Low-level laser therapy and light-emitting diode effects in the secretion of neuropeptides SP and CGRP in rat skin

Clinical Efficacy of High-Intensity Laser Therapy on Lateral Epicondylitis Patients: A Systematic Review and Meta-analysis

OBJECTIVES

Recently, high-intensity laser therapy has been used in the therapeutic protocols for pain management. We aimed to evaluate the clinical efficacy of high-intensity laser therapy versus other different modalities for improving lateral epicondylitis symptoms.

METHODOLOGY

We conducted a systematic review and meta-analysis on prospective randomized controlled trials from PubMed, Embase, Scopus, Web of Science, and Science Direct until June 2021 using relevant key words. We analyzed the data using Review Manager software (RevMan 5.4).

RESULTS

Six randomized controlled trials with 344 patients were included. There is low-quality evidence that high-intensity laser therapy generates a small reduction on pain intensity compared with a control group either during activity (mean difference = -0.98, 95% confidence interval = -1.6 to -0.35, P = 0.002) or during rest (mean difference = -0.98, 95% confidence interval = -1.68 to -0.09, P = 0.03). In addition, there is low-quality evidence that high-intensity laser therapy provides small improvements in quality of life (physical component) compared with control (mean difference = 9.76, 95% confidence interval = 2.69 to 16.83, P < 0.0001).

CONCLUSIONS

High-intensity laser therapy is an effective therapeutic modality to reduce pain and improve quality of life (36-item short form health survey physical component) in patients experiencing persistent symptoms of lateral epicondylitis. However, grip strength, hand function, and quality of life (36-item short form health survey) did not show significant differences between high-intensity laser therapy and other therapies.

A randomized comparative study between high-intensity laser vs low-intensity pulsed ultrasound both combined with exercises for the treatment of knee osteoarthritis

OBJECTIVE

To compare the effects of high-intensity laser therapy (HILT) plus exercise therapy (ET) vs low-intensity pulsed ultrasound (LIPUS) plus ET in knee osteoarthritis (KOA).

METHODS

A single blinded randomized controlled trial in an outpatient setting. There were 60 participants with grades II and III KOA based on the radiological findings in Kellgren and Lawrence grading scale. Participants were allocated randomly into three groups, study group I (HILT+ET), study group II (LIPUS+ET), and control (ET) group. Participants in the three groups received active range of motion (ROM) exercises, muscle strengthening, and flexibility exercises. Treatment was administered 5 times/wk for two successive weeks. Primary outcomes involved visual analog scale (VAS), secondary outcomes involved knee ROM, proprioceptive accuracy and Western Ontario and McMaster Universities Arthritis Index scale. All outcomes were measured pre- and post-treatment.

RESULTS

The mean age of participants was 55.4 ± 6.34, 55.2 ± 4.77 and 57 ± 6.39 years in HILT+ET, LIPUS+ET and control group respectively. There were statistically significant time-by-group effects (mixed-design multivariate analysis of variance) on all measured outcomes for all groups (P < .0001). However, HILT+ET yielded better improvement than the other groups (P < .0001). Between-group comparison revealed a significant difference in all measured outcomes between study group 1 vs study group 2, and between each study group vs the control group (P = .0001).

CONCLUSION

The effect of HILT combined with exercises achieved better results in pain, knee ROM, proprioceptive accuracy and functional disability than LIPUS combined with exercises and both are better than exercises only.

Photobiomodulation (low-level light therapy) and dry eye disease

Dry eye disease is one of the most common, chief-complaints presenting in clinical practice, with a prevalence of up to 50%. Evaporative dry eye, as a result of meibomian gland dysfunction, is thought to be the biggest component factor. Treatments for meibomian gland dysfunction aim to restore tear film homoeostasis and include warm compress therapy, eyelid hygiene, in-office meibomian gland expression and lipid-containing, artificial tears. A recent introduction to the in-office treatments available for meibomian gland dysfunction has been low-level light therapy, also known as photobiomodulation. The technique involves applying red, or near infra-red, radiation using low-power light sources and is suggested to promote tissue repair, decrease inflammation, and relieve pain. This work aims to review the available literature on the efficacy and safety of photobiomodulation in meibomian gland dysfunction and dry eye disease, as well as what is currently known about its mechanism of action.

A Prospective Comparative Study of Pulsed High-Intensity Laser Therapy and Pulsed Electromagnetic Field on Chronic Nonspecific Low Back Pain

Objective: This study explored the different effects of pulsed high-intensity laser therapy (HILT) versus pulsed electromagnetic field (EMF) in the treatment of chronic nonspecific low back pain (ChNsLBP). Methods: Between August and December 2019, 51 ChNsLBP participants with a mean age of 35.2 ± 8.6 years were enrolled in this prospective comparative study. At random, they were divided into three groups, 17 in each; HILT, EMF, and controls. HILT group was recruited for Nd:YAG laser using the following parameters: a wavelength of 1064 nm, fluency of 610-810 mJ, frequency of 10-40 Hz, average power of 10.5 W, and 120 μs short pulse duration in scanning mode. All groups received the treatment twice a week for 8 consecutive weeks. They were assessed for the modified Oswestry disability index (MODI), pain disability index (PDI), visual analog scale (VAS), and lumbar flexion range of motion (flex ROM) before and after 8 weeks of study program. Results: The results showed greater improvement in the HILT group (VAS, PDI, MODI, and lumbar flex ROM, p = 0.001) than the EMF group (VAS, p = 0.002, PDI, p = 0.045, MODI, p = 0.002, and lumbar flex ROM, p = 0.042), with significant difference between the two groups in favor of the HILT group (p ˂ 0.05). Conclusions: Depending on the results of the study, both HILT and EMF are useful physiotherapy modalities in the treatment of ChNsLBP with HILT exhibiting better outcomes than EMF. Clinical recommendations should be highlighted to instigate the use of HILT in the management of musculoskeletal disorders, distinctively ChNsLBP.

Efficacy of high intensity laser therapy in knee osteoarthritis: a double-blind controlled randomized study

OBJECTIVE

The aim of this study is to investigate the effectiveness of high intensity laser therapy on pain, functionality, flexion range of motion (FROM), and ultrasonographic cartilage measurement in patients with knee osteoarthritis.

METHODS

This study was designed as a double-blind randomized placebo-controlled study. Forty patients diagnosed with knee osteoarthritis according to the American College of Rheumatology criteria were included in the study. After obtaining written informed consent, patients were randomized into high intensity laser therapy (HILT) + exercise therapy (ET), and placebo laser (PL) + ET groups. Each patient was treated five sessions per week for 2 weeks. The outcomes measured were pain level and functional disability using the visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), respectively. The femoral cartilage thickness measurement was made ultrasonographically, and FROM was measured with goniometry.

RESULTS

Statistically significant improvements were detected in VAS, WOMAC scores, femoral cartilage thickness, and FROM at the end of the treatment (in week 2) compared to the pre-treatment period in both groups (p < 0.05). There were significant decreases in the VAS and WOMAC scores of both groups in the 6th week compared to the pre-treatment period, and the results of the FROM and femur cartilage thickness measurements were increased at statistically significant levels (p < 0.05). The VAS and WOMAC scores were significantly lower in the 6th week in HILT + ET group compared to the PL + ET group (p < 0.05). Similarly, statistically significant increases were detected in the FROM and femur cartilage thickness measurements in HILT + ET group (p < 0.05).

CONCLUSION

HILT + ET combination was more effective in KOA than the PL + ET combination. Key Points • HILT is an effective modality on pain, functional status and FROM in patients with KOA. • HILT is a modality that increases femoral cartilage thickness in patients with KOA.

Short-term clinical efficacy of the pulsed Nd: YAG laser therapy on chronic nonspecific low back pain: A randomized controlled study

BACKGROUND

Chronic non-specific low back pain (LBP) is gradually increasing among populations worldwide and affects their activities. Recently, the Nd:YAG laser has been presented in the rehabilitation field.

OBJECTIVES

This study aims to explore the short-term effects of the Nd:YAG laser on chronic non-specific LBP individuals.

METHODS

Thirty-five individuals with chronic nonspecific LBP were included in the study from December 2019 to March 2020. Randomly, they were categorized to Nd:YAG group (n = 18) and sham laser as a control (n = 17) thrice weekly for a 6-week intervention. Modified Oswestry disability index (MODI), pain disability index (PDI), visual analogue scale (VAS), and lumbar flexion range of motion (ROM) have been assessed pre and post-6 weeks of the intervention.

RESULTS

Significant improvements were observed in the Nd:YAG group (MODI, P < .001; PDI, P = .007; VAS, P < .001; lumbar ROM, P = .002), whereas the sham group showed no significant changes (MODI, P = .451; PDI, P = .339; VAS, P = .107; lumbar ROM, P = .296) after 6-week intervention. Between-group comparisons showed significant differences in tending toward the Nd:YAG group (MODI, P < .001; PDI, P = .046; VAS, P < .001; lumbar ROM, P = .003).

CONCLUSIONS

Regarding the present study outcomes, short-term pulsed Nd:YAG laser (6 weeks) may reduce functional disabilities and pain intensity, and improve the lumbar flexion ROM in patients with chronic nonspecific LBP. Further well-designed randomized controlled studies with large sample sizes should be conducted regarding laser treatment.

Under the spotlight: mechanisms of photobiomodulation concentrating on blue and green light

Photobiomodulation (PBM) describes the application of light at wavelengths ranging from 400-1100 nm to promote tissue healing, reduce inflammation and promote analgesia. Traditionally, red and near-infra red (NIR) light have been used therapeutically, however recent studies indicate that other wavelengths within the visible spectrum could prove beneficial including blue and green light. This review aims to evaluate the literature surrounding the potential therapeutic effects of PBM with particular emphasis on the effects of blue and green light. In particular focus is on the possible primary and secondary molecular mechanisms of PBM and also evaluation of the potential effective parameters for application both in vitro and in vivo. Studies have reported that PBM affects an array of molecular targets, including chromophores such as signalling molecules containing flavins and porphyrins as well as components of the electron transport chain. However, secondary mechanisms tend to converge on pathways induced by increases in reactive oxygen species (ROS) production. Systematic evaluation of the literature indicated 72% of publications reported beneficial effects of blue light and 75% reported therapeutic effects of green light. However, of the publications evaluating the effects of green light, reporting of treatment parameters was uneven with 41% failing to report irradiance (mW cm^-2) and 44% failing to report radiant exposure (J cm^-2). This review highlights the potential of PBM to exert broad effects on a range of different chromophores within the body, dependent upon the wavelength of light applied. Emphasis still remains on the need to report exposure and treatment parameters, as this will enable direct comparison between different studies and hence enable the determination of the full potential of PBM.

Involvement of Substance P in the Analgesic Effect of Low-Level Laser Therapy in a Mouse Model of Chronic Widespread Muscle Pain

Background

Low-level laser therapy (LLLT) is widely used in pain control in the field of physical medicine and rehabilitation and is effective for fibromyalgia pain. However, its analgesic mechanism remains unknown. A possible mechanism for the effect of LLLT on fibromyalgia pain is via the antinociceptive signaling of substance P in muscle nociceptors, although the neuropeptide has been known as a neurotransmitter to facilitate pain signals in the spinal cord.

Objective

To establish an animal model of LLLT in chronic muscle pain and to determine the role of substance P in LLLT analgesia.

Methods

We employed the acid-induced chronic muscle pain model, a fibromyalgia model proposed and developed by Sluka et al., and determined the optimal LLLT dosage.

Results

LLLT with 685 nm at 8 J/cm2 was effective to reduce mechanical hyperalgesia in the chronic muscle pain model. The analgesic effect was abolished by pretreatment of NK1 receptor antagonist RP-67580. Likewise, LLLT showed no analgesic effect on Tac1-/- mice, in which the gene encoding substance P was deleted. Besides, pretreatment with the TRPV1 receptor antagonist capsazepine, but not the ASIC3 antagonist APETx2, blocked the LLLT analgesic effect.

Conclusions

LLLT analgesia is mediated by the antinociceptive signaling of intramuscular substance P and is associated with TRPV1 activation in a mouse model of fibromyalgia or chronic muscle pain. The study results could provide new insight regarding the effect of LLLT in other types of chronic pain.

Effects of near infrared focused laser on the fluorescence of labelled cell membrane

Near infrared (NIR) laser light can have important reactions on live cells. For example, in a macroscopic scale, it is used therapeutically to reduce inflammation and in a single-cell scale, NIR lasers have been experimentally used to guide neuronal growth. However, little is known about how NIR lasers produce such behaviours on cells. In this paper we report effects of focussing a continuous wave 810-nm wavelength laser on in vivo 3T3 cells plasma membrane. Cell membranes were labelled with FM 4-64, a dye that fluoresces when associated to membrane lipids. Confocal microscopy was used to image cell membranes and perform fluorescence recovery after photobleaching (FRAP) experiments. We found that the NIR laser produces an increase of the fluorescence intensity at the location of laser spot. This intensity boost vanishes once the laser is turned off. The mean fluorescence increase, calculated over 75 independent measurements, equals 19%. The experiments reveal that the fluorescence rise is a growing function of the laser power. This dependence is well fitted with a square root function. The FRAP, when the NIR laser is acting on the cell, is twice as large as when the NIR laser is off, and the recovery time is 5 times longer. Based on the experimental evidence and a linear fluorescence model, it is shown that the NIR laser provokes a rise in the number of molecular associations dye-lipid. The results reported here may be a consequence of a combination of induced increments in membrane fluidity and exocytosis.

Gene Expression of Neurotrophins and Their Receptors in Keloids

The aim of this study was to assess gene expression of neurotrophins and their receptors in keloids. Skin samples of normal skin and keloids were obtained from patients in the control (n = 12) and keloid (n = 12) groups, respectively. Ribonucleic acid was extracted from the skin specimens, purified, evaluated by spectrophotometry, and used to synthesize complementary DNA. Real-time quantitative polymerase chain reaction analysis of 84 human neurotrophin genes and their receptors was performed. Twelve genes, including heat shock 27-kDa protein 1, gastrin-releasing peptide receptor, corticotropin-releasing hormone receptor 2, neuropeptide Y Y2 receptor, interleukin 6 signal transducer, nerve growth factor, metallothionein 3, B-cell chronic lymphocytic leukemia/lymphoma 2, cholecystokinin A receptor, persephin, galanin receptor 2, and fibroblast growth factor receptor 3, were down-regulated in keloid tissue compared with normal skin. The genes 27-kDa heat shock protein 1, gastrin-releasing peptide receptor, corticotropin-releasing hormone receptor 2, nerve growth factor, metallothionein 3, B-cell chronic lymphocytic leukemia/lymphoma 2, and persephin protein were considered priority genes associated with keloid formation.

Combinational light emitting diode-high frequency focused ultrasound treatment for HeLa cell

PURPOSE

Light sources such as laser and light emitting diode or ultrasound devices have been widely used for cancer therapy and regenerative medicines, since they are more cost-effective and less harmful than radiation therapy, chemotherapy or magnetic treatment. Compared to laser and low intensity ultrasound techniques, light emitting diode and high frequency focused ultrasound shows enhanced therapeutic effects, especially for small tumors.

MATERIALS AND METHODS

We propose combinational light emitting diode-high frequency focused ultrasound treatment for human cervical cancer HeLa cells. Individual red, green, and blue light emitting diode light only, high frequency focused ultrasound only, or light emitting diode light combined with high frequency focused ultrasound treatments were applied in order to characterize the responses of HeLa cells.

RESULTS

Cell density exposed by blue light emitting diode light combined with high frequency focused ultrasound (2.19 ± 0.58%) was much lower than that of cells exposed by red and green light emitting diode lights (81.71 ± 9.92% and 61.81 ± 4.09%), blue light emitting diode light (11.19 ± 2.51%) or high frequency focused ultrasound only (9.72 ± 1.04%).

CONCLUSIONS

We believe that the proposed combinational blue light emitting diode-high frequency focused ultrasound treatment could have therapeutic benefits to alleviate cancer cell proliferation.

Effects of High-Voltage Electrical Stimulation in Improving the Viability of Musculocutaneous Flaps in Rats

BACKGROUND

The musculocutaneous flap of the transverse rectus abdominis muscle is a technique used for breast reconstruction, and one of the complications of this procedure is tissue necrosis. The objective of the study is to determine the effect of high-voltage electrical stimulation (HVES) in the transverse rectus abdominis muscle flap in rats.

METHODS

Fourteen rats underwent surgery for obtaining the flap. The rats were distributed into 2 homogeneous groups: group 1 underwent both surgery and the use of HVES, whereas group 2 underwent just the surgery (control). Electrical stimulation was applied immediately after surgery and for 2 consecutive days. The percentage of necrotic area was analyzed using the Image J software, and blood flow was assessed by infrared thermography in different regions of the flap, divided into 4 zones according to the proximity of the pedicle of the inferior epigastric artery.

RESULTS

The results were analyzed using a Student t test, where group 1 experienced a necrotic area of 26.2%, and group 2 had an area of 54.5%. Regarding the temperature, the 2 groups showed increase in the minimum and maximum temperature on the fourth postoperative day.

CONCLUSION

The HVES appeared to have a positive influence on the viability of the flap.

Efficacy of photobiomodulation therapy on masseter thickness and oral health-related quality of life in children with spastic cerebral palsy

The study aimed to evaluate the efficacy of photobiomodulation therapy (PBMT) on bilateral masseter muscle thickness and amplitude of mouth opening in children with spastic cerebral palsy (CP), and the impact on their oral health-related quality of life (OHRQOL). Three groups were included: experimental CP group (EG: n = 26 with oral complaints), positive control CP group (PCG: n = 26 without complaints), and negative control group (NCG: n = 26 without CP). In the EG, the masseter muscles on both sides were irradiated with an infrared low-level Ga-Al-As laser (λ = 808 ± 3 nm, 120 mW) using a 3 J/cm² energy dose per site, with a 20 s exposure time per site (spot area: 4 mm²; irradiance: 3 W/cm²; energy delivery per point: 2.4 J) six times over six consecutive weeks. Masseter thickness, assessed through ultrasonography, and the amplitude of mouth opening were measured in the EG before and after six applications of PBMT and once in the PCG and NCG. The Parental-Caregiver Perception Questionnaire (P-CPQ) was used to evaluate OHRQOL. ANOVA, chi-square, t tests, and multilevel linear regression were used for statistical analysis. In the EG, the study results revealed average increments of 0.77 (0.08) millimeter in masseter thickness (P < 0.05) and 7.39 (0.58) millimeter for mouth opening (P < 0.05) and reduction in all P-CPQ domains (P < 0.001), except for social well-being. The six applications of PBMT increased masseter thickness and mouth opening amplitude and reduced the impact of spastic CP on OHRQOL.

A Double-Blind, Placebo-Controlled Randomized Evaluation of the Effect of Low-Level Laser Therapy on Venous Leg Ulcers

This study aimed to determine the effect of low-level laser therapy (LLLT) on chronic venous leg ulcers (VLUs). A double-blinded prospective randomized controlled trial was conducted to compare incidence of complete wound closure, ulcer size and pain reduction in patients randomized to 24 treatments of placebo or LLLT (635 nm) over 12 weeks. Patients presented with a 6-week history of VLUs ranging in size from 5 to 20 cm2. Venous origin was confirmed by Doppler ultrasound and an ankle brachial index of 0.8 or greater. Of 24 patients, 23% of the test group (n = 13) and 18% of placebo group (n = 11) achieved complete wound closure. At 12 weeks, patients in test and placebo groups had a mean surface area reduction of 6.26 cm2 ( P < .0001) and 6.72 cm2 ( P < .005), respectively, and a mean pain score decrease of 43.54 points ( P < .0001) and 25.73 points ( P = .002) respectively. Differences between groups was not statistically significant for wound closure ( P = 1.0) or ulcer size ( P = .80). Mean ulcer pain was significantly reduced from initiation of treatment compared with 4 weeks’ follow-up after 12 weeks with LLLT ( P < .01). Within the limitations of the study, LLLT may not have early effects as an adjunctive therapy to wound healing of VLUs, but LLLT may have delayed effects on VLU healing and associated pain, which requires further study.

Efficacy of pulsed Nd:YAG laser in the treatment of patients with knee osteoarthritis: a randomized controlled trial

The purpose of this study was to investigate the effects of pulsed Nd:YAG laser plus glucosamine/chondroitin sulfate (GCS) in patients with knee osteoarthritis (KOA) by examining changes in pain and knee function, as well as synovial thickness (ST) and femoral cartilage thickness (FCT). Sixty-seven male patients participated, with a mean (SD) age of 53.85 (4.39) years, weight of 84.01 (4.70) kg, height of 171.51 (3.96) cm, and BMI of 28.56 (1.22). Group 1 was treated with high-intensity laser therapy (HILT), GCS, and exercises (HILT + GCS + EX). Group 2 was treated with GCS plus exercises (GCS + EX), and group 3 received placebo laser plus exercises (PL + EX). The outcomes measured were pain level and functional disability using the visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), respectively. ST and FCT were measured by ultrasound examination. Statistical analyses were performed to compare differences between baseline and after 6 weeks of treatment and then after 3 months of follow-up. Statistical significance was set at p < 0.05. VAS and WOMAC were significantly decreased in all groups after 6 weeks, with nonsignificant differences between 6 weeks and 3 months of follow-up. ST was significantly decreased in the HILT + GCS + EX group posttreatment, with nonsignificant decreases in the GCS + EX and PL + EX groups, as well as nonsignificant differences to FCT in all groups. Overall, pulsed Nd:YAG laser combined with GCS and exercises was more effective than GCS + EX and exercises alone in the treatment of KOA patients.

Observation of an improved healing process in superficial skin wounds after irradiation with a blue-LED haemostatic device

The healing process of superficial skin wounds treated with a blue-LED haemostatic device is studied. Four mechanical abrasions are produced on the back of 10 Sprague Dawley rats: two are treated with the blue-LED device, while the other two are left to naturally recover. Visual observations, non-linear microscopic imaging, as well as histology and immunofluorescence analyses are performed 8 days after the treatment, demonstrating no adverse reactions neither thermal damages in both abraded areas and surrounding tissue. A faster healing process and a better-recovered skin morphology are observed: the treated wounds show a reduced inflammatory response and a higher collagen content. Blue LED induced photothermal effect on superficial abrasions.

The dark art of light measurement: accurate radiometry for low-level light therapy

Lasers and light-emitting diodes are used for a range of biomedical applications with many studies reporting their beneficial effects. However, three main concerns exist regarding much of the low-level light therapy (LLLT) or photobiomodulation literature; (1) incomplete, inaccurate and unverified irradiation parameters, (2) miscalculation of ‘dose,’ and (3) the misuse of appropriate light property terminology. The aim of this systematic review was to assess where, and to what extent, these inadequacies exist and to provide an overview of ‘best practice’ in light measurement methods and importance of correct light measurement. A review of recent relevant literature was performed in PubMed using the terms LLLT and photobiomodulation (March 2014–March 2015) to investigate the contemporary information available in LLLT and photobiomodulation literature in terms of reporting light properties and irradiation parameters. A total of 74 articles formed the basis of this systematic review. Although most articles reported beneficial effects following LLLT, the majority contained no information in terms of how light was measured (73 %) and relied on manufacturer-stated values. For all papers reviewed, missing information for specific light parameters included wavelength (3 %), light source type (8 %), power (41 %), pulse frequency (52 %), beam area (40 %), irradiance (43 %), exposure time (16 %), radiant energy (74 %) and fluence (16 %). Frequent use of incorrect terminology was also observed within the reviewed literature. A poor understanding of photophysics is evident as a significant number of papers neglected to report or misreported important radiometric data. These errors affect repeatability and reliability of studies shared between scientists, manufacturers and clinicians and could degrade efficacy of patient treatments. Researchers need a physicist or appropriately skilled engineer on the team, and manuscript reviewers should reject papers that do not report beam measurement methods and all ten key parameters: wavelength, power, irradiation time, beam area (at the skin or culture surface; this is not necessarily the same size as the aperture), radiant energy, radiant exposure, pulse parameters, number of treatments, interval between treatments and anatomical location. Inclusion of these parameters will improve the information available to compare and contrast study outcomes and improve repeatability, reliability of studies.

Does dexamethasone act in neuropeptides SP and CGRP in neurogenic inflammation of the skin? An experimental study

PURPOSE

To investigate the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) after subcutaneous injection of dexamethasone prior to skin incision in rats.

METHODS

Twenty seven Wistar-EPM-1 rats were randomly divided into three groups. The sham group (SG) of rats was injected with 0.9 % saline. The second group (Dexa) was injected with 1.0 mg/kg dexamethasone, and the third group (Dexa+) was injected with 10.0 mg/kg dexamethasone. In all groups, the three subcutaneous injections were performed 30 minutes prior to the surgical skin incision and tissue collection. SP and CGRP (15 kDa pro-CGRP and 5 kDa CGRP) were quantified by Western Blotting.

RESULTS

No statistically significant differences (p>0.05) were found in pro-CGRP, CGRP and SP values in all three groups.

CONCLUSION

The anti-inflammatory effect of dexamethasone did not occur when the substance P and calcitonin gene-related peptide levels were altered during the neurogenic inflammation process of skin wound healing in rats.

Low level light therapy by LED of different wavelength induces angiogenesis and improves ischemic wound healing

BACKGROUND AND OBJECTIVE

Low-level light therapy (LLLT) has been revealed as a potential means to improve wound healing. So far, most studies are being performed with irradiation in the red to near-infrared spectra. Recently, we showed that blue light (470 nm) can significantly influence biological systems such as nitric oxide (NO) metabolism and is able to release NO from nitrosyl-hemoglobin or mitochondrial protein complexes. Therefore, the aim of this study was to evaluate and compare the therapeutic value of blue or red light emitting diodes (LEDs) on wound healing in an ischemia disturbed rodent flap model.

STUDY DESIGN/MATERIALS AND METHODS

An abdominal flap was rendered ischemic by ligation of one epigastric bundle and subjected to LED illumination with a wavelength of 470 nm (blue, n = 8) or 629 nm (red, n = 8) each at 50 mW/cm(2) and compared to a non-treated control group (n = 8). Illumination was performed for 10 minutes on five consecutive days.

RESULTS

LED therapy with both wavelengths significantly increased angiogenesis in the sub-epidermal layer and intramuscularly (panniculus carnosus muscle) which was associated with significantly improved tissue perfusion 7 days after the ischemic insult. Accordingly, tissue necrosis was significantly reduced and shrinkage significantly less pronounced in the LED-treated groups of both wavelengths.

CONCLUSIONS

LED treatment of ischemia challenged tissue improved early wound healing by enhancing angiogenesis irrespective of the wavelength thus delineating this noninvasive means as a potential, cost effective tool in complicated wounds.