Effect Of Low-level Laser Therapy (lllt) On Peripheral Nerve Regeneration Using Fibrin Glue Derived From Snake Venom.

The purpose of this study was to assess whether the adhesive permits the collateral repair of axons originating from a vagus nerve to the interior of a sural nerve graft, and whether low-level laser therapy (LLLT) assists in the regeneration process. Study sample consisted of 32 rats randomly separated into three groups: Control Group (CG; n=8), from which the intact sural nerve was collected; Experimental Group (EG; n=12), in which one of the ends of the sural nerve graft was coapted to the vagus nerve using the fibrin glue; and Experimental Group Laser (EGL; n=12), in which the animals underwent the same procedures as those in EG with the addition of LLLT. Ten weeks after surgery, the animals were euthanized. Morphological analysis by means of optical and electron microscopy, and morphometry of the regenerated fibers were employed to evaluate the results. Collateral regeneration of axons was observed from the vagus nerve to the interior of the autologous graft in EG and EGL, and in CG all dimensions measured were greater and presented a significant difference in relation to EG and EGL, except for the area and thickness of the myelin sheath, that showed significant difference only in relation to the EG. The present study demonstrated that the fibrin glue makes axonal regeneration feasible and is an efficient method to recover injured peripheral nerves, and the use of low-level laser therapy enhances nerve regeneration.

Comparison Between Single-Diode Low-Level Laser Therapy (LLLT) and LED Multi-Diode (Cluster) Therapy (LEDT) Applications Before High-Intensity Exercise

Background Data and Objective: There is anecdotal evidence that low-level laser therapy (LLLT) may affect the development of muscular fatigue, minor muscle damage, and recovery after heavy exercises. Although manufacturers claim that cluster probes (LEDT) maybe more effective than single-diode lasers in clinical settings, there is a lack of head-to-head comparisons in controlled trials. This study was designed to compare the effect of single-diode LLLT and cluster LEDT before heavy exercise. Materials and Methods: This was a randomized, placebo-controlled, double-blind cross-over study. Young male volleyball players (n = 8) were enrolled and asked to perform three Wingate cycle tests after 4 x 30 sec LLLT or LEDT pretreatment of the rectus femoris muscle with either (1) an active LEDT cluster-probe (660/850 nm, 10/30mW), (2) a placebo cluster-probe with no output, and (3) a single-diode 810-nm 200-mW laser. Results: The active LEDT group had significantly decreased post-exercise creatine kinase (CK) levels (-18.88 +/- 41.48U/L), compared to the placebo cluster group (26.88 +/- 15.18U/L) (p < 0.05) and the active single-diode laser group (43.38 +/- 32.90U/L) (p<0.01). None of the pre-exercise LLLT or LEDT protocols enhanced performance on the Wingate tests or reduced post-exercise blood lactate levels. However, a non-significant tendency toward lower post-exercise blood lactate levels in the treated groups should be explored further. Conclusion: In this experimental set-up, only the active LEDT probe decreased post-exercise CK levels after the Wingate cycle test. Neither performance nor blood lactate levels were significantly affected by this protocol of pre-exercise LEDT or LLLT.

Effects of Low-Level Laser Therapy (LLLT) in the Development of Exercise-Induced Skeletal Muscle Fatigue and Changes in Biochemical Markers Related to Postexercise Recovery

STUDY DESIGN: Randomized crossover double-blinded placebo-controlled trial. OBJECTIVE: To investigate if low-level laser therapy (LLLT) can affect biceps muscle performance, fatigue development, and biochemical markers of postexercise recovery. BACKGROUND: Cell and animal studies have suggested that LLLT can reduce oxidative stress and inflammatory responses in muscle tissue. But it remains uncertain whether these findings can translate into humans in sport and exercise situations. METHODS: Nine healthy male volleyball players participated in the study. They received either active LLLT (cluster probe with 5 laser diodes; A = 810 nm; 200 mW power output; 30 seconds of irradiation, applied in 2 locations over the biceps of the nondominant arm; 60 J of total energy) or placebo LLLT using an identical cluster probe. The intervention or placebo were applied 3 minutes before the performance of exercise. All subjects performed voluntary elbow flexion repetitions with a workload of 75% of their maximal voluntary contraction force until exhaustion. RESULTS: Active LLLT increased the number of repetitions by 14.5% (mean +/- SD, 39.6 +/- 4.3 versus 34.6 +/- 5.6; P = .037) and the elapsed time before exhaustion by 8.0% (P = .034), when compared to the placebo treatment. The biochemical markers also indicated that recovery may be positively affected by LLLT, as indicated by postexercise blood lactate levels (P<.01), creatine kinase activity (P = .017), and C-reactive protein levels (P = .047), showing a faster recovery with LLLT application prior to the exercise. CONCLUSION: We conclude that pre-exercise irradiation of the biceps with an LLLT dose of 6 J per application location, applied in 2 locations, increased endurance for repeated elbow flexion against resistance and decreased postexercise levels of blood lactate, creatine kinase, and C-reactive protein. LEVEL OF EVIDENCE: Performance enhancement, level 1b. J Orthop Sports Phys Ther 2010;40(8):524-532. doi:10.2519/jospt.2010.3294

Low level laser therapy (LLLT) decreases pulmonary microvascular leakage, neutrophil influx and IL-1 beta levels in airway and lung from rat subjected to LPS-induced inflammation

Background and Objective. Low level laser therapy (LLLT) is a known anti-inflammatory therapy. Herein we studied the effect of LLLT on lung permeability and the IL-1 beta level in LPS-induced pulmonary inflammation. Study Design/Methodology. Rats were divided into 12 groups (n = 7 for each group). Lung permeability was measured by quantifying extravasated albumin concentration in lung homogenate, inflammatory cells influx was determined by myeloperoxidase activity, IL-1P in BAL was determined by ELISA and IL-1P mRNA expression in trachea was evaluated by RT-PCR. The rats were irradiated on the skin over the upper bronchus at the site of tracheotomy after LPS. Results. LLLT attenuated lung permeability. In addition, there was reduced neutrophil influx, myeloperoxidase activity and both IL-1 beta in BAL and IL-1 beta mRNA expression in trachea obtained from animals subjected to LPS-induced inflammation. Conclusion. LLLT reduced the lung permeability by a mechanism in which the IL-1 beta seems to have an important role.

Anti-inflammatory effects of low-level laser therapy (LLLT) with two different red wavelengths (660 nm and 684 nm) in carrageenan-induced rat paw edema

It has been suggested that low-level laser therapy (LLLT) can modulate inflammatory processes. The aim of this experiment was to investigate what effects red laser irradiation with two different wavelengths (660 nm and 684 nm) on carrageenan-induced rat paw edema and histology. Thirty two male Wistar rats were randomly divided into four groups. One group received a sterile saline injection, while inflammation was induced by a sub-plantar injection of carrageenan (1 mg/paw) in the three other groups. After 1 h, LLLT was administered to the paw in two of the carrageenan-injected groups. Continuous wave 660 nm and 684 nm red lasers respectively with mean optical outputs of 30 mW and doses of 7.5 J/cm(2) were used. The 660 nm and 684 nm laser groups developed significantly (P < 0.01) less edema (0.58 ml [SE +/- 0.17] ml and 0.76 ml [SE +/- 0.10] respectively) than the control group (1.67 ml [SE +/- 0.191) at 4 h after injections. Similarly, both laser groups showed a significantly lower number of inflammatory cells in the muscular and conjunctive sub-plantar tissues than the control group.We conclude that both 660 nm and 684 nm red wavelengths of LLLT are effective in reducing edema formation and inflammatory cell migration when a dose of 7.5 J/cm(2) is used. (c) 2007 Elsevier B.V. All rights reserved.

Effects of LLLT in combination with bisphosphonate on bone healing in critical size defects: A histological and histometric study in rat calvaria

The purpose of this study was to analyze histologically the effect of low-level laser therapy (LLLT) in combination with bisphosphonate on bone healing in surgically created critical size defects (CSD) in rat calvaria. One hundred Wistar female rats sham operated (sham) and ovariectomized (Ovx) were maintained untreated for 1 month to allow for the development of osteopenia in the Ovx animals. A CSD was made in the calvarium of each rat, and the animals were divided into five groups according to following treatments: (1) sham rats (control), (2) Ovx rats, (3) Ovx rats treated with LLLT, (4) Ovx rats treated with bisphosphonate, and (5) Ovx rats treated with bisphosphonate and LLLT. Groups 4 and 5 were irrigated with 1 ml of bisphosphonate, and groups 3 and 5 were submitted to LLLT (GaAlAs), 660 nm, 24 J, and 0.4285 W/cm2 on the CSD. Ten animals of each treatment were killed at 30 and 60 days. Histomorphometric assessments, using image analysis software, and histological analyses were performed. No defect was completely regenerated with the bone. Histometrically, it can be observed that groups 3 (37.49 ± 1.94%, 43.11 ± 2.39%) and 5 (35.05 ± 1.57%, 41.07 ± 1.89%) showed a significant bone neoformation when compared to groups 1 (16.81 ± 1.57%, 27.54 ± 1.49%), 2 (11.68 ± 0.98%, 22.51 ± 1.05%), and 4 (14.62 ± 1.70%, 25.67 ± 1.41%) in all experimental periods (P < 0.05). It was possible to conclude that the LLLT associated or not with bisphosphonate treatment was effective for stimulating bone formation in CSD in the calvaria of rats submitted to ovariectomy. © 2012 Springer-Verlag London Ltd.

Effect of LLLT on autogenous bone grafts in the repair of critical size defects in the calvaria of immunosuppressed rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

New LLLT protocol to speed up the bone healing process-histometric and immunohistochemical analysis in rat calvarial bone defect

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of low-level laser therapy (LLLT) on peripheral nerve regeneration using fibrin glue derived from snake venom

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Low-level laser therapy (LLLT) in human progressive-intensity running: effects on exercise performance, skeletal muscle status, and oxidative stress

The aim of this work was to evaluate the effects of low-level laser therapy (LLLT) on exercise performance, oxidative stress, and muscle status in humans. A randomized double-blind placebo-controlled crossover trial was performed with 22 untrained male volunteers. LLLT (810 nm, 200 mW, 30 J in each site, 30 s of irradiation in each site) using a multi-diode cluster (with five spots - 6 J from each spot) at 12 sites of each lower limb (six in quadriceps, four in hamstrings, and two in gastrocnemius) was performed 5 min before a standardized progressive-intensity running protocol on a motor-drive treadmill until exhaustion. We analyzed exercise performance (VO(2 max), time to exhaustion, aerobic threshold and anaerobic threshold), levels of oxidative damage to lipids and proteins, the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and the markers of muscle damage creatine kinase (CK) and lactate dehydrogenase (LDH). Compared to placebo, active LLLT significantly increased exercise performance (VO(2 max) p = 0.01; time to exhaustion, p = 0.04) without changing the aerobic and anaerobic thresholds. LLLT also decreased post-exercise lipid (p = 0.0001) and protein (p = 0.0230) damages, as well as the activities of SOD (p = 0.0034), CK (p = 0.0001) and LDH (p = 0.0001) enzymes. LLLT application was not able to modulate CAT activity. The use of LLLT before progressive-intensity running exercise increases exercise performance, decreases exercise-induced oxidative stress and muscle damage, suggesting that the modulation of the redox system by LLLT could be related to the delay in skeletal muscle fatigue observed after the use of LLLT.

Inhomogeneity in optical properties of rat brain: a study for LLLT dosimetry.

Over the last few years, low-level light therapy (LLLT) has shown an incredible suitability for a wide range of applications for central nervous system (CNS) related diseases. In this therapeutic modality light dosimetry is extremely critical so the study of light propagation through the CNS organs is of great importance. To better understand how light intensity is delivered to the most relevant neural sites we evaluated optical transmission through slices of rat brain point by point. We experimented red (λ = 660 nm) and near infrared (λ = 808 nm) diode laser light analyzing the light penetration and distribution in the whole brain. A fresh Wistar rat (Rattus novergicus) brain was cut in sagittal slices and illuminated with a broad light beam. A high-resolution digital camera was employed to acquire data of transmitted light. Spatial profiles of the light transmitted through the sample were obtained from the images. Peaks and valleys in the profiles show sites where light was less or more attenuated. The peak intensities provide information about total attenuation and the peak widths are correlated to the scattering coefficient at that individual portion of the sample. The outcomes of this study provide remarkable information for LLLT dose-dependent studies involving CNS and highlight the importance of LLLT dosimetry in CNS organs for large range of applications in animal and human diseases.

Nociceptive scores and endorphin-containing cells reduced by low-level laser therapy (LLLT) in inflamed paws of Wistar rat

Objective: This study aimed to investigate how local pain relief is mediated by laser therapy and how dose affects the relationship. Methods: Inflammation was induced in the hind-paws of Wistar rats. Two groups of rats received 780-nm laser therapy (Spectra-Medics Pty Ltd.) at one of two doses (2.5 and 1 J/cm(2)). One group acted as a control. Scores of nociceptive threshold were recorded using paw pressure and paw thermal threshold measures. Results: A dose of 1 J/cm(2) had no statistically significant effect on antinociceptive responses. A dose of 2.5 J/cm(2) demonstrated a statistically significant effect on paw pressure threshold (p < 0.029) compared to controls. There was no difference in paw thermal threshold responses and paw volumes at either dose. Immunohistochemistry in control animals demonstrated normal beta-endorphin containing lymphocytes in control inflamed paws but no beta-endorphin containing lymphocytes in rats that received laser at 2.5 J/cm(2). Conclusion: The results confirm previous findings that the effect of laser therapy is dose-related. The mechanism of effect may occur via a differentiated pressure-sensitive neural pathway rather than a thermal-sensitive neural pathway. The significance of the immunohistochemistry findings remains unknown.

Low-level Laser Therapy To The Mouse Femur Enhances The Fungicidal Response Of Neutrophils Against Paracoccidioides Brasiliensis.

Neutrophils (PMN) play a central role in host defense against the neglected fungal infection paracoccidioidomycosis (PCM), which is caused by the dimorphic fungus Paracoccidioides brasiliensis (Pb). PCM is of major importance, especially in Latin America, and its treatment relies on the use of antifungal drugs. However, the course of treatment is lengthy, leading to side effects and even development of fungal resistance. The goal of the study was to use low-level laser therapy (LLLT) to stimulate PMN to fight Pb in vivo. Swiss mice with subcutaneous air pouches were inoculated with a virulent strain of Pb or fungal cell wall components (Zymosan), and then received LLLT (780 nm; 50 mW; 12.5 J/cm2; 30 seconds per point, giving a total energy of 0.5 J per point) on alternate days at two points on each hind leg. The aim was to reach the bone marrow in the femur with light. Non-irradiated animals were used as controls. The number and viability of the PMN that migrated to the inoculation site was assessed, as well as their ability to synthesize proteins, produce reactive oxygen species (ROS) and their fungicidal activity. The highly pure PMN populations obtained after 10 days of infection were also subsequently cultured in the presence of Pb for trials of protein production, evaluation of mitochondrial activity, ROS production and quantification of viable fungi growth. PMN from mice that received LLLT were more active metabolically, had higher fungicidal activity against Pb in vivo and also in vitro. The kinetics of neutrophil protein production also correlated with a more activated state. LLLT may be a safe and non-invasive approach to deal with PCM infection.

Measurements of jaw movements and TMJ pain intensity in patients treated with GaAlAs laser

The aim of this study was to evaluate the effectiveness of low-level laser therapy (LLLT) on the improvement of the mandibular movements and painful symptoms in individuals with temporomandibular disorders (TMD). Forty patients were randomly divided into two groups (n=20): Group 1 received the effective dose (GaAlAs laser ? 830 nm, 40 mW, 5J/cm2) and Group 2 received the placebo application (0 J/cm2), in continuous mode on the affected condyle lateral pole: superior, anterior, posterior, and posterior-inferior, twice a week during 4 weeks. Four evaluations were performed: E1 (before laser application), E2 (right after the last application), E3 (one week after the last application) and E4 (30 days after the last application). The Kruskal-Wallis test showed significant more improvements (p<0.01) in painful symptoms in the treated group than in the placebo group. A significant improvement in the range of mandibular movements was observed when the results were compared between the groups at E4. Laser application can be a supportive therapy in the treatment of TMD, since it resulted in the immediate decrease of painful symptoms and increased range of mandibular movements in the treated group. The same results were not observed in the placebo group.