Stem cell-based therapies have been shown to have considerable potential for improving wound healing. Accumulating evidence indicates that stem cells promote tissue repair by secreting paracrine signals that improve responses to injury by resident skin cells. Human gingival derived mesenchymal stem cell-like populations (GMSC) are post-natal stem cells that express surface markers associated with MSC. GMSC have also been shown to exhibit multi-differentiation capacity and immunomodulatory properties. This study aimed to examine the effects of human GMSC secretome on acute wound healing using in vitro and in vivo models.
The effect of GMSC secretome on the capacity of keratinocytes and fibroblasts to migrate and proliferate was determined in vitro using scratch wound closure and WST1 assay, respectively. Additionally, two excisional wounds were created on the dorsal surface of mice (n=8/group) and 100µL of 20X GMSC secretome were intradermally injected to the wound margins. The wounds were imaged daily until day 14, for macroscopic wound area determination. Wound tissues were collected at 3, 7, and 14 days post-wounding and were stained with H&E staining to microscopic analysis of wound. Immunohistochemistry staining of tissues was performed to investigate the inflammation and collagen deposition in wound area.
Cells treated with GMSC secretome showed improved rate of scratch closure and increased cellular proliferation compared to controls. Wounds intradermally injected with GMSC secretome showed a significant reduction in macroscopic wound area compared with controls. Microscopic analysis of wound tissues showed significant decrease in dermal wound width and increased rate of reepithelialisation. Collagen deposition was increased and a decrease in inflammatory cell infiltration was observed in HGF-CM treated wounds.
These findings demonstrate a therapeutic effect of GMSC secretome therapy on wound healing in vitro and in vivo. Clinical application of GMSC secretome may be a potential option for cell-free therapy to accelerate full-thickness skin wound healing.