Low-level laser treatment promotes skin wound healing by activating hair follicle stem cells in female mice.

The aim of the study was to explore the effect and mechanism of a low-level laser on hair follicle stem cells in full-thickness skin wound healing in mice. Full-thickness skin defects were generated by a 5-mm punch biopsy tool on the backs of depilated C57/BL6N mice, which were randomly divided thereafter into a low-dose laser treatment group (LLLT-Low), a high-dose laser treatment group (LLLT-High), and a control group (control). From the day of modeling to the day before the skin samples were taken, the wound area and wound edge of the mice in the LLLT-Low and LLLT-High groups were irradiated with a laser comb every 24 h, and the energy density was 1 J/cm2 and 10 J/cm2, respectively. The control group was irradiated with an ordinary fluorescent lamp. At 0, 3, 5, 10, and 14 days after modeling, pictures of each wound were taken, and the percent wound closure was analyzed. At 3, 5, 10, and 14 days after modeling, the samples were observed by hematoxylin and eosin (HE) and immunofluorescence (IF) staining. Whole transcriptome sequencing (RNA-Seq) was performed on the samples on day 10. Gene Ontology (GO) analysis was performed, and the results were validated by Western blot analysis and enzyme-linked immunosorbent assay (ELISA). The analysis of the percent of wound closure showed that healing was accelerated (significantly from 5 to 10 days) in the LLLT-Low group, but there was no clear change in the LLLT-High group. HE staining showed that the LLLT-Low group had an increasing number of hair follicles and a tendency to migrate to the center of the wound. There was no significant increase in the number of hair follicles and no obvious migration in the LLLT-High group. Immunofluorescence staining showed that the total number of CK15 + hair follicle stem cells in the LLLT-Low group was higher than that in the control group and LLLT-High group at all time points. The number and farthest migration distance of CK15 + hair follicle stem cells increased significantly with time, and after 5 days, they were significantly higher than those in the control group and LLLT-High group. RNA-Seq and Western blot analysis showed that the expression of related genes in hair follicle stem cells, including CK15, in the LLLT-Low group was upregulated. GO analysis and ELISA showed that the expression of many cytokines, represented by IL34, in the LLLT-Low group was upregulated. Low-level laser treatment can promote the proliferation, differentiation, and migration of CK15 + hair follicle stem cells by upregulating the cytokine IL34, thereby promoting skin wound healing in mice.

Comparison of low-level laser treatment and extracorporeal shock wave therapy in subacromial impingement syndrome: a randomized, prospective clinical study.

The aim of this study was to compare the efficacy of low-level laser treatment (LLLT) and extracorporeal shock wave therapy (ESWT) in the treatment of subacromial impingement syndrome (SIS). Seventy-one patients with subacromial impingement were randomly assigned to LLLT (n = 37) and ESWT (n = 34) groups. The patients received a total of 15 sessions of LLLT or once a week for 3 sessions of ESWT. All patients, before treatment, at the end of treatment, and 3 months after treatment, were evaluated with range of motion (ROM), visual analogue pain scale (VAS pain), Shoulder Pain and Disability Index (SPADI), Beck Depression and Anxiety Inventories, the Short Form Health Survey (SF-36), and Pittsburgh Sleep Quality Index (PSQI). In both groups, there was a significant improvement in all outcome measures (p < 0.05) except the mental health score in the LLLT group. ESWT group showed more improvements in terms of SPADI disability and total scores, PSQI, and physical-mental health scores at the end of treatment (p < 0.05). The improvement in VAS pain day and SPADI scores at the third month was significantly more evident in the ESWT group (p < 0.05). Both LLLT and ESWT treatments are effective in the treatment of SIS in the short-medium term and can be used in clinical practice. Future larger prospective clinical trials are needed to investigate the long-term efficacy and optimal treatment protocol of LLLT and ESWT in SIS.

Low-level laser treatment stimulates hair growth via upregulating Wnt10b and ß-catenin expression in C3H/HeJ mice.

This study was conducted in order to evaluate the role of low-level laser treatment (LLLT) in hair growth in C3H/HeJ mice. Healthy C57BL/6 mice were randomly divided into two groups: with and without low-level laser treatment. The skin color of each mouse was observed each day. Skin samples were collected for H&E, immunofluorescence, PCR, and western blot analysis, to observe the morphology of hair follicles and detect the expression levels of Wnt10b and ß-catenin. Observation of skin color demonstrated that black pigmentation started significantly earlier in the laser group than in the control group. Hair follicle number in both groups showed no difference; however, the hair follicle length presented a significant difference. Wnt10b protein was detected on the second day in hair matrix cells in the LLLT group but not in the control group. PCR and western blot results both illustrated that expression of Wnt10b and ß-catenin was significantly higher in the LLLT group than in the control group. Our study illustrated that low-level laser treatment can promote hair regrowth by inducing anagen phase of hair follicles via initiating the Wnt10b/ß-catenin pathway.

Current indications for low level laser treatment in maxillofacial surgery: a review.

Low level laser treatment (LLLT) is currently being used for various disorders, but with no convincing scientific evidence. Most recently we have noticed an increase in published randomised controlled trials (RCTs) that have focused on its applications in wound healing, scarring, disorders of the temporomandibular joint (TMJ), oral mucositis, and dental pain. Our aim therefore was to assess the scientific evidence about its current efficacy in maxillofacial surgery. We reviewed PubMed from January 2003 to January 2013 using the key phrase "low level laser treatment". Our inclusion criterion was intervention studies in humans of more than 10 patients. We excluded animal studies and papers in languages other than English, French, and German. We found 45 papers that we screened independently. The resulting full texts were scrutinised by two authors who awarded a maximum of 5 points using the Jadad scale for assessing the quality of RCT, and extracted the data according to sample size, variables of LLLT, the authors' conclusions, and the significance of the result. LLLT seems to be effective for the treatment of oral mucositis after treatment for head and neck cancer. However, it cannot yet be considered a valid treatment for disorders of the TMJ. It seems to improve gingival healing, and myofacial and dental pain.