Low-Level Laser Therapy Reduces Delayed Hypersensitivity Reaction to Ovalbumin in Balb/C Mice

Efficacy of Low-Level Laser Therapy in a Rabbit Model of Rhinosinusitis

Little is known about alternative treatment options for rhinosinusitis (RS). We aimed to evaluate the efficacy of low-level laser therapy (LLLT) for RS in experimentally induced rabbit models of RS. A total of 18 rabbits were divided into four groups: a negative control group (n = 3), an RS group without treatment (n = 5, positive control group), an RS group with natural recovery (n = 5, natural recovery group), and an RS group with laser irradiation (n = 5, laser-treated group). Computed tomography and histopathological staining were performed for each group. mRNA and protein expression levels of local cytokines (IFN-γ, IL-17, and IL-5) were also measured. Tissue inflammation revealed a significant improvement in the laser-treated group compared with the RS and natural recovery groups (p < 0.01). In addition, sinus opacification in the CT scans and cytokine expression was reduced in the laser-treated group, though without statistical significance. LLLT could be an effective option for the management of RS concerning radiological, histological, and molecular parameters.

Clinical Efficacy and Safety of Low-Level Laser Therapy in Patients with Perennial Allergic Rhinitis: A Randomized, Double-Blind, Placebo-Controlled Trial

Allergic rhinitis (AR) is a common disease that interferes with the daily activities and reduces the quality of life. Conventional treatments often do not provide complete resolution of the symptoms, and many new treatment modalities have been tried. This study aimed to evaluate the efficacy and safety of low-level laser therapy (LLLT) for AR in a randomized, double-blind, placebo-controlled trial. Patients diagnosed with AR were randomly allocated to receive LLLT or sham treatment. The primary outcome was a change in the reflective total nasal symptom score (TNSS). The secondary outcome was quality of life scores assessed using the Rhinoconjunctivitis Quality of Life Questionnaire. Incidences of adverse events were also recorded. Among 67 randomized subjects, 41 subjects (22 in LLLT group and 19 in sham treatment group) were included for efficacy analysis. The LLLT group showed a significantly improved TNSS score compared to the sham treatment group for decreasing AR symptom severity (p = 0.011) and improving quality of life regarding nasal symptoms (p = 0.036) at the end of treatment. Throughout the treatment period, no severe adverse events occurred. This clinical trial showed that LLLT is an effective and safe option for the management of AR regarding symptom relief and quality of life improvement.

Effects of Low-Level Laser Irradiation in a Mouse Model of Allergic Rhinitis

BACKGROUND AND OBJECTIVES

To evaluate the antiallergic effect of low-level laser irradiation (LLLI) at 650 nm in a mouse model of allergic rhinitis (AR), and to examine the underlying mechanisms.

STUDY DESIGN/MATERIALS AND METHODS

BALB/c mice were sensitized with ovalbumin (OVA) and alum and challenged intranasally with OVA. Straight- and diffusion-type LLLI were applied directly into the intranasal cavity of the mice once daily for 10 days (650 nm, 5 mW, 15 min/day) and multiple allergic parameters were evaluated.

RESULTS

LLLI reduced allergic symptoms, such as rubbing and sneezing, and suppressed the serum total immunoglobulin E (IgE), OVA-specific IgE, and OVA-specific IgG1 levels. Diffusion-type LLLI significantly reduced eosinophil infiltration of nasal mucosa and lymph nodes (LNs). LLLI reduced the expression of interleukin-4 (IL-4) and IL-17 in cervical LN and splenocyte culture supernatant, as well as their messenger RNA levels in nasal mucosa. However, the expression of interferonγ (IFN-γ) and IL-6 was unaffected by LLLI. The levels of reactive oxygen species (ROS) and nitric oxide (NO) in LN cells and the nasal mucosa, which were increased in the AR group, were reduced by LLLI, suggesting involvement of ROS and NO within their mechanism.

CONCLUSIONS

LLLI exerted an antiallergic effect by decreasing local and systemic IL-4, IL-17, and IgE levels, as well as eosinophilic infiltration into the nasal mucosa, in a mouse model of AR by modulating ROS and NO levels. Diffusion-type LLLI exhibited greater efficacy against AR than straight-type LLLI. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Low-level laser therapy ameliorates disease progression in a mouse model of multiple sclerosis

Multiple sclerosis (MS) is an autoimmune demyelinating inflammatory disease characterized by recurrent episodes of T cell-mediated immune attack on central nervous system (CNS) myelin, leading to axon damage and progressive disability. The existing therapies for MS are only partially effective and are associated with undesirable side effects. Low-level laser therapy (LLLT) has been clinically used to treat inflammation, and to induce tissue healing and repair processes. However, there are no reports about the effects and mechanisms of LLLT in experimental autoimmune encephalomyelitis (EAE), an established model of MS. Here, we report the effects and underlying mechanisms of action of LLLT (AlGaInP, 660 nm and GaAs, 904 nm) irradiated on the spinal cord during EAE development. EAE was induced in female C57BL/6 mice by immunization with MOG35-55 peptide emulsified in complete Freund's adjuvant. Our results showed that LLLT consistently reduced the clinical score of EAE and delayed the disease onset, and also prevented weight loss induced by immunization. Furthermore, these beneficial effects of LLLT seem to be associated with the down-regulation of NO levels in the CNS, although the treatment with LLLT failed to inhibit lipid peroxidation and restore antioxidant defense during EAE. Finally, histological analysis showed that LLLT blocked neuroinflammation through a reduction of inflammatory cells in the CNS, especially lymphocytes, as well as preventing demyelination in the spinal cord after EAE induction. Together, our results suggest the use of LLLT as a therapeutic application during autoimmune neuroinflammatory responses, such as MS.

Treatment of upper limb lymphedema with low-level laser: a systematic review

Introduction Low-level lasers have been suggested as a complement to lymphedema treatment. However, this therapy’s mechanism of action and its effects are poorly understood up to the present. Objective To conduct a systematic literature review to analyze the effects of low-level laser in the treatment of upper-limb lymphedema in women submitted to breast cancer surgery. Material and methods Randomized clinical trials were included, in Portuguese, English and Spanish, from January 1990 to July 2013. The article search was carried out in the Pubmed, Lilacs and PEDro electronic databases, with the following descriptors:Terapia a Laser de Baixa Intensidade, Linfedema, Câncer de Mama, Low-level laser therapy, Lymphedema, Breast Neoplasms and also through a manual search. Results and discussion Low-level lasers have been used for treating several acute and chronic conditions. However, its application for managing post breast cancer surgery is still recent, often based on empirical evidence. Treating upper-limb lymphedema with low-level laser presented positive results, with reduction in the circumference or volume of the affected limb. Conclusion More studies of high methodological quality are needed in order to better understand the mechanism of action of low-level laser on the lymphatic system and its effects on lymphedema treatement.

Effects of low level laser therapy on ovalbumin-induced mouse model of allergic rhinitis

Introduction. This study was designed to investigate the effects of low level laser therapy (LLLT) on experimental allergic rhinitis (AR) models induced by ovalbumin. Materials and Methods. AR was induced by 1% ovalbumin in mice. Twenty-four mice were divided into 4 groups: normal, control, low, and high dose irradiation. Low and high dose LLLT were irradiated once a day for 7 days. Total IgE, cytokines concentrations (IL-4 and IFN-γ), and thymus and activation regulated chemokine (TARC) were measured. Histological changes in the nasal mucosal tissue by laser irradiation were examined. Results. LLLT significantly inhibited total IgE, IL-4, and TARC expression in ovalbumin-induced mice at low dose irradiation. The protein expression level of IL-4 in spleen was inhibited in low dose irradiation significantly. IL-4 expression in EL-4 cells was inhibited in a dose dependent manner. Histological damages of the epithelium in the nasal septum were improved by laser irradiation with marked improvement at low dose irradiation. Conclusion. These results suggest that LLLT might serve as a new therapeutic tool in the treatment of AR with more effectiveness at low dose irradiation. To determine the optimal dose of laser irradiation and action mechanisms of laser therapy, further studies will be needed.

Low-level laser reduces the production of TNF-α, IFN-γ, and IL-10 induced by OVA

Delayed, or type IV, hypersensitivity reactions are a useful model to study the effects of new substances on the immune system. In this study, the experimental model of the delayed type hypersensitivity (DTH) reaction to ovalbumin (OVA) was used to evaluate the immunomodulating effects of low-level laser therapy (LLLT), which is used as an adjuvant therapy in medicine, dentistry, and physical therapy because of its potential anti-inflammatory and analgesic effects observed in several studies. The effects of LLLT (λ 780 nm, 0.06 W/cm(2) of radiation, and fluency of 3.8 J/cm(2)) in reaction to ovalbumin in Balb/C mice were examined after the induction phase of the hypersensitivity reaction. The animals treated with azathioprine (AZA), the animals that received a vehicle instead of ovalbumin, and those not immunized served as controls (n = 6 for each group). Footpad thickness measurements and hematoxylin-eosin histopathological exams were performed. Proliferation tests were also performed (spontaneous, in the presence of concanavalin A and ovalbumin) to determine the production in mononuclear cells cultures of tumor necrosis factor-alpha (TNF-α), INF-γ, and IL-10. In the group of animals irradiated with lasers and in the group treated with AZA, footpad thickness measurements were significantly reduced in comparison to the control group (p < 0.05). This reduction was accompanied by a very significant reduction in the density of the inflammatory infiltrate and by a significant reduction in the levels of TNF-α, INF-γ, and IL-10. LLLT radiation was shown to have an immunomodulating effect on DTH to OVA in Balb/C mice.