Photobiomodulation, Photomedicine, and Laser Surgery Volume XX, Number XX, 2020 ª Mary Ann Liebert, Inc. Pp. 1–6 DOI: 10.1089/photob.2019.4729
Biphasic Dose/Response of Photobiomodulation Therapy on Culture of Human Fibroblasts
Genoveva Lourdes Flores Luna, PhD,1 Ana Laura Martins de Andrade, PhD,2 Patricia Brassolatti, PhD,3 Paulo Se´ rgio Bossini, PhD,4 Fernanda de Freitas Anibal, PhD,3 Nivaldo Antonio Parizotto, PhD,2 and Aˆ ngela Merice de Oliveira Leal, PhD1
Objective: The objective of this study was to evaluate the effects of application of different fluences and energies of laser in the 24-, 48-, and 72-h periods in fibroblasts originating from human skin (HFF-1).
Methods: The cell used as a template for cell proliferation was HFF-1. For the photobiomodulation (PBM) application, a 660 nm laser with a power of 40 mW and energies of 0.84, 1.40, 5.88, and 6.72 J was used. Five experimental groups were studied: one control group (CG) with simulated PBM and four groups that received PBM in different doses. The changes observed after laser irradiation were evaluated by cell viability (trypan blue) and proliferation [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)] tests. Intergroup comparisons were performed using two-way analysis of variance and the Tukey post hoc test (software GraphPad Prism 7.0).
Results: In the trypan blue test, the total number of cells was significantly different between the irradiated groups and the CG at all times studied. The total number of cells increased in laser group (LG)1 (0.84 J) and LG2 (1.40 J) and decreased in LG4 (6.72 J). The mitochondrial activity increased significantly in LG1 and LG2 at 48 and 72 h and decreased in LG3 (5.88 J) and LG4 (6.72 J) compared with CG.
Conclusions: The results indicate that the lower doses (0.45 and 0.75 J/cm2 ) of PBM induce the highest mitochondrial activity and cellular viability.
Keywords: dose/response curve, photobiomodulation, red laser, fibroblasts, in vitro study
Lasers in Surgery and Medicine, 2013
Low-Level Laser Therapy for Fat Layer Reduction: A Comprehensive Review
Pinar Avci, MD,1,2,3 Theodore T. Nyame, MD,4 Gaurav K. Gupta, MD, PhD,1,2 Magesh, Sadasivam, MTech,1 and Michael R. Hamblin, PhD 1,2,5, 1 Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, 02114, Department of Dermatology, Harvard Medical School, Boston, Massachusetts, 02114 3 Department of Dermatology, Dermatooncology and Venerology, Semmelweis University School of Medicine, Budapest, 1085, Hungary, 4Division of Plastic and Reconstructive Surgery, Harvard Medical School, Boston, Massachusetts, 02115, 5Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts
Background and Objective: Low-level laser (light) therapy (LLLT) is a noninvasive, nonthermal approach to disorders requiring reduction of pain and inflammation and stimulation of healing and tissue regeneration. Within the last decade, LLLT started being investigated as an adjuvant to liposuction, for noninvasive body contouring, reduction of cellulite, and improvement of blood lipid profile. LLLT may also aid autologous fat transfer procedures by enhancing the viability of adipocytes. However the underlying mechanism of actions for such effects still seems to be unclear. It is important, therefore, to understand the potential efficacy and proposed mechanism of actions of this new procedure for fat reduction.
Methods: A review of the literature associated with applications of LLLT related to fat layer reduction was performed to evaluate the findings from preclinical and clinical studies with respect to the mechanism of action, efficacy, and safety.
Results: The studies as of today suggest that LLLT has a potential to be used in fat and cellulite reduction as well as in improvement of blood lipid profile without any significant side effects. One of the main proposed mechanism of actions is based upon production of transient pores in adipocytes, allowing lipids to leak out. Another is through activation of the complement cascade which could cause induction of adipocyte apoptosis and subsequent release of lipids.
Conclusion: Although the present studies have demonstrated safety and efficacy of LLLT in fat layer reduction, studies demonstrating the efficacy of LLLT as a standalone procedure are still inadequate. Moreover, further studies are necessary to identify the mechanism of action.
Gabriel Y.F. Ng, P.T., Ph.D., and Dicky T.C. Fung, P.T., Ph.D.
Objective: We examined the ultrastructural morphology (number of collagen fibrils, mean and mass-averaged diameter) of isolated and combined treatments of a therapeutic laser and herbs for medial collateral ligament (MCL) injury in rats.
Methods: Twenty-eight rats, divided into seven groups: laser (L), herb (H), laser herb (LH), laser control (LC), herb control (HC), laser sham (LS) and herb sham (HS), were studied. Right MCL of groups L, H, LH, LC and HC were transected, while that of LS and HS remained intact. Group L received 9 treatment sessions of GaAlAs laser with a dosage of 3.5 Jcm2; group H received herbal plaster treatment; groups LH had combined treatments of laser and herb; group LC had placebo laser; group LS had no treatment; groups HC and HS received only bandage without herb. All MCLs were analyzed using transmission electron microscopy at 3 weeks.
Results: Differences (p 0.05) existed in mean fibril diameters among groups. Core mass-averaged diameters of groups L and H were larger than the control groups (LC and HC). Fibril diameter of group LH (combined treatment) was even larger and approaching that of the intact MCL.
Conclusion: Combined therapeutic laser and herbal treatment hastened collagen fibril maturation in MCL repair.
Pugliese LS, Medrado AP, Reis SR, Andrade Zde A.
Pesqui Odontol Bras. 2003 Oct-Dec;17(4):307-13. Epub 2004 Apr 19.
Department of Basic Science, Foundation for the Development of Science, Salvador. The study of low-level laser therapy upon extracellular matrix elements is important to understand the wound healing process under this agent. However, little is known about the interference of laser light in relation to collagen and elastic fibers. Cutaneous wounds were performed on the back of 72 Wistar rats and a Ga-Al-As low-level laser was punctually applied with different energy densities. The animals were killed after 24, 48, 72 hours and 5, 7 and 14 days. Tissues were stained with hematoxilin-eosin, sirius red fast green and orcein and then analyzed. It was observed that the treated group exhibited larger reduction of edema and inflammatory infiltrate.
The treated animals presented a larger expression of collagen and elastic fibers, although without statistical significance (p > 0.05). Treatment with a dosage of 4 J/cm(2) exhibited more expressive results than that with 8 J/cm(2).
In this study, the authors concluded that low-level laser therapy contributed to a larger expression of collagen and elastic fibers during the early phases of the wound healing process.