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Light-emitting diode therapy in exercise-trained mice increases muscle performance, cytochrome c oxidase activity, ATP and cell proliferation

Cleber Ferraresi, Nivaldo Antonio Parizotto, Marcelo Victor Pires de Sousa, Beatriz Kaippert, Ying?Ying Huang, Tomoharu Koiso, Vanderlei Salvador Bagnato, Michael R. Hamblin - Wiley Online Library/ 09-01-2015 (Publication)
This research showed that the light group had significantly more ATP concentration than the control group.
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Abstract

Light-emitting diode therapy (LEDT) applied over the leg, gluteus and lower-back muscles of mice using a LED cluster (630 nm and 850 nm, 80 mW/cm2, 7.2 J/cm2) increased muscle performance (repetitive climbing of a ladder carrying a water-filled tube attached to the tail), ATP and mitochondrial metabolism; oxidative stress and proliferative myocyte markers in mice subjected to acute and progressive strength training. Six bi-daily training sessions LEDT-After and LEDT-Before-After regimens more than doubled muscle performance and increased ATP more than tenfold. The effectiveness of LEDT on improving muscle performance and recovery suggest applicability for high performance sports and in training programs.

 

Positioning of the mice and light-emitting diode therapy (LEDT) applied on mouse legs, gluteus and lower-back muscles without contact.

Introduction

Low-level laser (light) therapy has several applications in medicine such as treatment of pain 1, 2, tendinopathies 3 and acceleration of tissue repair 2, 4. Since the 1960s when the first laser (Light Amplification by Stimulated Emission of Radiation) devices were constructed, many applications of this therapy and its mechanisms of action have been investigated around the world 5.

Light therapy can be delivered by different light sources such as diode lasers or light emitting diodes (LEDs). These light sources differ in monochromaticity and coherence, since diode lasers are coherent with a tiny spectral bandwidth and less divergence of the light beams compared to the light emitted by LEDs 5. The spectral regions generally used for light therapy range between red (600 nm) to near infrared (1,000 nm) with total power in range of 1 mW–500 mW and power density (irradiance) in the range of range 1 mW–5 W/cm2 5. These lasers and LEDs are considered to produce equivalent effects on the tissue if the dose of light delivered/applied is in accordance with the possible biphasic dose?response previously reported 5-7. The light?tissue interaction depends on light absorption by specific structures in the cells that are known as chromophores 8-11.

Recently light therapy using lasers and LEDs has been used to increase muscle performance in exercises involving strength 12 or fatigue resistance 13-15; and light therapy may have a role to play in preparing athletes competing in high performance sports. Recent reviews have reported positive effects of light therapy on muscle performance, highlighting protection from exercise?induced muscle damage 16; an increased number of repetitions in maximum exertion tests 17; increased workload, torque and muscle fatigue resistance in training programs; as well as an overview of the main possible mechanisms of action of the light therapy on muscle tissue 18.

Several biological factors govern success or optimum performance in sports that involve high?intensity exercise, or alternatively involve endurance exercise, that both require muscle adaptation during pre?competition training programs. Among these factors are the depletion of the energy supply for muscle contraction which comprises adenosine triphosphate (ATP) and glycogen; accumulation of possibly deleterious metabolites from energy metabolism such as lactate, adenosine diphosphate (ADP), adenosine monophosphate (AMP), ions Ca2+ and H+; production of reactive oxygen species (ROS) 19-22; and the recovery process from microlesions or muscle damage 23. Light therapy seems to be able to benefit all these ”limitations” since its mechanism of action involves the improvement of mitochondrial metabolism and increased ATP synthesis 24, 25 owing to increased activity of cytochrome c oxidase (COX) in the electron transport chain (ETC) 9, 25, 26; reduction of reactive oxygen species (ROS) or improvement of oxidative stress defense 27, 28; and can stimulate faster muscle repair due to an increased proliferation and differentiation of muscle cells 29.

Experimental and clinical trials with different methodologies have reported the benefits of light therapy on muscle performance when applied before 15, 30, 31 or after exercise 12, 13, 32. However there is no consensus about the best time regimen for use of light therapy 18. The best wavelength (red or infrared) to stimulate muscle cells and increase muscle performance is also unclear.

In the current study we used an experimental model of mice exercising on a ladder similar to that reported in a previous study 33, in order to simulate a clinical strength training program that would allow us to identify which light therapy regimen would be better to increase muscle performance. Four different regimens of light therapy were applied to the mouse leg, gluteus and lower?back muscles during a training program: sham; before; before?after; and after each training session. Light therapy was delivered from LEDs (LEDT) with two simultaneous wavelengths (red and infrared). Assessment of muscle performance (load, number of repetitions, muscle work and power), markers of cellular energy and metabolism (ATP, glycogen and COX), oxidative stress markers (protein carbonyls, glutathione, catalase activity, lipid peroxidation, protein thiols) and muscle cell proliferation (BrdU – 5?bromo?2′?deoxyuridine) and adult myonuclei (DAPI – 4′,6?diamidino?2?phenylindole) were carried out.

Materials and methods

Animals

This study was performed with 8 week?old male Balb/c mice, weighing on average 22.22 g (SEM 0.24), housed at five mice per cage and kept on a 12 hour light 12 hour dark cycle. The 22 animals were provided by Charles River Inc and were provided with water and fed ad libitum at the animal facility of Massachusetts General Hospital. All procedures were approved by the IACUC of Massachusetts General Hospital (protocol #2014N000055) and met the guidelines of the National Institutes of Health.

Experimental groups

Twenty?two animals were randomly allocated into 4 exercise groups with 5 animals in each group, and 2 animals were allocated into an ”absolute” control group:

  • LEDT?Sham group: animals were treated with sham LEDT (LEDT device in placebo mode) over both legs, gluteus and lower?back muscles 5 minutes before each training session on ladder.

  • LEDT?Before: animals were treated with real LEDT over both legs, gluteus and lower?back muscles 5 minutes before each training session on ladder.

  • LEDT?Before?After: animals were treated with real LEDT over both legs, gluteus and lower?back muscles 5 minutes before and 5 minutes after each training session on ladder.

  • LEDT?After: animals were treated with real LEDT over both legs, gluteus and lower?back muscles 5 minutes after each training session on ladder.

  • Control: animals were not subjected to any LEDT or exercise or muscle performance assessment.

Ladder

An inclined ladder (80°) with dimensions of 100 cm × 9 cm (length and width, respectively) with bars spaced at 0.5 cm intervals was used in this study as reported in a previous study 33 (Figure 1).

Figure 1

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Ladder. Inclined ladder (80°) with 100 cm × 9 cm (length and width, respectively) used for the training program and muscle performance assessments. Falcon tube filled with water and attached to the mouse tail.

Load

A Falcon tube (50 ml) was filled with measured volumes of water and weighed using a precise scale. The target load was achieved adding or removing water from the tube and then this tube was attached to the mouse tail using adhesive tape (Figure 1). All loads were calculated in grams.

Procedures

The schedule of the various exercise procedures is described in Table 1.

Table 1. Schedule for exercise procedures

Day

Procedure

# repetitions

Load

Day 1

Familiarization

4 × 10 = 40

zero

Day 2

3RM baseline

3

Starting at 2 × BWa

Day 3

Training 1

5 × 10 = 50

0.8 × 3RMb

Day 5

Training 2

5 × 10 = 50

0.9 × 3RM

Day 7

Training 3

5 × 10 = 50

1.0 × 3RM

Day 9

Training 4

5 × 10 = 50

1.1 × 3RM

Day 11

Training 5

5 × 10 = 50

1.2 × 3RM

Day 13

Training 6

5 × 10 = 50

1.3 × 3RM

Day 14

3RM final

3

Starting at 3 × BW

  • a : body weight
  • b : average load carried during 3RM baseline measurement

Familiarization with ladder?climbing

All experimental groups, except Control group, were familiarized with climbing the ladder one day before the start of muscle performance assessment and training. The familiarization procedure was 4 sets of 10 climbs on the ladder (repetitions) with rest periods of 2 minutes between individual sets. No load was attached to the mouse tail during this procedure.

Three repetitions maximum load (3RM)

This test was the first evaluation of muscle performance and was set as the average of the maximum load carried by each animal during 3 consecutive full climbs of the inclined ladder (3RM). Slight pressure with tweezers was applied on mouse tail if the animal stopped during a climb. The test was stopped when mice were not able to climb or lost their grip on the ladder due to failure of concentric muscle contraction. The first attempt included a load corresponding to 200% of the individual mouse body weight. A maximum of 3 climb attempts was applied. If a mouse finished the climb the load was increased by 10% for the next climb, while if the mouse failed to finish a climb, the load was decreased by 10% for the next climb. The 3RM evaluation was performed twice; the first time was 24 h after familiarization procedure (baseline) and the second time was 24 h after the last training session (final).

Acute strength training protocol

After 24 h from initial 3RM baseline assessment, all experimental groups, except Control, were subjected to 6 training sessions carried out on alternate days (every 48 h). Each training session consisted of 5 sets of 10 repetitions (climbs) on the ladder with a rest period of 2 minutes between each set. If the animal could not complete a set or failed during a climb, the distance climbed (in cm) was measured and the rest period was started immediately. During some repetitions, a slight pressure on the mouse tail was performed with tweezers to stimulate the animal to climb and complete the exercise. If after three applications of gentle pressures the mouse could not resume climbing, and stopped or lost its grip on the ladder, the set of repetitions was stopped and the rest interval was started.

The number of repetitions in each set was measured as well as the time spent to complete the exercise. These data were used to calculate the muscle work and muscle power in each training session. The load of each training session was progressively increased and calculated as percentages of the 3RM (in grams) measured at baseline as follows: first training (80%), second training (90%), third training (100%), fourth training (110%), fifth training (120%) and sixth training (130%).

Light?emitting diode therapy (LEDT)

A non?commercial cluster of 40 LEDs (20 red – 630 ± 10 nm; 20 infrared – 850 ± 20 nm) with diameter of 76 mm was used in this study. A complete description of the LEDT parameters is presented in Table 2. The optical power reaching the surface of the mouse skin was measured with an optical energy meter PM100D Thorlabs® fitted with a sensor S142C (area of 1.13 cm2). All mice (except mice in Control) were shaved and fixed on a plastic plate using adhesive tapes. Afterwards, in accordance with experimental group, these animals were treated with LEDT over both legs, gluteus and lower?back muscles at a distance of 45 mm (without contact) (Figure 2). Irradiation lasted 90 s per session with fixed parameters as described in Table 1. LEDT placebo had no energy (0 J) and no power (0 mW) applied over the targeted muscles. The light dose was based on the possible biphasic dose response reported previously 5, 6. Moreover, dual wavelengths were chosen to function at the same time in this study based on specificities of the chromophores in the cells and therefore optimizing the effects of the light therapy (LEDT) by a double band of absorption 8-11.

Figure 2

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LEDT. Positioning of the mice and light?emitting diode therapy (LEDT) applied on mouse legs, gluteus and lower?back muscles without contact.

 

Muscle performance

The 3RM test was the first evaluation for muscle performance. This test measured the maximum load (in grams) carried by each animal during 3 consecutive full climbs on the inclined ladder.

During each training session the load, number of repetitions (rep), distance climbed and time spent to complete each repetition were recorded. These data were used to calculate muscle work and power.

Although the ladder had a total length of 100 cm available the maximum distance available to climb was set at 70 cm in order to avoid the load touching the floor. Thereby the muscle work was calculated as follows:

Work (J) = mgh

where ”m” is mass of the load (grams converted to kilogram) in each training session plus mouse body mass (values converted to kilogram); ”g” is acceleration due to gravity and ”h” is the distance climbed (converted to meters). Results were obtained in Joules (J) and presented as average ± standard error of mean (SEM) for each group at each training session.

Muscle power was calculated from results of muscle work (J) and time spent (s) to perform all repetitions of each set at all training sessions as follows:

Power (mW) = J/s

where ”J” is Joule and represents the muscle work performed and ”s” is time in seconds. Result were obtained in milliwatts (mW) and presented as average ± standard error of mean (SEM) per each group at each training session.

Muscular ATP

The gastrocnemius muscle from one leg of each animal was used for analysis of muscular ATP. Muscle samples were thawed in ice for 5 min, homogenized at a proportion of 3–4 mg of tissue to 500 µl of 10% perchloric acid (HClO4) following procedures previously published 34. Afterwards, an aliquot of 10 µl of the muscle homogenate plus 40 µl of CellTiter Glo Luminescent Cell Viability Assay mix (Promega), totaling 50 µl, were placed in the well microplate (CostarTM 96?Well White Clear?Bottom Plates). Luminescence signals were measured in a SpectraMax M5 Multi?Mode Microplate Reader (Molecular Devices, Sunnyvale, CA) with integration time of 5 s to increase low signals 34. A standard curve was prepared using ATP standard (Sigma) according to manufacturer's guidelines and then ATP concentration was calculated in nanomol (nmol) per milligram (mg) of protein. An aliquot of muscle homogenate was used to quantify the total protein by QuantiProTM BCA Assay kit (Sigma?Aldrich) following manufacturer's guidelines.

Muscular glycogen

Quadriceps femoris muscles were thawed in ice for 30 min and muscular glycogen was measured in 50 mg of quadriceps femoris tissue homogenized with 6 N NaOH at a proportion of 50 mg/ml. A standard curve was prepared using absolute ethanol (100%), K2SO4 (10%), phenol (4.1%) and 1 mM of glucose (2%) according to Dubois et al. 35. Optical density was read at 480 nm in spectrophotometer (EvolutionTM 300 UV?Vis, software VISPRO – Thermo Scientific). Data were normalized per mg of muscle tissue.

Oxidative stress markers

Protein carbonyl: Quadriceps femoris muscles were homogenized in deionized water (dH2O) at a proportion of 10 mg/200 µl. Protein carbonyl content was quantified using Protein Carbonyl Content Assay kit (Biovision) with the colorimetric method and following manufacturer's guidelines. All results were normalized per total protein quantified by QuantiProTM BCA Assay kit (Sigma?Aldrich) following manufacturer's guidelines.

Glutathione: Quadriceps femoris muscles were homogenized in 100 mM ice cold phosphate buffer (pH = 7.4) at a proportion of 10 mg/250 µl. Phosphate buffer was prepared with dibasic (Na2HPO4) and monobasic (NaH2PO4) sodium phosphate at equal proportions. Total and oxidized glutathione analysis was carried out with Glutathione Colorimetric Assay kit (ARBOR Assays) following manufacturer's guidelines. In addition, all results were normalized per total protein of the samples using QuantiProTM BCA Assay kit (Sigma?Aldrich) following manufacturer's guidelines.

Catalase activity: Quadriceps femoris muscles were homogenized in cold assay buffer provided in a Catalase Activity Assay kit (Biovision) at a proportion of 50 mg/100 µl. This analysis used the colorimetric method and followed manufacture's guidelines.

Lipid peroxidation using TBARS (Thiobarbituric Acid Reactive Substances): Quadriceps femoris muscles were homogenized with RIPA Buffer (Sigma?Aldrich) at a proportion of 25 mg/250 µl. Next, TBARS Colorimetric Assay kit (Cayman Chemical) was used following manufacturer's guidelines.

Protein Thiols: Quadriceps femoris muscles were homogenized in ice cold 100 mM phosphate buffer at a proportion of 10 mg/250 µl. Next, a Fluorescent Protein Thiol Detectiont kit (ARBOR Assays) was used following manufacturer's guidelines. In addition, all results were normalized per total protein quantified by QuantiProTM BCA Assay kit (Sigma?Aldrich) following manufacturer's guidelines.

Immunofluorescence analyses

5?bromo?2′?deoxyuridine (BrdU): BrdU reagent (Sigma?Aldrich) was diluted in saline solution (PBS) at a concentration of 10 mg/ml. Next, during the last 8 days of the experiment all animals (including Control group) received a single daily intra peritoneal injection (50 mg/kg) of BrdU. Mice were anesthetized and submitted to surgical procedures described previously. Gastrocnemius muscles were embedded in paraffin, cut in axial slices of 5 µm thickness from the muscle belly region by a microtome and mounted on slides for immunohistochemical procedures. Briefly, slides were deparaffinized with graded ethanol and then passed through antigen retrieval solution in a water bath pre?heated at 98 °C for 30 min. Afterwards slides were washed and incubated for 15 min at room temperature with 0.1% Triton X?100 TBS for cell membrane permeabilization, washed again and incubated for 30 min in protein blocking solution consisting of 3% BSA (Bovine Serum Albumin – Sigma) and 10% goat serum in TBS. Next, slides were immunostained with sheep anti?BrdU (Ab1893 – Abcam, Cambridge, MA) at 1 : 50 working concentration and selected anti?sheep (Alexa Fluor® 647 – Invitrogen) fluorescent secondary antibody matched to the primary antibody to stain at 1 : 200 working concentration. Finally, slides were cover?slipped with mounting media containing DAPI (4′,6?diamidino?2?phenylindole) (Invitrogen). Cells positively stained for BrdU were imaged using confocal microscope (Olympus America Inc. Center Valley, PA, USA) from three random fields. BrdU and DAPI staining were quantified using software Image J (NIH, Bethesda, MD).

Cytochrome c oxidase subunit IV (COX IV): Gastrocnemius muscles were subjected to the same procedures described for BrdU staining. Slides were immunostained with rabbit anti?COX IV (Cell Signaling Technology®) at 1 : 500 working concentration and selected anti?rabbit (Alexa Fluor® 680 – Invitrogen) secondary antibody matched with primary antibody to stain at 1 : 200 working concentration. Cells positively stained for COX IV were imaged using confocal microscopy as above and then the red channel of the exported images was changed to yellow.

Statistical analysis

Shapiro?Wilk's W test verified the normal distribution of the data. All experimental groups subjected to training protocols were compared at each training session for number of repetitions, muscle work and muscle power using one?way analysis of variance (ANOVA) and Tukey HSD post?hoc test. The load of 3RM among these same groups was compared by Two?way ANOVA with repeated measures (baseline versus final) and Tukey HSD post?hoc test. For muscular ATP, glycogen, oxidative stress markers and immunofluorescence stains, all experimental groups were compared by one?way ANOVA and Tukey's HSD post?hoc test. Significance was set at p < 0.05.

 

Results

Muscle performance

3RM: The final load 3RM was significantly higher (p < 0.05) in all experimental groups at the end of the experiment period compared to baseline. The final load of LEDT?After (92.28 g, SEM 0.82) was higher than LEDT?Sham (59.58 g, SEM 5.28; p < 0.001) and LEDT?Before (78.98 g, SEM 1.96; p = 0.020). In addition, LEDT?Sham had a significantly lower final load (p < 0.001) compared to LEDT?Before as well as LEDT?Before/After (83.91 g, SEM 1.49) (Figure 4A).

Figure 4

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Muscle performance (n = 5 animals per group). (A) Baseline and Final test of 3 repetitions maximum (3RM) measuring the total load carried by mice during this test. * statistical significance (p < 0.05) comparing the final 3RM load between groups. (B) Number of repetitions or climbs performed by each group treated with different regimens of LEDT during the progressive training program. (C) Muscle power developed by each group treated with different regimens of LEDT during the progressive training program. (D) Muscle work developed by each group treated with different regimens of LEDT during the progressive training program. * statistical significance (p < 0.05) compared to LEDT?Sham. # statistical significance (p < 0.05) compared to LEDT?After. & statistical significance (p < 0.05) compared to LEDT?Before. Abbreviations: LEDT = light?emitting diode therapy; LEDT?Sham (Sham – S) = LEDT placebo (LEDT device in placebo mode) on muscles immediately before (5 minutes) each training session on ladder; LEDT?Before (Before – B) = LEDT applied on muscles immediately before (5 minutes) each training session on ladder; LEDT?Before?After (Before?After – A?B) = LEDT applied on muscles immediately before (5 minutes) and immediately after (5 minutes) each training session on ladder; LEDT?After (After – A) = LEDT applied on muscles immediately after (5 minutes) each training session on ladder. The load of 3RM at baseline versus final was analyzed by Two?way analysis of variance (ANOVA) with repeated measures. Number of repetitions, muscle work and power were analyzed by One?way ANOVA.

Number of repetitions: There were significantly differences (p < 0.05) between all groups in each training session (Figure 4B). At 80% of 3RM (first session): animals in LEDT?Before and LEDT?Before?After groups performed more repetitions compared to animals in LEDT?Sham and LEDT?After (p < 0.01) groups. At 90% of 3RM (second session): animals in LED?Sham group performed fewer repetitions than animals in LEDT?Before, LEDT?Before?After and LEDT?After groups (p < 0.001). At 100% of 3RM (third session): animals in LEDT?Sham group performed fewer repetitions compared to animals in LEDT?Before (p = 0.014), LED?Before?After (p = 0.010) and LEDT?After (p = 0.002) groups. At 110% of 3RM (fourth session): animals in LEDT?Sham group performed fewer repetitions than animals in LEDT?Before?After (p = 0.013) and LEDT?After (p = 0.009) groups. At 120% of 3RM (fifth session): animals in LEDT?After group performed more repetitions than animals in LEDT?Before (p = 0.022) and LEDT?Sham (p < 0.001) groups. In addition, animals in LEDT?Sham performed fewer repetitions than animals in LEDT?Before (p = 0.022), LEDT?Before?After and LEDT?After (p < 0.001) groups. At 130% of 3RM (sixth session): animals in LEDT?Before?After and LEDT?After groups performed more repetitions than animals in LEDT?Sham (p < 0.001) and LEDT?Before (p < 0.01) groups.

Muscle Power: At 80% of 3RM there were no significant differences among all groups (p > 0.05). At 90% of 3RM: animals in LEDT?Sham group had lower muscle power compared to animals in LEDT?Before, LEDT?Before?After and LEDT?After (p < 0.01) groups. At 100% of 3RM: animals in LEDT?Sham group had lower muscle power than animals in LEDT?Before?After (p = 0.025) and LEDT?After (p = 0.007) groups. At 110% of 3RM: animals in LEDT?Before?After group developed more muscle power than animals in LEDT?Sham (p < 0.001) and LEDT?Before (p = 0.013) groups. In addition, animals in LEDT?After group had more muscle power than animals in LEDT?Sham (p = 0.002) group. At 120% of 3RM: animals in LEDT?Before?After and LEDT?After groups developed more muscle power than animals in LEDT?Sham and LEDT?Before (p < 0.001) groups. At 130% of 3RM: animals in LEDT?Before?After group developed more muscle power than animals in LEDT?Sham and LEDT?Before (p < 0.001) as well as LEDT?After (p = 0.001) groups. In addition, animals in LEDT?After group had more muscle power than animals in LEDT?Sham (p < 0.001) and LEDT?Before (p = 0.004) groups. Finally, animals in LEDT?Before group had major muscle power than animals in LEDT?Sham (p = 0.020) group (Figure 4C).

Muscle Work: Similar to results presented in Figure 4B, at 80% of 3RM only animals in LEDT?Before and LEDT?Before?After groups performed more muscle work compared to LEDT?Sham (p < 0.05) group (Figure 4D). At 90% of 3RM: animals in LEDT?Sham group performed less muscle work than animals in LEDT?Before, LEDT?Before?After and LEDT?After (p < 0.001) groups. These results were similar at 100% of 3RM (p < 0.001). At 110% of 3RM: animals in LEDT?Sham group had lower muscle work compared to animals in LEDT?Before?After (p = 0.015) and LEDT?After (p = 0.011) groups. At 120% of 3RM: animals in LEDT?Sham group performed lower muscle work compared to animals in LEDT?Before (p = 0.027) and LEDT?Before?After and LEDT?After (p < 0.001) groups. In addition, animals in LEDT?After group performed more muscle work than animals in LEDT?Before (p = 0.026) group. At 130% of 3RM: animals in LEDT?Before?After and LEDT?After groups performed more muscle work than animals in LEDT?Sham (p < 0.001) and LEDT?Before (p < 0.01) groups (Figure 4D).

Muscle ATP content

Animals in LEDT?After group had significantly (p < 0.001) more ATP concentration (1,367.64 nmol/ mg protein, SEM 105.30) compared to animals in LEDT?Sham (15.85 nmol/mg protein, SEM 5.14), LEDT?Before (81.00 nmol/ mg protein, SEM 10.11), LEDT?Before?After (687.62 nmol/ mg protein, SEM 11.76) and Control (17.53 nmol/mg protein, SEM 7.47) groups. In addition, animals in LEDT?Before?After group had also major contents of ATP compared to animals in LEDT?Before, LEDT?Sham and Control (p < 0.001) groups (Figure 5A).

 

 

 

Figure 5

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Muscular ATP and glycogen contents (n = 5 animals per group). (A) Adenosine triphosphate (ATP) contents in gastrocnemius muscle after the training program. (B) Glycogen contents in quadriceps femoris muscles after the training program. * statistical significance (p < 0.05). Abbreviations: LEDT = light?emitting diode therapy; LEDT?Sham (Sham – S) = LEDT placebo (LEDT device in placebo mode) on muscles immediately before (5 minutes) each training session on ladder; LEDT?Before (Before – B) = LEDT applied on muscles immediately before (5 minutes) each training session on ladder; LEDT?Before?After (Before?After – A?B) = LEDT applied on muscles immediately before (5 minutes) and immediately after (5 minutes) each training session on ladder; LEDT?After (After – A) = LEDT applied on muscles immediately after (5 minutes) each training session on ladder. Control (C) = no exercise or muscle performance assessment. Comparisons among all groups were conducted using One?way analysis of variance (ANOVA).

 

 

 

Muscle glycogen content

Animals in LEDT?After (137.76 nmol/mg tissue, SEM 11.40) and LEDT?Before?After (144.44 nmol/ mg tissue, SEM 16.23) groups had significantly higher concentrations of glycogen in quadriceps femoris muscles (p < 0.001) compared to animals in LEDT?Sham (31.36 nmol/mg tissue, SEM 7.45), LEDT?Before (52.76 nmol/mg tissue, SEM 6.53) and Control (58.78 nmol/ mg tissue, SEM 7.17) groups (Figure 5B).

Oxidative stress markers

Total glutathione: Animals in Control group (1.33 µM/µg protein, SEM 0.11) had a significantly higher concentration of total glutathione compared to animals in LEDT?Sham (0.097 µM/µg protein, SEM 0.046; p = 0.005) and LEDT?Before (1.00 µM/µg protein, SEM 0.02; p = 0.010) groups (Figure 6A).

Figure 6

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Oxidative stress markers (n = 5 animals per group) in quadriceps femoris muscles. (A) Total Glutathione (reduced glutathione – GSH). (B) Oxidized Glutathione (GSSG). (C) Protein Carbonyl. (D) Catalase activity. (E) Lipid peroxidation using TBARS (Thiobarbituric Acid Reactive Substances). (F) Protein Thiol. * statistical significance (p < 0.05). Abbreviations: LEDT = light?emitting diode therapy; LEDT?Sham (Sham – S) = LEDT placebo (LEDT device in placebo mode) on muscles immediately before (5 minutes) each training session on ladder; LEDT?Before (Before – B) = LEDT applied on muscles immediately before (5 minutes) each training session on ladder; LEDT?Before?After (Before?After – A?B) = LEDT applied on muscles immediately before (5 minutes) and immediately after (5 minutes) each training session on ladder; LEDT?After (After – A) = LEDT applied on muscles immediately after (5 minutes) each training session on ladder. Control (C) = no exercise or muscle performance assessment. Comparisons among all groups were conducted using One?way analysis of variance (ANOVA).

Oxidized glutathione: Animals in LEDT?Sham group (0.005 µM/µg protein, SEM 0.001) had significantly minor concentration of glutathione oxidized compared to animals in LEDT?Before (0.20 µM/µg protein, SEM 0.002; p = 0.015), LEDT?Before?After (0.035 µM/µg protein, SEM 0.003; p < 0.001), LEDT?After (0.041 µM/µg protein, SEM 0.003; p < 0.001) and Control (0.027 µM/µg protein, SEM 0.007; p = 0.006) groups. In addition, animals in LEDT?Before group had significantly minor concentration of oxidized glutathione compared to animals in LEDT?After (p < 0.001) and LEDT?Before?After (p = 0.024) groups (Figure 6B).

Protein carbonyl: Animals in LEDT?After group (1.40 nmol/µg protein, SEM 0.15) had significantly lower concentrations of protein carbonyls compared to animals in LEDT?Sham (6.31 nmol/µg protein, SEM 1.09; p = 0.030), LEDT?Before (6.81 nmol/µg protein, SEM 1.21; p = 0.040) and LEDT?Before?After (8.27 nmol/µg protein, SEM 2.35; p = 0.008) groups (Figure 6C).

Catalase activity: Animals in LEDT?Sham group (2.11 nmol/min/ml, SEM 0.10) had significantly lower catalase activity (p < 0.01) compared to animals in LEDT?Before?After (4.33 nmol/min/ml, SEM 0.62), LEDT?After (4.22 nmol/min/ml, SEM 0.37) and Control (4.47 nmol/min/ml, SEM 0.52) groups (Figure 6D).

Lipid peroxidation using TBARS: There were no significant differences between any of the groups (p > 0.05) assessed. Animals in Control group had a concentration of 21.29 µM (SEM 1.13); animals in LEDT?Sham had 21.12 µM (SEM 2.86); animals in LEDT?Before had 23.87 µM (SEM 1.13); animals in LEDT?Before?After had 19.19 µM (SEM 1.01) and animals in LEDT?After had 19.55 µM (SEM 1.24) (Figure 6E).

Protein Thiols: There were no sig


Original Source: https://onlinelibrary-wiley-com.colorado.idm.oclc.org/doi/full/10.1002/jbio.201400087

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This tool is a searchable collection of technical publications, books, videos and other resources about the use of lasers and light for PhotoBioModulation (PBM). Enter a keyword above or see some of our favorite queries below. 

Here are some of our favorite queries:

 

All the resources include links to the original source so we are not making any statement about the use of lasers for treating non-FDA cleared application, we are simple summarizing what others have said.

Where every possible, we have included a link to the orginal publication.

This tool uses a broad match query so:

  • It does not correct spelling and searches only cold laser related subjects so do not use LLLT, cold or laser in the search bar
  • It works better with shorter search terms or even parts of search terms
  • It searches all the available fields so you can enter a body part, author, condition or laser brand.
  • Where ever possible, the detailed section about the resource will link to the sources.
  • This system is only for photobiomodulation or cold laser therapy research (including LLLT, laser acupuncture and high power laser therapy) only. It does NOT include photodynamic laser therapy (where the laser is used to react with a pharmaceutical), hot surgery lasers or cosmetic lasers. It does include some resources on weight loss and smoking cessation.

The results of the search are sorted based on 3 quality factors on a scale of 1 to 10 with 10 being the best score. Originally all the resources were given a 5-5-5 until they could be individually evaluated. These scores are purely opinion and are only used to simplify the rank of the results from more valuable to least valuable. This should not be considered a critique of any work. This system was created to help researchers (including ourselves) find the most usable resources for any cold laser therapy research. The resources are assigned values based on the following 3 factors:

  • Efficacy: The resource (especially research papers) should show a significant improvement in the condition being treated. Resources that show better results are given a higher quality score.
  • Detail: The source must give enough information that the results can be duplicated. If a resource lacks too many details that it cannot be recreated, it is given a lower detail score.
  • Lack of Bias: Many resources are created to try and show that one device is superior to its competition. Many manufacturers have staff that crank out biased papers on a regular basis on the hope that this will make their product look superior. If the author of the resource is paid by a manufacturer of the resource appears to be biased towards one device and not one technology, the resource has much less value.

Over the past few years of working with research, we found that a majority of the published resources are lacking in one of these three ranking factors.
The original goal of this research tool was to tie published resources to the protocols in the laser-therapy.us library. This connection allows users to trace each protocol back to a list of resources so the protocol can be researched and improved.

General Comments


POWER
When many of the first research papers were published, the most power laser available for therapy were less than 100mW and many systems had to be pulsed to keep the laser from burning out too quickly. Today, system are available that will deliver up to 60,000mW of continuous output. Because of these power limitation, many early studies were limited to extremely low dosages by today’s standards. It takes a 50mW system 17 minutes to deliver 50 joules at the surface of the skin. If this was spread over a large area of damage or was treating a deeper problem, the actual dosages were much less than 1J/cm2.  Today, we know that these dosages typically produce very little or no results.
WAVELENGTH
About 80% of the resources in this database are in the near infrared wavelength. There is also some interest in the red wavelength (600 to 660nm) . Other wavelengths like blue, purple, and green have very little scientific research behind them and have not gotten much traction in the core therapy market with the exception of some fringe consumer products.
Legal Disclaimer
This research tool is free to use but we make no claims about the accuracy of the information. It is an aggregation of existing published resources and it is up to the user to determine if the source of the resources has any value. The information provided through this web site should not be used for diagnosing or treating a health problem or disease. If you have or suspect you may have a health problem, you should consult your local health care provider.



Light House Health Introduction

LightHouse - (Website)
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Welcome to the Lighthouse Health Education Center. There are over 5000 successful studies showing the efficacy of PBM, light therapy and sound therapy. This is a searchable collection of technical publications, books, videos and other resources about the best practices in the industry and about treating a wide variety of problems. All the resources include links to the original source (where available) so we are not making any claims about the use of our technology for treating "non-FDA cleared" applications, we are simply summarizing what the expert are saying about proper application of these technologies.

Enter a keyword above and click on one of the following links to see a set of publications about that subject. HINT: Shorter keywords work better.

Here are some of our favorite queries:

Testimonials

Research Info for other Applications

Autoimmune Research

Contraindications

This tool uses a broad match query so:

  • It does not correct spelling and searches only cold laser related subjects so do not use LLLT, cold or laser in the search bar
  • It works better with shorter search terms or even parts of search terms
  • It searches all the available fields so you can enter a body part, author, condition or laser brand.
  • This system is only for photobiomodulation or cold laser therapy research (including LLLT, laser acupuncture and high power laser therapy) only. It does NOT include photodynamic laser therapy (where the laser is used to react with a pharmaceutical), hot surgery lasers or cosmetic therapies.


The query result(s) can be shared using the following direct link. Anyone who clicks on this link in an email or on a web site will be shown the current results for the query.
http://www.laser-therapy.us/research/index.cfm?researchinput=athletictestimonials