Photobiomodulation Facilitates Rat Cutaneous Wound Healing by Promoting Epidermal Stem Cells and Hair Follicle Stem Cells Proliferation.

Abstract

Cutaneous wound healing represents a common fundamental phenomenon requiring the participation ofcells of distinct types and a major concern for the public. Evidence has confirmed that photobiomodulation (PBM) usingnear-infrared (NIR)can promote wound healing, but the cells involved and theprecise molecular mechanisms remain elusive. Full-thickness skin defects with a diameter of 1.0cm were made on the back of rats and randomly divided into the control group, 10J, 15J, and 30J groups. Thewound healing rate at days 4, 8, and 12 postoperativelywasmeasured.HE and Masson staining was conducted to revealthe histological characteristics. Immunofluorescence staining was performedto label the epidermal stem cells (ESCs) and hair follicle stem cells (HFSCs). Western blot was performed to detect the expressions ofproteins associated withESCs and HFSCs. Cutaneous wound tissues were collected for RNA sequencing. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes analysis was performed, and the hub geneswereidentified usingCytoHubba and validated by qRT-PCR. PBM can promote reepithelialization, extracellular matrix deposition, and wound healing, increase the number of KRT14+/PCNA+ ESCs and KRT15+/PCNA+ HFSCs, and upregulate the protein expression of P63, Krt14, and PCNA. Three hundred and sixty-six differentially expressed genes (DEGs) and 7hubgenes includingSox9, Krt5, Epcam, Cdh1, Cdh3, Dsp, and Pkp3were identified. These DEGs are enriched in skin development, cell junction, and cadherin binding involved in cell-cell adhesion etc., while these hub genes are related toskin derived stem cells and cell adhesion. PBM accelerates wound healing by enhancing reepithelialization through promoting ESCs and HFSCs proliferation and elevating the expression of genes associated with stem cells and cell adhesion. This may provide a valuable alternative strategy to promote wound healing and reepithelialization by modulating the proliferation ofskin derived stem cells and regulating genes related to cell adhesion.