High-fluence Low-power Laser Irradiation Promotes Odontogenesis and Inflammation Resolution in Periodontitis by Enhancing Stem Cell Proliferation and Differentiation

Periodontitis can exert a severe impact on the life of patients, and the use of stem cell therapy for this disease is promising. The inflammatory response consequent to periodontitis can promote stem cell proliferation. Activated inflammation triggers inhibitory cytokine secretion, thus reducing inflammation subsequent to stem cell activation. High‑fluence low‑power laser irradiation (HF‑LPLI) has the ability to regulate stem cell function through its effect on inflammation. Thus, the aim of the present study was to examine whether HF‑LPLI is able to activate stem cells to promote regeneration in periodontitis by promoting inflammation resolution, as well as to evaluate the underlying mechanism of action if an effect is observed. Stem cells were treated with HF‑LPLI following inflammation activation. Reverse transcription‑quantitative polymerase chain reaction and EdU assay were used to evaluate cell proliferation and differentiation. Flow cytometry and immunofluorescence were also used to detect the ability of HF‑LPLI to regulate the surrounding inflammatory environment. Animal models of periodontal disease were treated with stem cells and HF‑LPLI, and regeneration was detected by hematoxylin and eosin staining and in vivo imaging. It was observed that HF‑LPLI promoted inflammation resolution by reducing the excessive inflammatory response, and finally stimulated stem cell proliferation and differentiation. Furthermore, in vivo results revealed that stem cells treated with HF‑LPLI induced bone regeneration. HF‑LPLI stimulated stem cell proliferation and differentiation by promoting inflammation resolution subsequent to stem cell activation, providing a new strategy for the clinical treatment of periodontitis.