Therapeutic potential of recombinant human collagen XVII in blue light-induced skin photoaging: preserving epidermal-dermal structural integrity and functional homeostasis

Background Excessive exposure to blue light (BL) contributes to skin photoaging by inducing oxidative stress, inflammation, extracellular matrix degradation, and disruption of epidermal-dermal integrity. Recombinant human type XVII collagen (rhCol17) is a bioactive material with high biocompatibility and reported roles in tissue repair. However, its protective effects against BL-induced photoaging remain unclear. Methods In vitro and in vivo photoaging models were established using human keratinocytes (HaCaTs), dermal fibroblasts (HDFs), and rat dorsal skin exposed to BL. The protective effects of rhCol17 were assessed by Cell Counting Kit-8 assays, quantitative real-time polymerase chain reaction, Western blot, cell migration assays, enzyme-linked immunosorbent assay, immunofluorescence, histopathology, ultrasound measurements, and transmission electron microscopy. Results In vitro , rhCol17 treatment enhanced BL-impaired HaCaT and HDF viability and migration, while reducing cellular senescence, reactive oxygen species accumulation, and pro-inflammatory cytokine production. In vivo , rhCol17 ameliorated BL-induced photoaging, as evidenced by reduced transepidermal water loss, normalization of epidermal and dermal thickness, preservation of collagen, mitigation of elastic fiber degeneration, and increased hemidesmosome density. Furthermore, rhCol17 restored the expression of key collagen and basement membrane components and attenuated MMPs upregulation both in vitro and in vivo . Mechanistically, rhCol17 modulated Notch signaling in HaCaTs, contributing to the prevention of cellular senescence. Conclusion These findings suggested that rhCol17 protects against BL-induced molecular damage and functional impairment in epidermal and dermal cells, while maintaining epidermal-dermal structural integrity. rhCol17 represents a promising therapeutic strategy for preventing BL-related skin damage and offers preliminary insights for potential clinical translation.