Major histocompatibility complex class I immunofluorescence staining. Yellow boxes and arrows highlight major histocompatibility complex class I (MHC-I) antibody expressed on the cytomembrane. Within the 21 days, almost no significant difference was detected in the expression of MHC-I antibodies in the three groups. (a), (b), (d), (e) There were a few red dots within the first 14 days in Groups A and B. (c), (f), (i) Postoperative at 21 days, there was no visible MHC-I expression in all cells migrating into the scaffold in Group C. Scale bars: 50 μm. Gel-C6S-HA, gelatin–chondroitin-6-sulfate–hyaluronic acid; HFSC, hair follicle stem cell; VEGF, vascular endothelial growth factor.