Photobiomodulation and amniotic membrane for treat tendon injury in rats

Tendons, complex fibrous structures, are subjected to great tensions, which can give rise to the so-called tendinopathies. This study aimed to evaluate photobiomodulation and human Amniotic Membrane applied as single or combined therapies to treat induced Achilles tendon lesions. Seventy-five rats were divided into five groups (n=15): C- control Sham surgery; I- tendon injury; LA- tendon injury treated with photobiomodulation; AM- tendon injury treated with Amniotic Membrane; LAM- tendon injury + photobiomodulation and Amniotic Membrane, subdivided into three groups (n=5) with analysis at 3, 7, and 14 days. The tendon injuries were made with a 20 g weight released from a mini guillotine onto the ankle in dorsiflexion. AM and LAM groups received an Amniotic Membrane fragment while LA and LAM groups received transcutaneous photobiomodulation, using a 660 nm wavelength laser. The inflammatory cells showed statistical differences between groups C and I (p<0.05), I and AM (p<0.01), I and LA (p<0.05), and I and LAM (p<0.01). Both photobiomodulation and Amniotic Membrane were shown to enhance tendon repair, and the association of photobiomodulation plus Amniotic Membrane was the most effective treatment. We conclude that the association of photobiomodulation plus Amniotic Membrane was effective in accelerating and improving the tendon regeneration process.

Laser light: Illuminating the path to enhanced periodontal care

The utilisation of laser technology in the realm of periodontal care represents a significant advancement in clinical practice. This article delves into the historical context of laser therapy in medicine, from its inception in 1960 to its evolution into low-level laser therapy (LLLT). LLLT, often referred to as photobiomodulation (PBM), has garnered attention due to its potential to enhance periodontal treatment outcomes. The article thoroughly examines the mechanisms of action of photobiomodulation therapy PBM(T), covering its impact on cellular and tissue levels. The authors explore the evidence-based recommendations for the use of PBM(T) in periodontal care, shedding light on its potential to improve periodontal conditions, especially when applied as an adjunct to conventional treatments. They investigate the role of PBM(T) in individuals and its possible contribution to periodontal health. Additionally, the article delves into its application in periodontal regenerative procedures and its ability to expedite soft tissue wound healing and the effects of PBM(T) in reducing periodontal inflammation and mitigating post-periodontal surgery discomfort. In conclusion, the article calls for enhanced clinical research to streamline laser procedures, develop antimicrobial photodynamic therapy, and conduct well-designed randomised controlled trials (RCTs). It also emphasises the importance of understanding the impact of laser therapy on therapeutic and biological goals, the potential to reduce invasive procedures, and the necessity of adequate research funding.

Efficacy of low-level laser therapy in patients with lower extremity tendinopathy or plantar fasciitis: systematic review and meta-analysis of randomised controlled trials

OBJECTIVES

We investigated the effectiveness of low-level laser therapy (LLLT) in lower extremity tendinopathy and plantar fasciitis on patient-reported pain and disability.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Eligible articles in any language were identified through PubMed, Embase and Physiotherapy Evidence Database (PEDro) on the 20 August 2020, references, citations and experts.

ELIGIBILITY CRITERIA FOR SELECTION OF STUDIES

Only randomised controlled trials involving participants with lower extremity tendinopathy or plantar fasciitis treated with LLLT were included.

DATA EXTRACTION AND SYNTHESIS

Random effects meta-analyses with dose subgroups based on the World Association for Laser Therapy treatment recommendations were conducted. Risk of bias was assessed with the PEDro scale.

RESULTS

LLLT was compared with placebo (10 trials), other interventions (5 trials) and as an add-on intervention (3 trials). The study quality was moderate to high.Overall, pain was significantly reduced by LLLT at completed therapy (13.15 mm Visual Analogue Scale (VAS; 95% CI 7.82 to 18.48)) and 4-12 weeks later (12.56 mm VAS (95% CI 5.69 to 19.42)). Overall, disability was significantly reduced by LLLT at completed therapy (Standardised Mean Difference (SMD)=0.39 (95% CI 0.09 to 0.7) and 4-9 weeks later (SMD=0.32 (95% CI 0.05 to 0.59)). Compared with placebo control, the recommended doses significantly reduced pain at completed therapy (14.98 mm VAS (95% CI 3.74 to 26.22)) and 4-8 weeks later (14.00 mm VAS (95% CI 2.81 to 25.19)). The recommended doses significantly reduced pain as an add-on to exercise therapy versus exercise therapy alone at completed therapy (18.15 mm VAS (95% CI 10.55 to 25.76)) and 4-9 weeks later (15.90 mm VAS (95% CI 2.3 to 29.51)). No adverse events were reported.

CONCLUSION

LLLT significantly reduces pain and disability in lower extremity tendinopathy and plantar fasciitis in the short and medium term. Long-term data were not available. Some uncertainty about the effect size remains due to wide CIs and lack of large trials.

PROSPERO REGISTRATION NUMBER

CRD42017077511.

Effectiveness of High Power Laser Therapy on Pain and Isokinetic Peak Torque in Athletes with Proximal Hamstring Tendinopathy: A Randomized Trial

Athletes such as long-distance runners, sprinters, hockey, and/or football players may have proximal hamstring tendinopathy (PHT). Laser therapy has been shown to be effective in tendinopathies. High power laser therapy (HPLT) is used for the treatment of several musculoskeletal conditions; however, its efficacy on PHT has not been investigated. This study is aimed at examining the effects of HPLT on pain and isokinetic peak torque (IPT) in athletes with PHT. The two-arm comparative pretest-posttest experimental design was used with random allocation of 36 athletes aged 18-35 years into two groups (experimental and conventional group). The experimental group included the application of HPLT for 3 weeks. The conventional group included treatment with a conventional physiotherapy program including ultrasound therapy, moist heat pack, and home exercises for a total of 3 weeks. Pain and IPT of the hamstring muscle were measured before and after the application of the intervention. Pain score decreased, and IPT increased significantly (p < 0.05) after application of HPLT, by 61.26% and 13.18%, respectively. In the conventional group, a significant difference (p < 0.05) was observed in pain scores only, which decreased by 41.14%. No significant difference (p > 0.05) was observed in IPT in the conventional group. When HPLT was compared with conventional physiotherapy, a significant difference was found in pain scores only. HPLT for 3 weeks was found to be effective in improving pain in athletes with PHT. However, no significant difference was found between HPLT and conventional physiotherapy (US, moist heat, and home exercises) in improving the IPT of the hamstring muscle.

Allogeneic platelet-derived growth factors local injection in treatment of tennis elbow: a prospective randomized controlled study

PURPOSE

The purpose of this study aimed to evaluate the efficacy of local injection of allogeneic platelet-derived growth factors in treatment of patients with tennis elbow.

PATIENTS AND METHODS

This study included 120 tennis elbow patients randomly divided into two groups. The patients were locally injected with allogeneic growth factors (treatment group) or with normal saline (control group). The outcomes were assessed using Patient-Related Tennis Elbow Evaluation (PRTEE) and quick Disabilities of the Arm, Shoulder and Hand (qDASH) scales. The clinical outcomes were accordingly classified as excellent, good and poor. The patient's satisfaction and adverse effects were also recorded.

RESULTS

There was no statistically significant difference between the two groups regarding the age, gender, dominant arm or the pre-injection scores. At three month follow-up, the reductions in the mean PRTEE and qDASH scores were 88.7% and 70.6% in the treatment group versus 21.8% and 14.9% in the control group, respectively. At the last follow-up, the outcomes in the treatment group were excellent in 85% of patients and good in 15%, versus 8% and 32% in the control group. Overall, 95% were satisfied in the treatment group compared to 25% in control group. Forty patients in the treatment group experienced mild transient post-injection pain.

CONCLUSION

This study strongly suggests that local injection of allogeneic platelet-derived growth factors could be a promising safe treatment option for tennis elbow with significant pain relief, functional improvement and patient's satisfaction. Yet, additional larger studies are needed to assess the durability of these outcomes.

Comparison of the effects of low level laser and insoles on pain, functioning, and muscle strength in subjects with stage 2 posterior tibial tendon dysfunction: A randomized study

BACKGROUND

Low level laser therapy (LLLT) is known to be effective in tendinopathies. No study yet investigated the effect of LLLT on posterior tibial tendon dysfunction (PTTD) in comparison to orthotic treatment.

OBJECTIVE

The aim was to compare the effects of LLLT and insole application on pain, function and muscle strength in subjects with stage 2 PTTD.

METHODS

Fifty-two subjects with stage 2 PTTD were randomly assigned to the LLLT and insole groups. The foot pain, function and strength of invertor and evertor muscles of the subjects was evaluated before and after treatment, and after 9 months.

RESULTS

Significant improvement was observed in the foot function and pain (p< 0.05) in both groups after treatment, but in the 9-month follow-up, the insole group had better values. The increase in 180∘.sec-1 concentric invertor muscle strength was found significant after the treatment and in month-9 as compared to the initial values (p< 0.05).

CONCLUSIONS

Both treatments are effective in reducing treating foot pain, as well as improving the function in subjects with stage 2 PTTD. However, at the end of the 9-month follow-up, it was seen that insoles were more effective. Neither method had a clinically important effect on muscle strength.

The Effectiveness of Laser Acupuncture for Treatment of Musculoskeletal Pain: A Meta-Analysis of Randomized Controlled Studies

Objective

To evaluate the treatment effectiveness of laser acupuncture (LA) in patients with musculoskeletal pain.

Methods

Major electronic databases, including Medline, PubMed, Embase, Cochrane Library, CINAHL, and Scopus were searched to identify double-blind, randomized controlled trials of LA in musculoskeletal disorders. The primary outcome was the treatment efficacy for pain. The secondary outcomes included the comparison of disability, functional impairment, and dropout rate between LA and sham treatment, as well as the effect of sham treatment for pain. The results from included studies were synthesized with the random effects model.

Results

In total, 20 articles comprising 568 patients receiving LA and 534 patients receiving sham treatment were included in the current study. Our analysis showed LA significantly reduced pain (g=0.88, 95% confidence interval [CI]=0.35 to 1.42, p=0.001), disability (g=0.68, 95% CI=0.29 to 1.08, p<0.001), and functional impairment (g=0.67, 95% CI=0.32 to 1.03, p<0.001). Through meta-regression analysis, we found these effects were not moderated by mean age, the percentage of females, or treatment duration. Additionally, there was no significant difference between the two groups in dropout rate (risk ratio=0.73, p=0.08), and the sham treatment significantly reduced only pain intensity (g=0.54, 95% CI=0.32 to 0.77, p<0.001).

Conclusion

Our findings supported that LA significantly reduced pain, disability, and functional impairment in patients with musculoskeletal disorders. Further researches are required to determine the optimal therapeutic parameters and the suitable patients for receiving LA.

Protocol Registration

CRD42020190919.

Efficacy of low-level laser therapy combined with exercise for subacromial impingement syndrome: A randomised controlled trial

OBJECTIVE

To investigate the effect of low-level laser therapy (LLLT) combined with exercise on shoulder pain and disability in patients with subacromial impingement syndrome (SIS).

DESIGN

Randomised controlled trial.

SETTING

Pontifical Catholic University.

SUBJECTS

We enrolled 120 subacromial impingement syndrome patients.

INTERVENTION

Groups I (n = 42), II (n = 42) and III (n = 36) were treated with Low-level laser therapy and exercise, exercise only and Low-level laser therapy only, respectively. Interventions were conducted three times a week for 8 weeks.

MAIN OUTCOME MEASURES

The primary outcome was the change in shoulder pain and disability index (SPADI). Secondary outcomes included changes in the numeric pain rating scale and medication intake.

RESULTS

Average ages of patients in groups I, II and III were 51.9 ± 8.7 years, 56.0 ± 10.4 years and 54.2 ± 7.1 years, respectively. Pain scores at baseline (P = 0.829), 2 months (P = 0.057) and 3 months follow-ups (p = 0.004) were 6.8 (4.7-7.7), 0.2 (0.0-0.5) and 0.3 (0.0-1.0) for group I; 6.6 (5.7-8.0), 0.5 (0.2-2.0) and 0.2 (0.0-3.3) for group II; and 6.5 (5.1-7.4), 2.4 (0.1-6.7) and 4.0 (2.0-5.0) for group III, respectively. SPADI scores at baseline (P = 0.029), 2 months (P < 0.001) and 3 months follow-ups (P = 0.001) were 60.8 (37.7-70.8), 3.8 (0.0-10.8) and 2.3 (0.8-10.8) for group I; 61.5 (41.5-71.5), 9.2 (3.8-29.2) and 14.2 (1.5-38.0) for the group II; and 73.3 (59.2-80.8), 34.2 (16.9-54.6) and 33.1 (22.3-49.2) for the group III, respectively.

CONCLUSION

Low-level laser therapy combined with exercises reduce pain intensity, improve shoulder function and reduces pain intensity and medication intake over 3 months.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02725749.

Immediate effect of photobiomodulation therapy on Achilles tendon morphology and mechanical properties: an exploratory study

Objectives

Evaluate the immediate (within 4 hours) effects of laser-induced photobiomodulation (PBM) therapy on Achilles tendon morphology and mechanical properties in healthy and pathologic tendons.

Materials and Methods

Twenty people with healthy Achilles tendons and twelve people with Achilles tendinopathy participated. One Achilles tendon received PBM treatment following an established protocol and the contralateral side received a placebo treatment. Achilles tendon morphology and mechanical properties were evaluated bilaterally with ultrasound imaging and continuous shear wave elastography immediately before treatment, immediately after treatment, then 2- and 4-hours after treatment.

Results

There were no immediate effects of PBM on tendon morphology or mechanical properties when comparing the PBM-treated side and placebo-treated side within each cohort. Additionally, the effects of PBM did not differ between healthy and pathologic Achilles tendons.

Conclusion

When treated with a laser-induced PBM treatment, healthy and pathologic Achilles tendons do not have immediate (within 4 hours) changes in tendon morphology or mechanical properties. These findings suggest that PBM therapy can be administered before other clinical treatments or high-load activities.

Effectiveness of Low Level Laser Therapy (LLLT) in the treatment of Lateral elbow tendinopathy (LET): an umbrella review

PURPOSE

The aim of this umbrella review is to determine the effectiveness of LLLT in the treatment of LET and to provide recommendations based on this evidence.

METHODS

A comprehensive and systematic review was undertaken using Medline, EBSCO and EMBASE. Systematic reviews or meta-analysis were included if they compared Laser with at least one of the following: (i) placebo, (ii) no treatment, (iii) another treatment, conservative (physical therapy intervention or medical) or operative of LET. Principal outcomes included the assessment of short and long-term effect on functional status, pain, grip strength (pain-free or maximum) and a global measure (overall improvement).

RESULTS

Seven papers met the inclusion criteria for the umbrella review, Five papers were of moderate and two of low methodological quality. All reviews reported benefits associated with laser therapy Vs other intervention or placebo, however the significance of the identified benefits differed between studies and reviews. No review reported negative effects of laser therapy or harm to patients. All reviews noted significant variance between included studies with 2 reviews citing statistically significant heterogeneity. It is essential to consider this in the interpretation of these data.

CONCLUSION

This umbrella review found poor results for the effectiveness of LLLT in the management of LET. Therefore, further research with well-designed RCTs is required to provide meaningful evidence on the effectiveness (absolute and relative) of LLLT for the management of LET.

Comparison of Photobiomodulation and Anti-Inflammatory Drugs on Tissue Repair on Collagenase-Induced Achilles Tendon Inflammation in Rats

BACKGROUND

Tendinopathy is characterized by pain, edema, and structural changes in tendon tissue.

OBJECTIVE

In this animal study we decided to compare the short- and medium-term effects of low-level laser therapy (LLLT), dexamethasone, and diclofenac on inflammation and tendon tissue repair in collagenase-induced tendinitis.

MATERIALS AND METHODS

Two hundred five female Wistar rats were randomly divided into five groups. Animals in the control group were given a saline injection and the experimental groups received a collagenase injection (100 μg/tendon) in the peritendinous Achilles and received no treatment, LLLT (3 J, 810 nm, 100 mW), diclofenac (1.1 mg/kg), or dexamethasone (0.02 mg/kg). Histological analyses were performed at 10 time points up to 60 days (n = 5/group each time point), and included an assessment of the severity of inflammation, collagen fiber content, and organization.

RESULTS

Collagenase injection induced a severe inflammatory reaction with significant reduction in collagen content for 48 h, and disorientation of collagen fibers lasting between 14 and 21 days. Diclofenac and dexamethasone reduced inflammatory signs during the first 2 days, although there was prolongation of the inflammatory phase and slower normalization of tendon quality, particularly in the dexamethasone group. LLLT prevented hemorrhage, reduced inflammation severity, and preserved tendon morphology compared with the other groups.

CONCLUSIONS

LLLT showed a significant superiority over commonly used anti-inflammatory pharmaceutical agents in acute collagenase-induced tendinitis.

A Review of Systematic Reviews of the Effectiveness of Conservative Interventions for Rotator Cuff Tendinopathy

Background

Rotator cuff tendinopathy is common and a wide range of conservative interventions are currently used to treat this problem. The purpose of this review is to systematically review the systematic reviews that evaluate the effectiveness of conservative interventions for rotator cuff tendinopathy.

Methods

An electronic search of PEDro, MEDLINE and the Cochrane Library was undertaken and supplemented by hand and citation searching. The AMSTAR checklist was adopted for quality appraisal and a narrative synthesis was undertaken.

Results

Twenty-six systematic reviews were retrieved. Methodological quality was variable. Exercise and multimodal physiotherapy appear to confer superior outcomes over no treatment or placebo, although the clinical significance of these results remains unclear. Surgery does not confer an additional benefit over exercise alone or multimodal physiotherapy. Combining manual therapy with exercise is not currently supported, neither is the use of corticosteroid injections or acupuncture. Other commonly prescribed interventions lack evidence of effectiveness.

Conclusions

Exercise and multimodal physiotherapy might be effective interventions for rotator cuff tendinopathy, although the clinical significance of this effect is unclear. This interpretation is drawn from systematic reviews comprising mainly small randomized controlled trials that frequently measure outcome in a heterogeneous manner, limiting the strength of any conclusions.

Effect of low-level laser therapy on fracture healing in rabbits

Background and aims

The purpose of this study was to investigate the effect of low-level laser therapy (LLLT) on radial bone fracture gap healing in a rabbit model.

Materials Subjects and Methods

Thirty male white New Zealand rabbits under general anesthesia had a 3mm slice of radial bone surgically removed. Fifteen rabbits were treated by 830 nm laser at 4 J/cm² and 15 were used as non-treated controls. Callus development was assessed by X-ray and radiographs every 7 days for 3 weeks.

Results

Significant radiologic changes were observed in both groups against time (P > 0.001) or from week to week (P > 0.05). However, there was no statistical difference in radiologic scores after week 2 (P = 0.087) or week 3 (P = 0.077) between control and laser treated bone.

Conclusions

Findings suggest that in this study, laser treatment did not enhance callus formation nor reduce repair time of complete fracture of the radius in rabbits.

Low-level laser therapy induces an upregulation of collagen gene expression during the initial process of bone healing: a microarray analysis

This study investigates the histological modifications produced by low level laser therapy (LLLT) on the first day of bone repair, as well as evaluates the LLLT effects on collagen expression on the site of a fracture. Twenty Wistar rats were distributed into a control group (CG) and a laser group (LG). Laser irradiation of Ga-Al-As laser 830 nm, 30 mW, 94 s, 2.8 J was performed in five sessions. Animals were euthanized on day 5 postsurgery. Histopathological analysis showed that LLLT was able to increase deposition of granulation tissue and newly formed bone at the site of the injury. In addition, picrosirius analysis showed that collagen fiber organization in the LG was enhanced compared to CG. Microarray analysis demonstrated that LLLT produced an upregulation type I collagen (COL-I). Immunohistochemical analysis revealed that the subjects that were treated presented a higher immunoexpression of COL-I. Our findings indicated that LLLT improves bone healing by producing a significant increase in the expression of collagen genes.

Low-level laser therapy attenuates the acute inflammatory response induced by muscle traumatic injury

The purpose of this work was to investigate the effect of early and long-term low-level laser therapy (LLLT) on oxidative stress and inflammatory biomarkers after acute-traumatic muscle injury in Wistar rats. Animals were randomly divided into the following four groups: control group (CG), muscle injury group (IG), CG + LLLT, and IG + LLLT: laser treatment with doses of 3 and 5 J/cm(2). Muscle traumatic injury was induced by a single-impact blunt trauma in the rat gastrocnemius. Irradiation for 3 or 5 J/cm(2) was initiated 2, 12, and 24 h after muscle trauma induction, and the treatment was continued for five consecutive days. All the oxidant markers investigated. namely thiobarbituric acid-reactive substance, carbonyl, superoxide dismutase, glutathione peroxidase, and catalase, were increased as soon as 2 h after muscle injury and remained increased up to 24 h. These alterations were prevented by LLLT at a 3 J/cm(2) dose given 2 h after the trauma. Similarly, LLLT prevented the trauma-induced proinflammatory state characterized by IL-6 and IL-10. In parallel, trauma-induced reduction in BDNF and VEGF, vascular remodeling and fiber-proliferating markers, was prevented by laser irradiation. In order to test whether the preventive effect of LLLT was also reflected in muscle functionality, we tested the locomotor activity, by measuring distance traveled and the number of rearings in the open field test. LLLT was effective in recovering the normal locomotion, indicating that the irradiation induced biostimulatory effects that accelerated or resolved the acute inflammatory response as well as the oxidant state elicited by the muscle trauma.

Short-term effects of high-intensity laser therapy on frozen shoulder: A prospective randomized control study

BACKGROUND

Frozen shoulder, which is characterized by shoulder pain and limitation of the range of motion (ROM), is a common disorder. High-intensity laser therapy (HILT) was recently introduced in the musculoskeletal therapeutic field.

OBJECTIVE

The objective of this study is to evaluate the clinical efficacy of HILT in patients with frozen shoulder.

DESIGN

A prospective randomized controlled study.

METHOD

Patients with frozen shoulder were randomly divided into 2 groups: a HILT group (n = 33) and a placebo group (n = 33). The treatment was administered 3 times per week on alternate days for 3 weeks. For all patients, the visual analog scale (VAS) for pain, VAS for satisfaction, and passive ROM were measured at baseline and 3, 8, and 12 weeks after the treatment.

RESULTS

The HILT group had a lower pain VAS score at 3 weeks (3.2 ± 1.7 vs. 4.3 ± 2.2, p = 0.033) and 8 weeks (2.2 ± 2.0 vs. 3.4 ± 2.7, p = 0.042), however, no statistically significant difference in the pain VAS was observed between the two groups at the final follow-up (12 weeks). No statistical difference in the ROM and the satisfaction VAS was observed between the 2 groups at serial follow-ups.

CONCLUSIONS

In management of frozen shoulder, HILT provided significant pain relief at 3 and 8 weeks, but not at the final follow-up time point. HILT is a noninvasive adjuvant treatment that can reduce pain in frozen shoulders. Further study is needed in order to optimize the dose and duration of HILT.

The Effect of Three Desensitizing Agents on Dentin Hypersensitivity: A Randomized, Split-mouth Clinical Trial

The aim of this study was to evaluate the efficacy of three desensitizing agents to provide relief to dentin hypersensitivity after one session in a four-week follow-up. Forty selected patients participated in a double-blind study following a split-mouth model. One application of the desensitizing agents (A, Admira Protect [Voco]; B, Bifluorid 12 [Voco]; and C, Colgate Pro-Relief in office [Colgate Palmolive]) was performed in three different quadrants for each patient. Each tooth was evaluated by tactile and evaporative stimuli, and the sensitivity response was measured using the Visual Analogue Scale. Evaluations were performed at baseline, immediately after treatment, and after one, two, three, and four weeks. The application of Kruskal-Wallis and Dunn multiple comparisons tests (5%) for both tactile and evaporative stimuli showed that all agents presented a significant desensitizing effect. In groups A and B this relief was maintained for four and three weeks, respectively, as measured by tactile stimulus and for four weeks with evaporative stimulus. The desensitizing effect for group C was maintained for two weeks for both tactile and evaporative stimuli. It is concluded that all desensitizing agents tested were effective in reducing sensitivity compared to baseline values. One application of Admira Protect and Bifluorid 12 presented a longer-lasting desensitizing effect than did Colgate Pro-Relief (applied in the office) on both tactile and evaporative stimuli.

Low-level laser therapy in IL-1β, COX-2, and PGE2 modulation in partially injured Achilles tendon

This study evaluated IL-1β, COX-2, and PGE2 modulation in partially injured Achilles tendons treated with low-level laser therapy (LLLT). Sixty-five male Wistar rats were used. Sixty were submitted to a direct injury on Achilles tendon and then distributed into six groups: LASER 1 (a single LLLT application), LASER 3 (three LLLT applications), and LASER 7 (seven LLLT applications) and Sham 1, 3, and 7 (the same injury but LLLT applications were simulated). The five remaining animals were allocated at control group (no procedure performed). LLLT (780 nm) was applied with 70 mW of mean power and 17.5 J/cm(2) of fluency for 10 s, once a day. The tendons were surgically removed and assessed immunohistochemically for IL-1β, COX-2, and PGE2. In comparisons with control (IL-1β: 100.5 ± 92.5 / COX-2: 180.1 ± 97.1 / PGE2: 187.8 ± 128.8) IL-1β exhibited (mean ± SD) near-normal level (p > 0.05) at LASER 3 (142.0 ± 162.4). COX-2 and PGE2 exhibited near-normal levels (p > 0.05) at LASER 3 (COX-2: 176.9 ± 75.4 / PGE2: 297.2 ± 259.6) and LASER 7 (COX-2: 259.2 ± 190.4 / PGE2: 587.1 ± 409.7). LLLT decreased Achilles tendon's inflammatory process.

Effects of laser treatment on the expression of cytosolic proteins in the synovium of patients with osteoarthritis

BACKGROUND AND OBJECTIVE

Low level laser therapy (LLLT) has been developed for non-invasive treatment of joint diseases. We have previously shown that LLLT influenced synovial protein expression in rheumatoid arthritis (RA). The aim of this study was to assess the effects of laser irradiation on osteoarthritic (OA) synovial protein expression.

STUDY DESIGN/MATERIALS AND METHODS

The synovial membrane samples removed from the knees of 6 OA patients were irradiated ex vivo using near infrared diode laser (807-811 nm; 25 J/cm(2) ). An untreated sample taken from the same patient served as control. Synovial protein separation and identification were performed by two-dimensional differential gel electrophoresis and mass spectrometry, respectively.

RESULTS

Eleven proteins showing altered expression due to laser irradiation were identified. There were three patients whose tissue samples demonstrated a significant increase (P < 0.05) in mitochondrial heat shock 60 kD protein 1 variant 1. The expression of the other proteins (calpain small subunit 1, tubulin alpha-1C and beta 2, vimentin variant 3, annexin A1, annexin A5, cofilin 1, transgelin, and collagen type VI alpha 2 chain precursor) significantly decreased (P < 0.05) compared to the control samples.

CONCLUSIONS

A single diode laser irradiation of the synovial samples of patients with osteoarthritis can statistically significantly alter the expression of some proteins in vitro. These findings provide some more evidence for biological efficacy of LLLT treatment, used for osteoarthritis.

Low-level laser irradiation stimulates tenocyte proliferation in association with increased NO synthesis and upregulation of PCNA and cyclins

Low-level laser therapy is commonly used to treat tendinopathy or tendon injury. Tendon healing requires tenocyte migration to the repair site, followed by proliferation and synthesis of the extracellular matrix. There are few evidence to elucidate that low-level laser promote tenocyte proliferation. This study was designed to determine the effect of laser on tenocyte proliferation. Furthermore, the association of this effect with secretion of nitric oxide (NO) and the expressions of proliferating cell nuclear antigen (PCNA) and cyclins D1, E, A, and B1 was investigated. Tenocytes intrinsic to rat Achilles tendon were treated with low-level laser (660 nm). Tenocyte proliferation was evaluated by MTT assay and immunocytochemistry with Ki-67 stain. NO in the conditioned medium was measured by ELISA. Western blot analysis was used to evaluate the protein expressions of PCNA and cyclins D1, E, A, and B1. The results revealed that tenocytes proliferation was enhanced dose dependently by laser. NO secretion was increased after laser treatment. PCNA and cyclins E, A, and B1 were upregulated by laser. In conclusion, low-level laser irradiation stimulates tenocyte proliferation in a process that is mediated by upregulation of NO, PCNA, and cyclins E, A, and B1.

Platelet rich plasma versus laser therapy in lateral epicondylitis of elbow

BACKGROUND

Platelet rich plasma (PRP) extract has shown to be a general stimulation for repair and currently used widely in various sports injury. A prospective observational study was done to assess the efficacy of autologous PRP injection in lateral epicondylitis of elbow, and compare the result with low level laser therapy.

MATERIALS AND METHODS

The trial was conducted at a tertiary care center for a period of 2 years. Eighty-one patients with chronic lateral epicondylitis were divided into two groups. PRP group (n = 39) and laser therapy group (n = 42). The primary analysis included Nirschl pain score, local tenderness, pain on wrist extension, grip strength, elbow swelling were clinically assessed at different interval of followup (minimum followup: 52 weeks) and; clinical and functional outcome evaluated at final followup. The statistical analysis were done.

RESULTS

The mean Nirschl pain score decreased significantly from baseline in PRP when compared with low level laser therapy (P ≤ 0.05).

CONCLUSIONS

Treatment of patients with chronic lateral epicondylitis with PRP extract reduced pain and significantly increased function, exceeding the effect of low level laser therapy on long term followup. Low-level laser therapy is better in the short term period, but on long term followup injection PRP therapy is better than laser therapy in lateral epicondylitis.

CHELT therapy in the treatment of chronic insertional Achilles tendinopathy

The application of laser therapy on soft tissue is used for pain relief, anti-inflammation action and biostimulation. The efficiency of High Energy Laser Therapy has not yet been studied on Achilles tendinopathy. The aim of the study is to evaluate the effectiveness of a flow of Cold air and High Energy Laser Therapy (CHELT) versus Extracorporeal Shock Waves Therapy (ESWT) in the treatment of Achilles tendinopathy. In this prospective, clinical trial, 60 subjects affected by insertional Achilles tendinopathy were enrolled and randomized to CHELT (30 subjects) or to ESWT (30 subjects). In CHELT group the patients received ten daily sessions of 1,200 J and 12 W of laser therapy (wavelength of 1,084, 810 and 980 nm) added to a flow of cold air at -30 °C. In the ESWT group, the patients received three sessions at 3- to 4-day intervals of 1,600 impulses with an energy flux density (EFD) of 0.05-0.07 mJ/mm(2). Both groups of participants performed stretching and eccentric exercises over a 2-month period. The visual analogue scale (VAS), the Ankle-Hindfoot Scale, and the Roles and Maudsley Score were measured before treatment (T0), and at end of the treatment session (T1) and 2 (T2) and 6 months (T3) after treatment during the follow-up examinations. In both groups, we found a statistically significant improvement of the VAS at T1, T2 and T3 (p < 0.01). The difference between the two groups was statistically significant in favour of the CHELT group (p < 0.001). At 2 months, the CHELT group was statistically better for Ankle-Hindfoot Scale and the Roles and Maudsley Score (p < 0.05) and at 6 months only for the Roles and Maudsley Score (p < 0.001). High Energy Laser Therapy gave quicker and better pain relief. It also gave the patient a full functional recovery and greater satisfaction.

A pilot study into the effect of low-level laser therapy in patients with chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a common inflammatory disease of the nose and paranasal sinuses that has a significant impact on patients' quality of life. No study has examined the effectiveness of applying low-level laser therapy (LLLT) locally over the sinuses in patients with CRS. The aim of this study was to evaluate the effect of LLLT in patients with CRS. Fifteen adult patients with CRS participated in this pilot pretest-posttest clinical study. Patients were treated with a 830-nm Ga-Al-As laser in continuous-wave mode at a power output of 30 mW and energy dose of 1 J. Laser irradiation was delivered on six points over each maxillary or frontal sinus with 33 sec irradiation for each point and a total treatment duration of 198 sec for each sinus. Patients were given LLLT three times per week for ten treatment sessions. Patients were asked to score their symptoms in accordance with a four-point scale (0-3), and a total symptom score (TSS) for each patient was calculated. Percentage improvement of TSS was considered as the primary outcome measure. TSS was calculated at baseline (T0), at 2 weeks (T1) and at 4 weeks (T2). The TSS was improved significantly at T1 (39%) and at T2 (46.34%). A large effect size for LLLT was found (ηp(2) ηp(2)  =  0.63). The therapeutic effect was sustained for a mean of 5 months. This pilot study indicates that LLLT applied for 4 weeks improves symptoms in patients with CRS.

Efeitos local e sistêmico do laser de baixa potência no limiar de dor por pressão em indivíduos saudáveis

O laser de baixa potência é utilizado como recurso terapêutico para controle da dor. Porém, ainda é questionado o real efeito como também a dosimetria mais eficaz para esse efeito analgésico. Assim, este estudo teve como objetivo avaliar os efeitos local e sistêmico do laser de baixa potência no limiar de dor por pressão, em indivíduos saudáveis. Cento e cinquenta indivíduos foram distribuídos aleatoriamente em cinco grupos: Controle, Laser Placebo, 3 J, 6 J e 12 J. Para avaliar o limiar de dor, utilizou-se um algômetro de pressão em cinco tempos distintos. Na região da mão dominante do indivíduo, foi realizado o laser e a algometria para verificar o efeito local. Já naquela da perna dominante, realizou-se somente a algometria para verificar efeito sistêmico do laser de baixa potência. Houve redução local do limiar de dor por pressão no Grupo 3 J em comparação com os grupos Controle (p=0,0016) e Placebo (p=0,004), e não houve alteração sistêmica do limiar de dor por pressão. O laser de baixa potência, quando utilizado com energia de 3 J, reduziu o limiar de dor por pressão local em indivíduos saudáveis, porém não houve alteração sistêmica.

Skin penetration time-profiles for continuous 810 nm and Superpulsed 904 nm lasers in a rat model

OBJECTIVE

The purpose of this study was to investigate the rat skin penetration abilities of two commercially available low-level laser therapy (LLLT) devices during 150 sec of irradiation.

BACKGROUND DATA

Effective LLLT irradiation typically lasts from 20 sec up to a few minutes, but the LLLT time-profiles for skin penetration of light energy have not yet been investigated.

MATERIALS AND METHODS

Sixty-two skin flaps overlaying rat's gastrocnemius muscles were harvested and immediately irradiated with LLLT devices. Irradiation was performed either with a 810 nm, 200 mW continuous wave laser, or with a 904 nm, 60 mW superpulsed laser, and the amount of penetrating light energy was measured by an optical power meter and registered at seven time points (range, 1-150 sec).

RESULTS

With the continuous wave 810 nm laser probe in skin contact, the amount of penetrating light energy was stable at ∼20% (SEM±0.6) of the initial optical output during 150 sec irradiation. However, irradiation with the superpulsed 904 nm, 60 mW laser showed a linear increase in penetrating energy from 38% (SEM±1.4) to 58% (SEM±3.5) during 150 sec of exposure. The skin penetration abilities were significantly different (p<0.01) between the two lasers at all measured time points.

CONCLUSIONS

LLLT irradiation through rat skin leaves sufficient subdermal light energy to influence pathological processes and tissue repair. The finding that superpulsed 904 nm LLLT light energy penetrates 2-3 easier through the rat skin barrier than 810 nm continuous wave LLLT, corresponds well with results of LLLT dose analyses in systematic reviews of LLLT in musculoskeletal disorders. This may explain why the differentiation between these laser types has been needed in the clinical dosage recommendations of World Association for Laser Therapy.

Low-level laser therapy in the prevention and treatment of cancer therapy-induced mucositis: 2012 state of the art based on literature review and meta-analysis

PURPOSE OF REVIEW

To discuss the promising state of the art low-level laser therapy (LLLT) for preventive and therapeutic usage in oral mucositis due to cancer therapy.

RECENT FINDINGS

Photomedicine using LLLT is very effective with intraoral and extraoral devices in the management of oral mucositis, based on several studies including randomized control studies. A systematic review identified 33 relevant articles that were subjected to meta-analysis based on which laser parameters in routine practice are being defined. Meta-analysis showed that LLLT reduced risk of oral mucositis with relative risk (RR) 2.45 [confidence interval (CI) 1.85-3.18], reduced duration, severity of oral mucositis and reduced number of days with oral mucositis (4.38 days, P = 0.0009). RR was similar between the red (630-670 nm) and infrared (780-830 nm) LLLT. Pain-relieving effect based on the Cohen scale was at 1.22 (CI 0.19-2.25).

SUMMARY

No adverse side effects of LLLT were reported; hence, we recommend red or infrared LLLT with diode output between 10-100 mW, dose of 2-3 J/cm2/cm2 for prophylaxis and 4 J/cm2 (maximum limit) for therapeutic effect, application on single spot rather than scanning motion. Lesions must be evaluated by a trained clinician and therapy should be repeated daily or every other day or a minimum of three times per week until resolution. There is moderate-to-strong evidence in favor of LLLT at optimal doses as a well tolerated, relatively inexpensive intervention for cancer therapy-induced oral mucositis. It is envisaged that LLLT will soon become part of routine oral supportive care in cancer.

Clinical effectiveness of low-level laser therapy as an adjunct to eccentric exercise for the treatment of Achilles' tendinopathy: a randomized controlled trial

OBJECTIVE

To investigate the effectiveness of low-level laser therapy (LLLT) as an adjunct to a program of eccentric exercises for the treatment of Achilles' tendinopathy.

DESIGN

Randomized controlled trial with evaluations at baseline and 4, 12, and 52 weeks.

SETTING

Primary care clinic.

PARTICIPANTS

Participants with midportion Achilles' tendinopathy were randomly assigned to 2 groups (LLLT n=20: mean age ± SD, 45.6±9.1y; placebo n=20: mean age ± SD, 46.5±6.4y). The 12-week evaluation was completed by 36 participants (90%), and 33 participants (82.5%) completed the 52-week evaluation.

INTERVENTION

Both groups of participants performed eccentric exercises over a 3-month period. In addition, they received either an active or placebo application of LLLT 3 times per week for the first 4 weeks; the dose was 3J per point.

MAIN OUTCOME MEASURES

The primary outcome was the Victorian Institute of Sport Assessment-Achilles' questionnaire (VISA-A) score at 12 weeks; secondary outcome was a visual analog scale for pain. Outcomes were measured at baseline and 4, 12, and 52 weeks.

RESULTS

Baseline characteristics exhibited no differences between groups. At the primary outcome point, there was no statistically significant difference in VISA-A scores between groups (P>.05). The difference in VISA-A scores at the 4-week point significantly favored the placebo group (F(1)=6.411, sum of squares 783.839; P=.016); all other outcome scores showed no significant difference between the groups at any time point. Observers were blinded to groupings.

CONCLUSIONS

The clinical effectiveness of adding LLLT to eccentric exercises for the treatment of Achilles' tendinopathy has not been demonstrated using the parameters in this study.

Low-level laser irradiation stimulates tenocyte migration with up-regulation of dynamin II expression

Low-level laser therapy (LLLT) is commonly used to treat sports-related tendinopathy or tendon injury. Tendon healing requires tenocyte migration to the repair site, followed by proliferation and synthesis of the extracellular matrix. This study was designed to determine the effect of laser on tenocyte migration. Furthermore, the correlation between this effect and expression of dynamin 2, a positive regulator of cell motility, was also investigated. Tenocytes intrinsic to rat Achilles tendon were treated with low-level laser (660 nm with energy density at 1.0, 1.5, and 2.0 J/cm²). Tenocyte migration was evaluated by an in vitro wound healing model and by transwell filter migration assay. The messenger RNA (mRNA) and protein expressions of dynamin 2 were determined by reverse transcription/real-time polymerase chain reaction (real-time PCR) and Western blot analysis respectively. Immunofluorescence staining was used to evaluate the dynamin 2 expression in tenocytes. Tenocytes with or without laser irradiation was treated with dynasore, a dynamin competitor and then underwent transwell filter migration assay. In vitro wound model revealed that more tenocytes with laser irradiation migrated across the wound border to the cell-free zone. Transwell filter migration assay confirmed that tenocyte migration was enhanced dose-dependently by laser. Real-time PCR and Western-blot analysis demonstrated that mRNA and protein expressions of dynamin 2 were up-regulated by laser irradiation dose-dependently. Confocal microscopy showed that laser enhanced the expression of dynamin 2 in cytoplasm of tenocytes. The stimulation effect of laser on tenocytes migration was suppressed by dynasore. In conclusion, low-level laser irradiation stimulates tenocyte migration in a process that is mediated by up-regulation of dynamin 2, which can be suppressed by dynasore.

Infrared (810 nm) low-level laser therapy in rat achilles tendinitis: a consistent alternative to drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used and can reduce musculoskeletal pain in spite of the cost of adverse reactions like gastrointestinal ulcers or cardiovascular events. The current study investigates if a safer treatment such as low-level laser therapy (LLLT) could reduce tendinitis inflammation, and whether a possible pathway could be through inhibition of either of the two-cyclooxygenase (COX) isoforms in inflammation. Wistar rats (six animals per group) were injected with saline (control) or collagenase in their Achilles tendons. Then, we treated them with three different doses of IR LLLT (810 nm; 100 mW; 10 s, 30 s and 60 s; 3.57 W cm(-2); 1 J, 3 J, 6 J) at the sites of the injections, or intramuscular diclofenac, a nonselective COX inhibitor/NSAID. We found that LLLT dose of 3 J significantly reduced inflammation through less COX-2-derived gene expression and PGE(2) production, and less edema formation compared to nonirradiated controls. Diclofenac controls exhibited significantly lower PGE(2) cytokine levels at 6 h than collagenase control, but COX isoform 1-derived gene expression and cytokine PGE(2) levels were not affected by treatments. As LLLT seems to act on inflammation through a selective inhibition of the COX-2 isoform in collagenase-induced tendinitis, LLLT may have potential to become a new and safer nondrug alternative to coxibs.

Efficacy of low-level laser therapy in the management of neck pain: a systematic review and meta-analysis of randomised placebo or active-treatment controlled trials

BACKGROUND

Neck pain is a common and costly condition for which pharmacological management has limited evidence of efficacy and side-effects. Low-level laser therapy (LLLT) is a relatively uncommon, non-invasive treatment for neck pain, in which non-thermal laser irradiation is applied to sites of pain. We did a systematic review and meta-analysis of randomised controlled trials to assess the efficacy of LLLT in neck pain.

METHODS

We searched computerised databases comparing efficacy of LLLT using any wavelength with placebo or with active control in acute or chronic neck pain. Effect size for the primary outcome, pain intensity, was defined as a pooled estimate of mean difference in change in mm on 100 mm visual analogue scale.

FINDINGS

We identified 16 randomised controlled trials including a total of 820 patients. In acute neck pain, results of two trials showed a relative risk (RR) of 1.69 (95% CI 1.22-2.33) for pain improvement of LLLT versus placebo. Five trials of chronic neck pain reporting categorical data showed an RR for pain improvement of 4.05 (2.74-5.98) of LLLT. Patients in 11 trials reporting changes in visual analogue scale had pain intensity reduced by 19.86 mm (10.04-29.68). Seven trials provided follow-up data for 1-22 weeks after completion of treatment, with short-term pain relief persisting in the medium term with a reduction of 22.07 mm (17.42-26.72). Side-effects from LLLT were mild and not different from those of placebo.

INTERPRETATION

We show that LLLT reduces pain immediately after treatment in acute neck pain and up to 22 weeks after completion of treatment in patients with chronic neck pain.

FUNDING

None.

Some conservative strategies are effective when added to controlled mobilisation with external support after acute ankle sprain: a systematic review

QUESTIONS

Which intervention(s) best augment early mobilisation and external support after an acute ankle sprain? What is the most appropriate method of preventing re-injury?

DESIGN

A systematic review of randomised controlled trials published from 1993 to April 2005.

PARTICIPANTS

People with an acute ankle sprain.

INTERVENTION

Any pharmacological, physiotherapeutic, complementary or electrotherapeutic intervention added to controlled mobilisation with external support. Immobilisation, surgical intervention, and use of external ankle supports in isolation were excluded.

OUTCOMES

Pain, function, swelling, re-injury, and global improvement; assessed at short, intermediate, and long-term follow-up.

RESULTS

23 trials were included with a mean PEDro score of 6/10. There was strong evidence that non-steroidal anti-inflammatory drugs can reduce pain and improve short-term ankle function. There was moderate evidence that neuromuscular training decreases functional instability and minimises re-injury; and that comfrey root ointment decreases pain and improves function. There was also moderate evidence that manual therapy techniques improve ankle dorsiflexion. There was no evidence to support the use of electrophysical agents or hyperbaric oxygen therapy. Very few long-term follow-ups were undertaken, and few studies focused on preventing long-term morbidity.

CONCLUSIONS

Non-steroidal anti-inflammatory drugs, comfrey root ointment, and manual therapy can significantly improve short-term symptoms after ankle sprain, and neuromuscular training may prevent re-injury. More high quality studies are needed to develop evidence-based guidelines on ankle rehabilitation beyond the acute phases of injury management.

A systematic review with procedural assessments and meta-analysis of low level laser therapy in lateral elbow tendinopathy (tennis elbow)

Background

Recent reviews have indicated that low level level laser therapy (LLLT) is ineffective in lateral elbow tendinopathy (LET) without assessing validity of treatment procedures and doses or the influence of prior steroid injections.

Methods

Systematic review with meta-analysis, with primary outcome measures of pain relief and/or global improvement and subgroup analyses of methodological quality, wavelengths and treatment procedures.

Results

18 randomised placebo-controlled trials (RCTs) were identified with 13 RCTs (730 patients) meeting the criteria for meta-analysis. 12 RCTs satisfied half or more of the methodological criteria. Publication bias was detected by Egger's graphical test, which showed a negative direction of bias. Ten of the trials included patients with poor prognosis caused by failed steroid injections or other treatment failures, or long symptom duration or severe baseline pain. The weighted mean difference (WMD) for pain relief was 10.2 mm [95% CI: 3.0 to 17.5] and the RR for global improvement was 1.36 [1.16 to 1.60]. Trials which targeted acupuncture points reported negative results, as did trials with wavelengths 820, 830 and 1064 nm. In a subgroup of five trials with 904 nm lasers and one trial with 632 nm wavelength where the lateral elbow tendon insertions were directly irradiated, WMD for pain relief was 17.2 mm [95% CI: 8.5 to 25.9] and 14.0 mm [95% CI: 7.4 to 20.6] respectively, while RR for global pain improvement was only reported for 904 nm at 1.53 [95% CI: 1.28 to 1.83]. LLLT doses in this subgroup ranged between 0.5 and 7.2 Joules. Secondary outcome measures of painfree grip strength, pain pressure threshold, sick leave and follow-up data from 3 to 8 weeks after the end of treatment, showed consistently significant results in favour of the same LLLT subgroup (p < 0.02). No serious side-effects were reported.

Conclusion

LLLT administered with optimal doses of 904 nm and possibly 632 nm wavelengths directly to the lateral elbow tendon insertions, seem to offer short-term pain relief and less disability in LET, both alone and in conjunction with an exercise regimen. This finding contradicts the conclusions of previous reviews which failed to assess treatment procedures, wavelengths and optimal doses.

Effects of low-level laser therapy and eccentric exercises in the treatment of recreational athletes with chronic achilles tendinopathy

BACKGROUND

Eccentric exercises (EEs) are recommended for the treatment of Achilles tendinopathy, but the clinical effect from EE has a slow onset.

HYPOTHESIS

The addition of low-level laser therapy (LLLT) to EE may cause more rapid clinical improvement.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 52 recreational athletes with chronic Achilles tendinopathy symptoms were randomized to groups receiving either EE + LLLT or EE + placebo LLLT over 8 weeks in a blinded manner. Low-level laser therapy (lambda = 820 nm) was administered in 12 sessions by irradiating 6 points along the Achilles tendon with a power density of 60 mW/cm(2) and a total dose of 5.4 J per session.

RESULTS

The results of the intention-to-treat analysis for the primary outcome, pain intensity during physical activity on the 100-mm visual analog scale, were significantly lower in the LLLT group than in the placebo LLLT group, with 53.6 mm versus 71.5 mm (P = .0003) at 4 weeks, 37.3 mm versus 62.8 mm (P = .0002) at 8 weeks, and 33.0 mm versus 53.0 mm (P = .007) at 12 weeks after randomization. Secondary outcomes of morning stiffness, active dorsiflexion, palpation tenderness, and crepitation showed the same pattern in favor of the LLLT group.

CONCLUSION

Low-level laser therapy, with the parameters used in this study, accelerates clinical recovery from chronic Achilles tendinopathy when added to an EE regimen. For the LLLT group, the results at 4 weeks were similar to the placebo LLLT group results after 12 weeks.

Low-Level Laser Therapy (GaAs λ = 904 nm) Reduces Inflammatory Cell Migration in Mice with Lipopolysaccharide-Induced Peritonitis

OBJECTIVE

This study was designed to study the effect of an infrared low-level laser (GaAs lambda = 904 nm, 4 mW) on inflammatory cell migration in lipopolysaccharide (LPS)-induced peritonitis in mice.

BACKGROUND DATA

It has been suggested that red wavelengths of low-level laser therapy (LLLT) can exert anti-inflammatory effects, but little is known about the anti-inflammatory effects of infrared lasers. Peritonitis is a potentially life-threatening inflammatory condition that may be suitable for studying anti-inflammatory effects of infrared lasers.

METHODS

Sixty male mice were randomly divided into five groups, and one group was given an intraperitoneal sterile saline injection. In the remaining four groups, peritonitis was induced by an intraperitoneal LPS injection. Animals in three of the LPS groups were irradiated at a single point over the peritoneum with doses of 3 J/cm(2), 7.5 J/cm(2), and 15 J/cm(2), respectively. The fourth group injected with LPS was an LPS-control group.

RESULTS

At 6 hours after injection the groups irradiated with doses of 3 J/cm(2) and 7.5 J/cm(2) had a reduced number of neutrophil cells in the peritoneal cavity compared with the LPS-control group, and there were significant differences between the number of neutrophils in the peritoneal cavity between the LPS-control group and groups irradiated with doses of 3 J/cm(2) (-42%) and 7.5 J/cm(2) (-70%). In the group irradiated with 15 J/cm(2), neutrophil cell counts were lower than, but not significantly different from, LPS controls (-38%; p = 0.07). At 24 hours after injection, both neutrophil and total leukocyte cell counts were lower in all the irradiated groups than in the LPS controls. The 3-J/cm(2) exposure group showed the best results at 24 hours, with reductions of 77% in neutrophil and 49% in leukocyte counts.

CONCLUSION

Low-level laser therapy (904 nm) can reduce inflammatory cell migration in mice with LPS-induced peritonitis in a dose-dependent manner.