abstract Objective Stem cells hold promise for treating hair loss. Here an in vitro mouse model was developed using outer root sheaths (ORSs) isolated from hair follicles for studying stem cell-mediated dermal papillary regeneration. Methods Under sterile conditions, structurally intact ORSs were isolated from hair follicles of 3-day-old Kunming mice and incubated in growth medium. Samples were collected daily for 5 days. Stem cell distribution, proliferation, differentiation, and migration were monitored during regeneration. Results Cell proliferation began at the glass membrane periphery then spread gradually toward the membrane center, with the presence of CD34 and CD200 positive stem cells involved in repair initiation. Next, CD34 positive stem cells migrated down the glass membrane, where some participated in ORS formation, while other CD34 cells and CD200 positive cells migrated to hair follicle centers. Within the hair follicle matrix, stem cells divided, grew, differentiated and caused outward expansion of the glass membrane to form a dermal papillary structure containing alpha-smooth muscle actin. Neutrophils attracted to the wound site phagocytosed bacterial and cell debris to protect regenerating tissue from infection. Conclusion Isolated hair follicle ORSs can regenerate new dermal papillary structures in vitro. Stem cells and neutrophils play important roles in the regeneration process.

中文翻译：

---

用于研究干细胞对毛囊外根鞘再生影响的小鼠模型

摘要 目的干细胞有望治疗脱发。在这里，使用从毛囊中分离的外根鞘 (ORS) 开发了一种体外小鼠模型，用于研究干细胞介导的真皮乳头再生。方法 在无菌条件下，从 3 日龄昆明小鼠的毛囊中分离结构完整的 ORS，并在生长培养基中培养。每天收集样品，持续 5 天。在再生过程中监测干细胞分布、增殖、分化和迁移。结果细胞增殖开始于玻璃膜外围，然后逐渐向膜中心扩散，CD34和CD200阳性干细胞参与修复启动。接下来，CD34 阳性干细胞沿着玻璃膜向下迁移，其中一些参与了 ORS 的形成，而其他 CD34 细胞和 CD200 阳性细胞迁移到毛囊中心。在毛囊基质内，干细胞分裂、生长、分化并导致玻璃膜向外扩张，形成含有α-平滑肌肌动蛋白的真皮乳头状结构。被吸引到伤口部位的嗜中性粒细胞吞噬细菌和细胞碎片，以保护再生组织免受感染。结论分离的毛囊ORSs可以在体外再生新的真皮乳头状结构。干细胞和中性粒细胞在再生过程中起着重要作用。被伤口部位吸引的中性粒细胞吞噬细菌和细胞碎片，以保护再生组织免受感染。结论分离的毛囊ORSs可以在体外再生新的真皮乳头状结构。干细胞和中性粒细胞在再生过程中起着重要作用。被伤口部位吸引的中性粒细胞吞噬细菌和细胞碎片，以保护再生组织免受感染。结论分离的毛囊ORSs可以在体外再生新的真皮乳头状结构。干细胞和中性粒细胞在再生过程中起着重要作用。