Background and objectives: The objective of this study was to investigate whether conditioned medium from photobiomodulation (PBM) irradiated adipose-derived stromal cell (ASC) spheroids prior to implanting could stimulate angiogenesis and tissue regeneration to improve functional recovery of skin tissue in an animal skin wound model.
Methods and results: ASC were split and seeded on chitosan-coated 24 well plate at a density of 7.5×104 cells/cm2, and allowed to adhere at 37°C. Within 3 days of culture, ASC formed spheroids by PBM irradiation. Conditioned medium (CM) fractions were collected from the PBM-ASC to yield nor adipose-derived stromal cell spheroid (spheroid) and PBM-spheroid, respectively, centrifuged at 13,000 g at 4℃ for 10 min, and stored prior to use for ELISA, protein assay, or in vivo wound-healing assays. Phosphate-buffered saline, cultured CM from ASCs, PBM irradiation prior to implanting conditioned medium from ASC, cultured CM from ASC spheroid, and PBM-spheroid-CM (PSC) were transplanted into a wound bed in athymic mice to evaluate therapeutic effects of PSC in vivo. PSC enhanced wound closure in a skin injury model compared to PBS, CM, PBM-CM, and spheroid-CM. The density of vascular formations increased as a result of angiogenic factors released by the wound bed and enhanced tissue regeneration at the lesion site.
Conclusions: These results indicate that implant of PSC can significantly improve functional recovery compared to PBS, CM, PBM-CM, or spheroid-CM treatment. Implant of PSC may be an effective form of paracrine mediated therapy for treating a wound bed.
Keywords: Adipose-derived stromal cell; Angiogenesis; Conditioned medium; Photobiomodulation; Spheroid; Wound healing.