Low Reactive-level Laser Therapy Research Articles

Effects of Irradiation by Carbon Dioxide Laser Equipped With a Water Spray Function on Bone Formation in Rat Tibiae.

Irradiation of tissue with carbon dioxide (CO2) laser shows a characteristic thermal effect that causes vaporization of tissue in the target region. However, the thermal effect in places other than the target region induces tissue damage. Two methods are used: high reactive-level laser therapy (HLLT), aimed at surgical treatment, and low reactive-level laser therapy (LLLT), aimed at cell and tissue activation. In both, vaporization of tissue is induced by thermal damage. A water spray function may ameliorate thermal damage from CO2 laser irradiation. In this study, we irradiated CO2 laser on rat tibiae with or without a water spray function and examined the effects of this technique on bone metabolism. Bone defects were created in rat tibiae by dental bur in a Bur group and by laser in laser irradiation groups with (Spray group) and without (Air group) water spray function. At 1 week postoperatively, histological analyses of tibiae were performed using hematoxylin and eosin staining, immunohistochemical staining (IHC) with anti-sclerostin antibody, and 3-dimensional (3D) observation using micro-computed tomography. Histological findings and 3D observation confirmed induction of new bone formation following laser irradiation in both the Air and Spray groups. No bone formation was seen in the Bur group. IHC revealed that the activity of osteocytes in the region of irradiated cortical bone was markedly impaired in the Air group, but osteocyte impairment was ameliorated in the Spray group and absent in the Bur group. The water spray function appears effective in reducing thermal damage to tissues irradiated by CO2 laser. CO2 lasers with water spray function may be useful in bone regeneration therapy.

Chronological Gene Expression of Human Gingival Fibroblasts with Low Reactive Level Laser (LLL) Irradiation.

Though previously studies have reported that Low reactive Level Laser Therapy (LLLT) promotes wound healing, molecular level evidence was uncleared. The purpose of this study is to examine the temporal molecular processes of human immortalized gingival fibroblasts (HGF) by LLLT by the comprehensive analysis of gene expression. HGF was seeded, cultured for 24 h, and then irradiated with a Nd: YAG laser at 0.5 W for 30 s. After that, gene differential expression analysis and functional analysis were performed with DNA microarray at 1, 3, 6 and 12 h after the irradiation. The number of genes with up- and downregulated differentially expression genes (DEGs) compared to the nonirradiated group was large at 6 and 12 h after the irradiation. From the functional analysis results of DEGs, Biological Process (BP) based Gene Ontology (GO), BP ‘the defense response’ is considered to be an important process with DAVID. Additionally, the results of PPI analysis of DEGs involved in the defense response with STRING, we found that the upregulated DEGs such as CXCL8 and NFKB1, and the downregulated DEGs such as NFKBIA and STAT1 were correlated with multiple genes. We estimate that these genes are key genes on the defense response after LLLT.

The Effect on Muscle Hardness of Acupuncture Stimulation Using Low-reactive Level Laser Therapy and Silver Spike Point Therapy, along with Stretching.

Muscle hardness causes lower activity in athletic practice or sport competition. Increase in muscle hardness often cause injury and muscle fatigue. The aim of this study is to investigate the effect on muscle hardness of acupuncture stimulation using low-reactive level laser therapy (LLLT) and silver spike point (SSP) therapy, along with stimulation by stretching. Muscle fatigue was created experimentally, and the effect of LLLT was examined with the indices of muscle hardness and the pennation angle, using ultrasound diagnostic equipment with real-time tissue elastography (RTE) functionality. As a result, a combined use of stretching and SSP therapy was effective on muscle hardness, while LLLT alone had no immediate lowering of muscle hardness. In addition, only the laser stretching group demonstrated a significant decrease in the pennation angle. This is because an improved local blood flow due to SSP therapy is considered to have relaxed muscle tonus, which boosted metabolism and removed algogenic substances. This became more effective through a combined use of stretching and low-power laser irradiation. Moreover, it was suggested that stimulation of the acupuncture points in the crus could have a further effect on muscle hardness and the pennation angle.

Effects of Low Reactive Level Laser Therapy on the Progress of Bone Healing

Effects of Low Reactive Level Laser Therapy on the Progress of Bone Healing

Promotion of Tissue Healing and Regeneration with Low-Reactive Level Laser Therapy Using Diode Lasers in Dental Field: Review of Basic and Clinical Research

Promotion of Tissue Healing and Regeneration with Low-Reactive Level Laser Therapy Using Diode Lasers in Dental Field: Review of Basic and Clinical Research

Low Reactive Level Laser Therapy (LLLT) for Sports Injury

Low Reactive Level Laser Therapy (LLLT) for Sports Injury

Wound healing efficacy of a 660-nm diode laser in a rat incisional wound model.

This study aimed to elucidate the optimum usage parameters of low reactive-level laser therapy (LLLT) in a rat incisional wound model. In Sprague-Dawley rats, surgical wounds of 15-mm length were made in the dorsal thoracic region. They were divided into groups to receive 660-nm diode laser irradiation 24h after surgery at an energy density of 0 (control), 1, 5, or 10J/cm2. Tissue sections collected on postoperative day 3 were stained with hematoxylin-eosin and an antibody for ED1 to determine the number of macrophages around the wound. Samples collected on day 7 were stained with hematoxylin-eosin and observed via polarized light microscopy to measure the area occupied by collagen fibers around the wound; day 7 skin specimens were also subjected to mechanical testing to evaluate tensile strength. On postoperative day 3, the numbers of macrophages around the wound were significantly lower in the groups receiving 1 and 5J/cm2 irradiation, compared to the control and 10J/cm2 irradiation groups (p < 0.01). The area occupied by collagen fibers in day 7 was largest in 5J/cm2 group, followed by 1J/cm2 group, although this difference was not significant. The day 7 tensile test demonstrated significantly greater rupture strength in healing tissues from 1 and 5J/cm2 irradiation groups, compared to the control group (p < 0.05). Thus, LLLT with a 660-nm diode laser with energy density of 1 and 5J/cm2 enhanced wound healing in a rat incisional wound model. However, a higher radiation energy density yielded no significant enhancement.

生殖医学における低反応レーザー治療（LLLT）の役割

We evaluated the efficacy of supplements treatment (L-carnitine and melatonin) and low reactive level laser therapy (LLLT) and the integrated medicine program for IVF failures. After L-carnitine treatment blastocyst rate was significantly increased (37.0 % vs 60.8 %, P<0.01). After melatonin treatment good embryo rate (45.2 % vs 63.0 %, P<0.01), blastocyst rate (28.3 % vs 54.4 %, P<0.01) and good blastocyst rate (29.4 % vs 67.7 %, P<0.05) were significantly increased. After LLLT, the numbers of MII oocytes (1.7 vs 2.0, P<0.05) and the numbers of fertilized oocytes (1.6 vs 1.8, P<0.05) were significantly increased. Good embryo rate was significantly increased (64.0 % vs 79.0 %, P<0.05). In hormone supplemented frozen thawed ET cycles, pregnancy rate of day 3 embryos was significantly increased (6.7 % vs 17.8 %, P<0.05) after LLLT. And after the integrated medicine program, pregnancy rate was significantly increased (12.0 % vs 23.7 %, P<0.01).

ラット抜歯窩の創傷治癒を目的とした炭酸ガスレーザー照射による隣接歯への影響

The utility of laser irradiation has been demonstrated in basic and clinical studies, albeit with an associated risk of tissue damage. We previously tested a combination of high reactive level laser therapy (HLLT) and low reactive level laser therapy (LLLT) using a carbon dioxide laser for enhanced post-extraction wound healing and observed irreversible changes in the pulps of the teeth adjacent to the extracted tooth. The aim of this study was to elucidate the histopathological changes in the pulps of teeth adjacent to the site of carbon dioxide laser irradiation performed to achieve enhanced wound healing after tooth extraction; here we report the significance of care for the adjacent tissues in laser irradiation therapy. A total of 20 male Wistar rats (5 weeks old) were divided into an irradiation group that received HLLT combined with LLLT and a non-irradiation (control) group that did not. A tooth socket model was prepared by extracting the maxillary left first molar. HLLT and LLLT were respectively performed immediately and 1 day after tooth extraction. Laser-stimulated tissues surrounding the extracted tooth, namely, the socket and adjacent teeth, were collected from each rat both 7 and 10 days after tooth extraction. The obtained specimens were fixed in 4% paraformaldehyde, decalcified in 10% ethylenediaminetetraacetic solution, and then embedded in paraffin. Serial sagittal sections were stained with hematoxylin and eosin for histopathological examination. Laser-induced injuries, such as enamel ablation and dentin carbonization, were absent 7 days after tooth extraction in both groups. Formation of reparative dentin was observed along the rim of the laser-irradiated area in the dental pulps in the irradiation group but not the control group. Both groups showed no signs of inflammation in pulp tissues. Enamel and dentin injuries were not observed in either group at 10 days after tooth extraction, similar to the findings at 7 days after tooth extraction. Formation of reparative dentin was much more prominent at 10 days after tooth extraction than at 7 days in the irradiation group. In contrast, no formation of reparative dentin was observed at either time point in the control group. These results show that carbon dioxide laser irradiation induces the formation of reparative dentin in the pulps of teeth adjacent to the extracted tooth socket. In sum, carbon dioxide laser irradiation at the low reactive level appears to induce irreversible changes in the tissues surrounding the laser treatment site.

レーザー光による光活性化作用

Photoactivation, also known as photobiomodulation, is recognized as one effect of laser/tissue interactions. This phenomenon, which is induced by low-level laser irradiation, was reported by Mester in the late 1960s. The therapeutic method with photoactivation was defined as low-reactive level laser therapy (LLLT) by Ohshiro in 1988. Today, various clinical applications using LLLT have been reported in the field of wound healing, pain attenuation, musculoskeletal injuries and so on.This introductory review covers the fundamentals of laser/tissue interactions and the basic mechanism of photoactivation to provide a better understanding of LLLT for wound healing.

不妊症におけるLLLT の作用機序

不妊症におけるLLLT の作用機序

Low Reactive Level Laser Therapy for Mesenchymal Stromal Cells Therapies.

Low reactive level laser therapy (LLLT) is mainly focused on the activation of intracellular or extracellular chromophore and the initiation of cellular signaling by using low power lasers. Over the past forty years, it was realized that the laser therapy had the potential to improve wound healing and reduce pain and inflammation. In recent years, the term LLLT has become widely recognized in the field of regenerative medicine. In this review, we will describe the mechanisms of action of LLLT at a cellular level and introduce the application to mesenchymal stem cells and mesenchymal stromal cells (MSCs) therapies. Finally, our recent research results that LLLT enhanced the MSCs differentiation to osteoblast will also be described.

糖尿病性神経障害に対する低反応レベルレーザー照射治療 （Low reactive Level Laser Therapy: LLLT）の効果

糖尿病性神経障害に対する低反応レベルレーザー照射治療 （Low reactive Level Laser Therapy: LLLT）の効果

難治性不妊症に対する低反応レベルレーザー治療の検討

難治性不妊症に対する低反応レベルレーザー治療の検討

New Combined Laser Therapy for Small Mass of Melanocytic Nevi on the Face

A small mass of melanocytic nevi on the face is commonly treated by surgical resection. This method is associated with cosmetic complications, such as scarring and scar contracture. The use of CO2 Laser treatment to avoid these complications is increasing. However, scarring or recurrence may still occur after CO2 Laser treatment. To resolve these problems, we developed a new Combined Laser Therapy (CLT) protocol using three laser instruments.We used CO2 Laser, Nd:YAG Laser and Q-Switched Ruby Laser. The first treatment was a minimal mass reduction using CO2 Laser. The surface is covered with carbonized tissue. The second treatment with Nd:YAG Laser which removes the carbonized tissue, because the laser specifically absorbs black chromatophores. Finally, any surviving nevus cells containing melanin are destroyed with Q-Switched Ruby Laser.This method was used for 12 cases presenting with small masses of melanocytic nevi on the face. The maximum size of the mass was 20 mm. All cases resulted in a cosmetic improvement and there was no scarring or recurrence. Either satisfactory or greatly improved cosmetic results were obtained in all cases.We think that the wound healing without scarring observed in all of our cases is related to the administration of both CLT and auto-simultaneous Low reactive Level Laser Therapy (LLLT) in these cases. Therefore, this method may provide the better treatment than surgical resection in the future.

New combined laser therapy for small mass of melanocytic nevi on the face.

A small mass of melanocytic nevi on the face is commonly treated by surgical resection. This method is associated with cosmetic complications, such as scarring and scar contracture. The use of CO2 Laser treatment to avoid these complications is increasing. However, scarring or recurrence may still occur after CO2 Laser treatment. To resolve these problems, we developed a new Combined Laser Therapy (CLT) protocol using three laser instruments. We used CO2 Laser, Nd:YAG Laser and Q-Switched Ruby Laser. The first treatment was a minimal mass reduction using CO2 Laser. The surface is covered with carbonized tissue. The second treatment with Nd:YAG Laser which removes the carbonized tissue, because the laser specifically absorbs black chromatophores. Finally, any surviving nevus cells containing melanin are destroyed with Q-Switched Ruby Laser. This method was used for 12 cases presenting with small masses of melanocytic nevi on the face. The maximum size of the mass was 20 mm. All cases resulted in a cosmetic improvement and there was no scarring or recurrence. Either satisfactory or greatly improved cosmetic results were obtained in all cases. We think that the wound healing without scarring observed in all of our cases is related to the administration of both CLT and auto-simultaneous Low reactive Level Laser Therapy (LLLT) in these cases. Therefore, this method may provide the better treatment than surgical resection in the future.

LOW REACTIVE LEVEL LASER THERAPY IN THE TREATMENT OF POST HERPETIC NEURALGIA

Post herpetic neuralgia (PHN) can be an extremely painful condition which in many cases proves resistant to all the accepted forms of treatment. It is frequently most severe in the elderly and may persist for years with no predictable course. Since 1980, we have been applying low reactive level laser therapy (LLLT) for patients with PHN. We report herein on the results of a retrospective study concerning those patients in whom LLLT has been applied for pain attenuation of PHN. One hundred and twenty-three patients (73 male, 50 female, mean age: 66.11yr) have received LLLT for various entities of PHN over the past 29 years. In these cases the affected tissue area(s) was as follows: thorax and back (48 cases); head and neck (41 cases); abdomen and lumbar (17 cases); upper limb (9 cases); and lower limb (8 cases). The overall total improvement rate was 60.16%. Patient whose treatment was given within six month of onset obtained the highest improvement rate (mean, 76.34%). LLLT was effective for PHN in the acute and chronic phase, but LLLT was particularly effective for the acute phase patients whose onset before treatment was 6 months or less. The results demonstrate a significant reduction in PHN pain intensity, hypersensitivity and other complaints

THE EFFECT OF GaAlAs LASER IRRADIATION ON THE RECOVERY PROCESS OF MUSCULAR STRENGTH FOLLOWING MUSCLE FATIGUE

Low reactive-level laser therapy (LLLT) has been reported to reduce chronic and acute pain. Recently, some studies have shown that LLLT may also delay skeletal muscle fatigue during high-intensity exercise. We have hypothesized that laser irradiation may also attenuate muscle fatigue or pain experienced after sports or exercise. However, only a few reports have described the use of lasers in sports medicine. This study was conducted to determine the effectiveness of LLLT in aiding the recovery from exercise-induced skeletal muscle fatigue. Subjects and Methods: Isometric plantar flexion was repeatedly performed on 9 students until the force output declined to 50% maximal voluntary contraction (MVC). Subjects were assigned to perform 3 experiments under different LLLT conditions: laser irradiation to the neck (NKL), to the muscle (MSL), and no laser irradiation (CON). MVC and muscle hardness, girth, blood oxygen saturation, and heart rate were measured during the pre-exercise, post-exercise, and recovery phases. The neck and muscle were irradiated for 15 s using the Oh-Lase HT 2001 semi-conductor laser (830 nm; 60 mW, continuous wave), immediately after MVC measurement during the post-exercise phase.Results: The total exercise time and mean output forces were analyzed using repeated-measures and one-factor ANOVA with post-hoc tests; no significant differences were observed among the 3 conditions for the pre and post-exercise MVC levels before irradiation (NKL, 68.1% MVC; MSL, 66.4% MVC; CON, 66.1% MVC). However, the MVC at 5 and 10 min after exercise was significantly greater in the NKL and MSL groups than in the CON group (MVC after 5 min: 80.4%, 76.9%, and 69.7% for the NKL, MSL, and CON groups, respectively; MVC after 10 min: 81.8%, 81.2%, and 74.4%). Further, no significant differences were observed in the MVC recorded at 15 and 30 min. Therefore, compared to the CON group, the NKL and MSL groups exhibited early muscle-strength recovery from fatigue caused by repeated contractions.Conclusion: We concluded that LLLT at the parameters used in the present study effectively promoted the recovery of the isometric force output after muscle fatigue induced by repeated contractions, especially in the acute-exhaustion phase.

PULSED DYE LASER TREATMENT FOR RECALCITRANT VIRAL WARTS: AUTO-SIMULTANEOUS LASER TREATMENT

Verruca vulgaris is a benign proliferative lesion of the skin caused by the human papillomavirus (HPV). It is commonly seen in dermatologic and/or plastic surgery clinics. The diagnosis is straightforward, but the treatment of the lesion may be difficult and lengthy. Several treatment methods have been reported but no specific therapy of choice has been developed. It has been suggested that pulsed dye laser treatment is highly effective in the treatment of viral warts which have not responded to other treatments. Pulsed dye laser treatment is a safe method with low side effects and is mostly well-tolerated by patients. Several authors have recently reported the efficiency of pulsed dye laser treatment for warts, but no report has paid attention to the influence of low levels of laser irradiation about the periphery of the treated lesion which may induce immune activation and pain alleviation. We believe these effects are mainly due to the athermal and atraumatic simultaneous Low reactive Level Laser Therapy effect on photobiomodulated cells at the periphery of the treated lesion. We call this coincident duality of thermal damage and athermal stimulation ‘auto-simultaneous laser treatment’. We report herein on pulse dye laser treatment for a recalcitrant huge viral wart and consider the vital response.

「難治性疼痛の診断と最新の治療」各種疼痛に対するペインクリニックでの治療―神経ブロック，低反応レベルレーザー治療―

「難治性疼痛の診断と最新の治療」各種疼痛に対するペインクリニックでの治療―神経ブロック，低反応レベルレーザー治療―