Effects of diclofenac sodium and He:Ne laser irradiation on plasmatic fibrinogen levels in inflammatory processes

Effect of photobiomodulation on neuropathic pain of diabetic origin: a narrative review of the literature

To update the literature on the effectiveness of photobiomodulation (PBM) therapy in relieving pain in patients with diabetic peripheral neuropathy (DPN) compared to the effects of post-intervention, control/placebo groups, and other therapies. Search on the following databases: PORTAL PERIODICOS CAPES, PUBMED, GOOGLE ACADEMIC/SCHOLAR, SCOPUS, SCIELO, CENTRAL, and MEDLINE. Manual search: 1) manually capture the references of relevant articles originally selected to be included in the eligible studies. Two independent researchers performed the screening and selection of studies, methods assessment, and data extraction with unblinded authors and impressions. Subsequently, the full text of the originally selected studies was screened. The screening form registered the criteria for excluding literature from the full-text screening. The screening resulted in a total of 1692 citations. Out of these, 1402 citations were examined for titles and abstracts, followed by the removal of duplicated studies; therefore, 68 articles remained for full-text evaluation. 54 articles were excluded after full-text screening. Fourteen articles met the selection criteria, hence being selected and included in this narrative review. PBM showed to be a promising modality in relieving painful symptoms in DPN, especially when implemented in combination with other therapies, by improving the quality of life of diabetic patients.

Osteogenic Potential of Bovine Bone Graft in Combination with Laser Photobiomodulation: An Ex Vivo Demonstrative Study in Wistar Rats by Cross-Linked Studies Based on Synchrotron Microtomography and Histology

BACKGROUND

Alveolar bone defects are usually the main concern when planning implant treatments for the appropriate oral rehabilitation of patients. To improve local conditions and achieve implant treatments, there are several methods used for increasing bone volume, among which one of the most successful, versatile, and effective is considered to be guided bone regeneration. The aim of this demonstrative study was to propose an innovative analysis protocol for the evaluation of the effect of photobiomodulation on the bone regeneration process, using rat calvarial defects of 5 mm in diameter, filled with xenograft, covered with collagen membrane, and then exposed to laser radiation.

METHODS

The animals were sacrificed at different points in time (i.e., after 14, 21, and 30 days). Samples of identical dimensions were harvested in order to compare the results obtained after different periods of healing. The analysis was performed by cross-linking the information obtained using histology and high-resolution synchrotron-based tomography on the same samples. A comparison was made with both the negative control (NC) group (with a bone defect which was left for spontaneous healing), and the positive control (PC) group (in which the bone defects were filled with xenografts and collagen membrane without receiving laser treatment).

RESULTS

We demonstrated that using photobiomodulation provides a better healing effect than when receiving only the support of the biomaterial. This effect has been evident for short times treatments, i.e., during the first 14 days after surgery.

CONCLUSION

The proposed analysis protocol was effective in detecting the presence of higher quantities of bone volumes under remodeling after photobiomodulation with respect to the exclusive bone regeneration guided by the xenograft.

JA, Zamuner SR. Analgesic Effect of Photobiomodulation on Bothrops Moojeni Venom-Induced Hyperalgesia: A Mechanism Dependent on Neuronal Inhibition, Cytokines and Kinin Receptors Modulation

Background

Envenoming induced by Bothrops snakebites is characterized by drastic local tissue damage that involves an intense inflammatory reaction and local hyperalgesia which are not neutralized by conventional antivenom treatment. Herein, the effectiveness of photobiomodulation to reduce inflammatory hyperalgesia induced by Bothrops moojeni venom (Bmv), as well as the mechanisms involved was investigated.

Methodology/Principal Findings

Bmv (1 μg) was injected through the intraplantar route in the right hind paw of mice. Mechanical hyperalgesia and allodynia were evaluated by von Frey filaments at different time points after venom injection. Low level laser therapy (LLLT) was applied at the site of Bmv injection at wavelength of red 685 nm with energy density of 2.2 J/cm² at 30 min and 3 h after venom inoculation. Neuronal activation in the dorsal horn spinal cord was determined by immunohistochemistry of Fos protein and the mRNA expression of IL-6, TNF-α, IL-10, B1 and B2 kinin receptors were evaluated by Real time-PCR 6 h after venom injection. Photobiomodulation reversed Bmv-induced mechanical hyperalgesia and allodynia and decreased Fos expression, induced by Bmv as well as the mRNA levels of IL-6, TNF-α and B1 and B2 kinin receptors. Finally, an increase on IL-10, was observed following LLLT.

Conclusion/Significance

These data demonstrate that LLLT interferes with mechanisms involved in nociception and hyperalgesia and modulates Bmv-induced nociceptive signal. The use of photobiomodulation in reducing local pain induced by Bothropic venoms should be considered as a novel therapeutic tool for the treatment of local symptoms induced after bothropic snakebites.

Envenoming caused by Bothrops snakes is characterized by drastic local tissue damage involving hemorrhage, blistering, myonecrosis, prominent inflammatory response and intense pain. The most effective treatment for Bothrops snakebites is antivenom therapy, which is very efficient in reversing systemic effects of envenomation but not the severe local effects. Thus, there exists a need to find novel complementary therapies that may further assist in the prevention or even counteract the severe local effects of bothrops snakebite. Several studies have shown the effectiveness of photobiomodulation in reducing local effects induced by Bothropic venoms, however its mechanisms still remain unknown. In this study, we analyzed the effectiveness of photobiomodulation in reducing BmV-induced mechanical allodynia and hyperalgesia as well as part of the mechanisms involved in such effect. Results demonstrate that photobiomodulation reduces venom-induced mechanical allodynia and hyperalgesia and this effect depends on a decrease of nociceptor activation at the spinal cord level and by a modulation of pro- and anti- inflammatory cytokines as well as kinin receptors at mRNA transcriptional levels. These findings make phtobiomodulation a promising candidate to be associated to antivenom therapy for the treatment of the local response induced by Bothrops venoms.

Evaluation of the improvement effect of laser acupuncture biostimulation in asthmatic children by exhaled inflammatory biomarker level of nitric oxide

Variable therapy of asthma is not sufficient yet to achieve good asthma control. Therapy decision requires serial investigations. Low-level laser acupuncture is a suitable non-invasive modality of complementary medicine. The exhaled breath condensate (EBC) is easy and useful to evaluate the efficacy of drugs or novel therapy. This study aimed to evaluate the effectiveness of low-level laser biostimulation of acupuncture points on asthma improvement in children. Forty-eight asthmatic children were subdivided into case (laser) group, which received 12 direct contact low-power laser acupuncture sessions (three sessions/week) on specific traditional Chinese acupuncture points for bronchial asthma, and control asthmatic group, which received sham laser acupuncture on the same acupoints and number of sessions of the case (laser) group. Low-power Multichannel Aculas-AM laser (grade II) of wave length 780 nm, output power 800 mw, and beam spot size 0.1 cm² with continuous mode was used. Eighteen acupoints were stimulated for 2 min, giving energy of 9.6 J/cm²/acupoint. The total session time was 3 min. Both groups were evaluated pre- and post-laser acupuncture intervention by recording levels of asthma control, pulmonary function, and EBC nitric oxide. In the case (laser) group, 91.7 % of patients experienced an improvement in the level of asthma control versus 25 % in the control group (p < 0.001). This was associated with a significant decrease of the breath condensate FENO concentration (p < 0.001) and significant increase of spirometry parameters (p < 0.001) in the case (laser) group. Application of laser acupuncture treatment given with conventional therapy can effectively improve bronchial asthma more than prescription of medications alone could.

Low-level laser therapy prevents prodromal signal complications on saphenectomy post myocardial revascularization

BACKGROUND AND OBJECTIVE

One of the most frequent treatments for ischemic heart disease is myocardial revascularization, often applying the saphenous vein as a coronary graft. However, postoperative complications may occur, such as saphenous dehiscence. According to the literature, low-level laser therapy (LLLT) has been used in the treatment of several inflammatory processes in patients. Recently, its uses have expanded to include LLLT preventive therapy and postoperative treatment. Despite our department's successful application of LLLT in the treatment of saphenectomy incisions, many colleagues are still uncertain as to laser therapy's benefits. Therefore, the study's purpose was to evaluate tissue repair of prodromal surgical incisions after the administration of LLLT.

MATERIALS AND METHODS

The pilot study included 14 patients, divided into two groups. Both groups of patients received the traditional treatment; additionally, the Laser Group (n = 7) received diode laser treatment (λ = 780 nm, fluence = 19 J/cm(2), pulse = 25 mW, time = 30 sec, energy = 0.75 J, irradiance = 625 mW/cm(2), beam spot size 0.04 cm(2)), which was applied on the edges of the saphenectomy incision. The Control Group (n = 7) received conventional treatment exclusively.

RESULTS

In the Laser Group: all seven patients showed significant improvement, whereas the Control Group had twice as many complications, including critical rates of incisional dehiscence.

CONCLUSIONS

LLLT was valuable in preventing prodromal complications in saphenectomy post myocardial revascularization.

Effects of a low-level semiconductor gallium arsenide laser on local pathological alterations induced by Bothrops moojeni snake venom

Antivenom therapy has been ineffective in neutralizing the tissue damage caused by snakebites. Among therapeutic strategies to minimize effects after envenoming, it was hypothesized that a low level laser would reduce complications and reduce the severity of local snake venom effects. In the current study, the effect of a low-level semiconductor gallium arsenide (GaAs) laser on the local pathological alterations induced by B. moojeni snake venom was investigated. The experimental groups consisted of five male mice, each administered either B. moojeni venom (VB), B. moojeni venom + antivenom (VAV), B. moojeni venom + laser (VL), B. moojeni venom + antivenom + laser (VAVL), or sterile saline solution (SSS) alone. Paw oedema was induced by intradermal administration of 0.05 mg kg(-1) of B. moojeni venom and was expressed in mm of directly induced oedema. Mice received by subcutaneous route 0.20 mg kg(-1) of venom for evaluating nociceptive activity and the time (in seconds) spent in licking and biting the injected paw was taken as an indicator of pain response. Inflammatory infiltration was determined by counting the number of leukocytes present in the gastrocnemius muscle after venom injection (0.10 mg kg(-1)). For histological examination of myonecrosis, venom (0.10 mg kg(-1)) was administered intramuscularly. The site of venom injection was irradiated by the GaAs laser and some animals received antivenom intraperitoneally. The results indicated that GaAs laser irradiation can help in reducing some local effects produced by the B. moojeni venom in mice, stimulating phagocytosis, proliferation of myoblasts and the regeneration of muscle fibers.

Evaluation of the effectiveness of diode laser on pain and edema in individuals with cleft lip and palate submitted to secondary bone graft

OBJECTIVE : To clinically evaluate the effects of diode laser, Gallium-Aluminum-Arsenide laser (GaAlAs), on the pain and edema after secondary alveolar bone graft. DESIGN : Case-control, double-blind study. Setting : Institutional tertiary referral hospital. Participants : The sample was composed of 60 individuals with complete unilateral cleft lip and palate, of both genders, aged 9 to 15 years, submitted to secondary alveolar bone graft. MAIN OUTCOME MEASURES : The individuals were divided into an experimental group (patients irradiated with diode laser GaAlAs, energy density of 4 J/cm(2), power of 100 mW, and wavelength in the infrared spectrum, for 10 seconds per point on 10 points, adding up to a dose of 40 J/cm(2)) and a placebo group (simulated laser application for 60 seconds per point, also on 10 points). Applications were made on the receptor site immediately postoperatively and after 24 and 48 hours. The pain and edema were assessed preoperatively and at each application. RESULTS : The two groups presented increase in pain and edema in 24 and 48 hours. No statistically significant difference was found between groups. CONCLUSIONS : According to the present methodology, the use of low-level laser to control the pain and edema in the postoperative period of secondary alveolar bone graft was not effective.

Efficacy of low-level laser therapy for body contouring and spot fat reduction

BACKGROUND

Low-level laser therapy (LLLT) is commonly used in medical applications, but scientific studies of its efficacy and the mechanism by which it causes loss of fat from fat cells for body contouring are lacking. This study examined the effectiveness and mechanism by which 635–680 nm LLLT acts as a non-invasive body contouring intervention method.

METHODS

Forty healthy men and women ages 18–65 years with a BMI <30 kg/m2 were randomized 1:1 to laser or control treatment. Subject's waistlines were treated 30 min twice a week for 4 weeks. Standardized waist circumference measurements and photographs were taken before and after treatments 1, 3, and 8. Subjects were asked not to change their diet or exercise habits. In vitro assays were conducted to determine cell lysis, glycerol, and triglyceride release.

RESULTS

Data were analyzed for those with body weight fluctuations within 1.5 kg during 4 weeks of the study. Each treatment gave a 0.4–0.5 cm loss in waist girth.Cumulative girth loss after 4 weeks was −2.15 cm (−0.78 ± 2.82 vs. 1.35 ± 2.64 cm for the control group,p < 0.05). A blinded evaluation of standardized pictures showed statistically significant cosmetic improvement after 4 weeks of laser treatment. In vitro studies suggested that laser treatment increases fat loss from adipocytes by release of triglycerides, without inducing lipolysis or cell lysis.

CONCLUSIONS

LLLT achieved safe and significant girth loss sustained over repeated treatments and cumulative over 4 weeks of eight treatments. The girth loss from the waist gave clinically and statistically significant cosmetic improvement.

High-power diode laser use on Fordyce granule excision: a case report

BACKGROUND

Fordyce granules are conventionally considered to be a developmental oral lesion with a higher incidence in men.

OBJECTIVE

To report a clinical case of surgical lip Fordyce granule excision in a 19-year-old male.

METHODS

Fordyce granules were excised using a high-power diode laser (gallium arsenide [GaAs], Diode Vision®, MDL, 10 Dental Laser Unit, GmbH, Lower Saxony, Germany) with wavelength emission at 980 ± 10 nm, in a continuous wave mode, pulse width of 0.5 μs, fiber optic delivery system of 400 μm in diameter, at 2.5 W. Subsequently, low-intensity laser therapy was applied (gallium-aluminum-arsenide [GaAlAs], at 670 nm, 50 mW, at 4 J/cm(2); Dentoflex®, São Paulo, Brazil] in order to stimulate a faster wound tissue-healing process and less postoperative pain and inflammation.

CONCLUSION

The excellent esthetic result demonstrated the effectiveness of both high- and low-intensity laser therapy on the excision of Fordyce granules.

Low-level laser therapy (LLLT; 780 nm) acts differently on mRNA expression of anti- and pro-inflammatory mediators in an experimental model of collagenase-induced tendinitis in rat

Low-level laser therapy (LLLT) has been found to produce anti-inflammatory effects in a variety of disorders. Tendinopathies are directly related to unbalance in expression of pro- and anti-inflammatory cytokines which are responsible by degeneration process of tendinocytes. In the current study, we decided to investigate if LLLT could reduce mRNA expression for TNF-α, IL-1β, IL-6, TGF-β cytokines, and COX-2 enzyme. Forty-two male Wistar rats were divided randomly in seven groups, and tendinitis was induced with a collagenase intratendinea injection. The mRNA expression was evaluated by real-time PCR in 7th and 14th days after tendinitis. LLLT irradiation with wavelength of 780 nm required for 75 s with a dose of 7.7 J/cm(2) was administered in distinct moments: 12 h and 7 days post tendinitis. At the 12 h after tendinitis, the animals were irradiated once in intercalate days until the 7th or 14th day in and them the animals were killed, respectively. In other series, 7 days after tendinitis, the animals were irradiated once in intercalated days until the 14th day and then the animals were killed. LLLT in both acute and chronic phases decreased IL-6, COX-2, and TGF-β expression after tendinitis, respectively, when compared to tendinitis groups: IL-6, COX-2, and TGF-β. The LLLT not altered IL-1β expression in any time, but reduced the TNF-α expression; however, only at chronic phase. We conclude that LLLT administered with this protocol reduces one of features of tendinopathies that is mRNA expression for pro-inflammatory mediators.

Anti-inflammatory effect of low-level laser and light-emitting diode in zymosan-induced arthritis

OBJECTIVE

The aim of this work was to investigate the effect of low-level laser therapy (LLLT) and light-emitting diode (LED) on formation of edema, increase in vascular permeability, and articular joint hyperalgesia in zymosan-induced arthritis.

BACKGROUND DATA

It has been suggested that low-level laser and LED irradiation can modulate inflammatory processes.

MATERIAL AND METHODS

Arthritis was induced in male Wistar rats (250-280 g) by intra-articular injection of zymosan (1 mg in 50 microL of a sterile saline solution) into one rear knee joint. Animals were irradiated immediately, 1 h, and 2 h after zymosan administration with a semiconductor laser (685 nm and 830 nm) and an LED at 628 nm, with the same dose (2.5 J/cm(2)) for laser and LED. In the positive control group, animals were injected with the anti-inflammatory drug dexamethasone 1 h prior to the zymosan administration. Edema was measured by the wet/dry weight difference of the articular tissue, the increase in vascular permeability was assessed by the extravasation of Evans blue dye, and joint hyperalgesia was measured using the rat knee-joint articular incapacitation test.

RESULTS

Irradiation with 685 nm and 830 nm laser wavelengths significantly inhibited edema formation, vascular permeability, and hyperalgesia. Laser irradiation, averaged over the two wavelengths, reduced the vascular permeability by 24%, edema formation by 23%, and articular incapacitation by 59%. Treatment with LED (628 nm), with the same fluence as the laser, had no effect in zymosan-induced arthritis.

CONCLUSION

LLLT reduces inflammatory signs more effectively than LED irradiation with similar irradiation times (100 sec), average outputs (20 mW), and energy doses (2 J) in an animal model of zymosan-induced arthritis. The anti-inflammatory effects of LLLT appear to be a class effect, which is not wavelength specific in the red and infrared parts of the optical spectrum.

Electrophysiologic effects of a therapeutic laser on myofascial trigger spots of rabbit skeletal muscles

OBJECTIVE

To better understand the mechanisms of therapeutic lasers for treating human myofascial trigger points, we designed a blinded controlled study of the effects of a therapeutic laser on the prevalence of endplate noise (EPN) recorded from the myofascial trigger spot (MTrS) of rabbit skeletal muscle.

DESIGN

In eight rabbits, one MTrS in each biceps femoris muscle was irradiated with a 660-nm, continuous-wave, gallium-aluminum-arsenate (GaAlAs) laser, at 9 J/cm2. The contralateral side of muscle was treated with a sham laser. Each rabbit received six treatments. The immediate and cumulative effects were assessed by the prevalence of EPN with electromyographic (EMG) recordings after the first and last treatments.

RESULTS

Compared with pretreatment values, the percentages of EPN prevalence in the experimental side after the first and last treatments were significantly reduced (P < 0.01 for both). The change in EPN prevalence in the experimental side was significantly greater than in the control side immediately after the first and last treatments (P < 0.05). However, no significant differences were noted between the first and last treatments (P > 0.05).

CONCLUSIONS

In our study, immediate and cumulative effects of a GaAlAs laser applied on MTrS were demonstrated on the basis of the assessment of EPN prevalence. It seems that laser irradiation may inhibit the irritability of an MTrS in rabbit skeletal muscle. This effect may be a possible mechanism for myofascial pain relief with laser therapy.

Influence of He-Ne laser therapy on the dynamics of wound healing in mice treated with anti-inflammatory drugs

We determined the effects of helium-neon (He-Ne) laser irradiation on wound healing dynamics in mice treated with steroidal and non-steroidal anti-inflammatory agents. Male albino mice, 28-32 g, were randomized into 6 groups of 6 animals each: control (C), He-Ne laser (L), dexamethasone (D), D + L, celecoxib (X), and X + L. D and X were injected im at doses of 5 and 22 mg/kg, respectively, 24 h before the experiment. A 1-cm long surgical wound was made with a scalpel on the abdomens of the mice. Animals from groups L, D + L and X + L were exposed to 4 J (cm(2))-1 day-1 of He-Ne laser for 12 s and were sacrificed on days 1, 2, or 3 after the procedure, when skin samples were taken for histological examination. A significant increase of collagen synthesis was observed in group L compared with C (168 +/- 20 vs 63 +/- 8 mm(2)). The basal cellularity values on day 1 were: C = 763 +/- 47, L = 1116 +/- 85, D = 376 +/- 24, D + L = 698 +/- 31, X = 453 +/- 29, X + L = 639 +/- 32 U/mm(2). These data show that application of L increases while D and X decrease the inflammatory cellularity compared with C. They also show that L restores the diminished cellularity induced by the anti-inflammatory drugs. We suggest that He-Ne laser promotes collagen formation and restores the baseline cellularity after pharmacological inhibition, indicating new perspectives for laser therapy aiming to increase the healing process when anti-inflammatory drugs are used.

Effects of Laser Therapy in CO2Laser Wounds in Rats

OBJECTIVE

The aim of this study was to assess the effects of laser therapy and its possible dose dependency on the healing of CO2 laser surgical wounds.

BACKGROUND DATA

Several reports from our group and others have indicated that light therapies may improve healing, depending on wavelength, dose, intensity of the light, and both local and systemic conditions.

METHODS

Circular surgical wounds were created on the dorsum of Wistar rats, which were separated into three groups (A, B, and C). Group A acted as control and had no additional treatment. Groups B and C were irradiated with GaAlAs lambda685-nm laser light, either with 20 J/cm2 (Group B) or 40 J/cm2 (Group C). The animals were humanely killed at the end of the experimental period; specimens were taken and routinely processed to wax and stained with Hematoxylin and Eosin, Sirius Red, and alpha-Smooth Muscle Actin (alphaSMA).

RESULTS

Laser-irradiated groups showed a healing process characterized by a more prominent fibroblastic proliferation, with young fibroblasts actively producing collagen; no myofibroblasts were found. No statistically significant differences were observed when the different doses were compared.

CONCLUSION

It may be concluded that, using this methodology, laser therapy has a positive effect in wound healing produced by CO2 laser, and the dose has no influence on the treatment.

Photobiomodulation of Pain and Inflammation in Microcrystalline Arthropathies: Experimental and Clinical Results

OBJECTIVE

This article presents the results of laser therapy in crystal (hydroxyapatite, calcium pyrophosphate, and urates) deposition-induced arthritis in rats and the clinical applications in humans.

BACKGROUND DATA

Microcrystalline arthropathies are prevalent among geriatric patients, who are more vulnerable to the side effects of drugs. The effectiveness of laser therapy for pain relief, free of side effects, has been reported in painful conditions.

METHODS

Two milligrams of each of the above-mentioned crystals was injected in both joints of the back limbs in three groups of rats; these groups were then treated with laser irradiation. Three other groups received no treatment after the injections. We determined the plasmatic levels of inflammatory markers (fibrinogen, prostaglandin E2, and TNF(alpha)), tissues (prostaglandin E(2)) and conducted anatomopathological studies. Twenty-five patients with acute gout arthritis were randomized into two groups and treated over 5 days: group A, diclofenac 75 mg orally, twice a day; and group B, laser irradiation once a day. Forty-nine patients with knee chronic pyrophosphate arthropathy were randomized into two groups and treated over 21 days; group A, diclofenac 50 mg orally, twice a day; and group B, laser irradiation once a day. Thirty patients with shoulder chronic hydroxyapatite arthropathy were randomized into two groups and treated over 21 days; group A, diclofenac 50 mg orally, twice a day; and group B, laser irradiation once a day.

RESULTS

Fibrinogen, prostaglandin E(2), and TNF(alpha) concentrations in the rats injected with crystals and treated with laser decreased significantly as compared with the groups injected with crystals without treatment. Both laser therapy and diclofenac achieved rapid pain relief in patients with acute gouty arthritis without significant differences in efficacy. Laser therapy was more effective than diclofenac in patients with chronic pyrophosphate arthropathy and in patients with chronic apatite deposition disease.

CONCLUSION

Laser therapy represents an effective treatment in the therapeutic arsenal of microcrystalline arthropathies.

Effect of LLLT Ga-Al-As (685 nm) on LPS-induced inflammation of the airway and lung in the rat

The purpose of this study was to investigate the effect of low level laser therapy (LLLT) on male Wistar rat trachea hyperreactivity (RTHR), bronchoalveolar lavage (BAL) and lung neutrophils influx after Gram-negative bacterial lipopolyssacharide (LPS) intravenous injection. The RTHR, BAL and lung neutrophils influx were measured over different intervals of time (90 min, 6 h, 24 h and 48 h). The energy density (ED) that produced an anti-inflammatory effect was 2.5 J/cm(2), reducing the maximal contractile response and the sensibility of trachea rings to methacholine after LPS. The same ED produced an anti-inflammatory effect on BAL and lung neutrophils influx. The Celecoxib COX-2 inhibitor reduced RTHR and the number of cells in BAL and lung neutrophils influx of rats treated with LPS. Celecoxib and LLLT reduced the PGE(2) and TXA(2) levels in the BAL of LPS-treated rats. Our results demonstrate that LLLT produced anti-inflammatory effects on RTHR, BAL and lung neutrophils influx in association with inhibition of COX-2-derived metabolites.

Analgesic Effect of He-Ne (632.8 nm) Low-Level Laser Therapy on Acute Inflammatory Pain

OBJECTIVE

The aim of this study was to evaluate the analgesic effect of the low level laser therapy (LLLT) with a He-Ne laser on acute inflammatory pain, verifying the contribution of the peripheral opioid receptors and the action of LLLT on the hyperalgesia produced by the release of hyperalgesic mediators of inflammation.

BACKGROUND DATA

All analgesic drugs have undesired effects. Because of that, other therapies are being investigated for treatment of the inflammatory pain. Among those, LLLT seems to be very promising.

MATERIAL AND METHODS

Male Wistar rats were used. Three complementary experiments were done. (1) The inflammatory reaction was induced by the injection of carrageenin into one of the hind paws. Pain threshold and volume increase of the edema were measured by a pressure gauge and plethysmography, respectively. (2) The involvement of peripheral opioid receptors on the analgesic effect of the laser was evaluated by simultaneous injection of carrageenin and naloxone into one hind paw. (3) Hyperalgesia was induced by injecting PGE2 for the study of the effect of the laser on the sensitization increase of nociceptors. A He-Ne laser (632.8 nm) of 2.5 J/cm2 was used for irradiation.

RESULTS

We found that He-Ne stimulation increased the pain threshold by a factor between 68% and 95% depending on the injected drug. We also observed a 54% reduction on the volume increase of the edema when it was irradiated.

CONCLUSION

He-Ne LLLT inhibits the sensitization increase of nociceptors on the inflammatory process. The analgesic effect seems to involve hyperalgesic mediators instead of peripheral opioid receptors.

Laser Therapy on Arthritis Induced by Urate Crystals

OBJECTIVE

We aimed to evaluate low-power laser therapy efficacy on fibrinogen (PF) in the plasma of rats with arthritis induced by urate crystals. In addition, anatomopathological (AP) studies were carried out.

BACKGROUND DATA

Raised blood uric acid may form microscopic crystals in the joint. These crystals set up the inflammation called "acute gouty arthritis."

METHODS

Two mg of uric acid were injected in both joints of the lower limbs of rats over 2 days. A group was treated with He-Ne laser (6 mW) on the injected joints during 3 consecutive days. After 96 h of the first injection, animals were sacrificed to determine fibrinogen by spectrophotometry. Sections from the lower limbs were used for AP studies.

RESULTS

A statistically significant increase (p < 0.001) in plasma fibrinogen levels was observed in the group injected with urates, when compared to both control group and the laser-treated group. The AP observed in the untreated group showed an intense fibroblastic proliferation and chronic inflammation. In the group treated with laser no inflammatory reaction was observed.

CONCLUSIONS

Laser therapy has an anti-inflammatory effect in arthropathy induced in rats injected with urates, determined by fibrinogen levels and by histological involution.

A histologic assessment of the influence of low-intensity laser therapy on wound healing in steroid-treated animals

OBJECTIVE

The aim of the present study was to evaluate the effect of low-intensity laser therapy on the wound healing process treated with steroid.

BACKGROUND DATA

Various biological effects have been associated with low-level laser therapy (LLLT).

MATERIALS AND METHODS

Forty-eight rats were used, and after execution of a wound on the dorsal region of each animal, they were divided into 4 groups (n = 12), receiving the following treatments: G1 (control), wounds and animals received no treatment; G2, wounds were treated with LLLT; G3, animals received an intraperitoneal injection of steroid dosage (2 mg/kg of body weight); G4, animals received steroid and wounds were treated with LLLT. The laser emission device used was a GaAIAs (904 nm), in a contact mode, with 2.75 mW gated with 2.900 Hz during 120 sec (33 J/cm(2)). After the period of 3, 7, and 14 days, the animals were sacrificed and the parts sent to histological processing and dyed using hematoxylin and eosin (HE) and Masson trichromium (MT) techniques.

RESULTS

The results have shown that the wounds treated with steroid had a delay in healing, while LLLT accelerated the wound healing process. Also, wounds treated with laser in the animals treated with steroid presented a differentiated healing process with a larger collagen deposition and also a decrease in both the inflammatory infiltrated and the delay on the wound healing process.

CONCLUSION

LLLT accelerated healing, caused by the steroid, acting as a biostimulative coadjutant agent, balancing the undesirable effects of cortisone on the tissue healing process.

Effects of different protocol doses of low power gallium–aluminum–arsenate (Ga–Al–As) laser radiation (650 nm) on carrageenan induced rat paw ooedema

The purpose of the present study was to investigate the effect of the low power laser therapy on the acute inflammatory process. Male Wistar rats were used. The rat paw oedema was induced by sub-plantar injection of carrageenan, the paw volume was measured before and 1, 2, 3 and 4 h after the injection using a hydroplethysmometer. To investigate the mechanism action of the Ga-Al-As laser on inflammatory oedema, parallel studies were performed using adrenallectomized rats or rats treated with sodium diclofenac. Different laser irradiation protocols were employed for specific energy densities (EDs), exposure times and repetition rates. The rats were irradiated with the Ga-Al-As laser during 80 s each hour. The ED that produced an anti-inflammatory effect were 1 and 2.5 J/cm(2), reducing the oedema by 27% (P<0.05) and 45.4% (P<0.01), respectively. The ED of 2.5 J/cm(2) produced anti-inflammatory effects similar to those produced by the cyclooxigenase inhibitor sodium diclofenac at a dose of 1 mg/kg. In adrenalectomized animals, the laser irradiation failed to inhibit the oedema. Our results suggest that low power laser irradiation possibly exerts its anti-inflammatory effects by stimulating the release of adrenal corticosteroid hormones.

Usefulness of low-level laser for control of painful stomatitis in patients with hand-foot-and-mouth disease

OBJECTIVE

The aim of this study was to evaluate the usefulness of low-level laser therapy (LLLT) for the control of painful stomatitis in patients with hand-foot-and-mouth disease (HFMD).

BACKGROUND DATA

LLLT has been successfully applied to various painful oral mucosal diseases, although there have been few reports on LLLT for HFMD patients.

MATERIALS AND METHODS

Through a randomized double-blind placebo controlled trial, the painful period of HFMD stomatitis was compared between the LLLT group (n=11) and the placebo LLLT one (n=9), which had similar clinical backgrounds. The LLLT parameters supplied were as follows: wavelength of 830 nm, power of 30 mW, frequency of 30 Hz, and energy output of 1.1 J/cm2. Acceptability and safety of the treatment were also evaluated.

RESULTS

The painful period was shorter in the LLLT group (4.0 +/- 1.3 days) than in the placebo LLLT one (6.7 +/- 1.6 days) with a statistically significant difference (p<0.005). The treatment was judged acceptable for 90.0% (18 of 20) of patients. No adverse events were observed in any cases.

CONCLUSION

LLLT is a useful method to control HFMD stomatitis by shortening the painful period, with its high acceptability and lack of adverse events.

Spectral response for laser enhancement in hepatic regeneration for hepatectomized rats

BACKGROUND AND OBJECTIVES

The low intensity laser therapy (LILT) has been widely used in all medical fields due to its therapeutic effects in reparative process, pain relief, and biostimulation. Even though there is a therapeutic window of wavelengths for clinical application, little has been done concerning the frequency spectrum response to biological effects. In this work, we investigate the dependence of different wavelengths irradiation in the enhancement of the tissue regeneration after partial hepatectomy in Wistar rats.

STUDY DESIGN/MATERIALS AND METHODS

The proliferating cell nuclear antigen (PCNA) labeling index and the respiratory control (oxygen consumption in extracted mitochondria) were the tests used to evaluate the liver regeneration after laser irradiation with different wavelengths.

RESULTS AND CONCLUSIONS

The results show a correlated spectral response that can be explained based on the combined effect of light penetration on biological tissues and the biomolecular excitation efficiency for each wavelength used.

He-Ne laser on microcrystalline arthropathies

OBJECTIVE

The objective of this work is to assess the anti-inflammatory capacity of He-Ne laser therapy as determined by the plasmatic levels of inflammatory markers, fibrinogen, and TNFalpha and by histopathological study in rats with arthropathy induced by calcium pyrophosphate crystals.

BACKGROUND DATA

Microcrystalline arthropathies are a group of diseases characterized by the deposit of different crystals in joints.

MATERIALS AND METHODS

Two milligrams of dicalcium pyrophosphate crystals (DCPP) were injected in both joints of the lower limbs of rats during 2 days. A group was treated with laser of He-Ne (6 mW) on the injected joints during 3 consecutive days. After 96 h of the first injection, animals were sacrificed to determine TNFalpha using the ELISA method and fibrinogen was assessed using spectrophotometry. Sections from the lower limbs were used for histopathology.

RESULTS

A statistically significant increase (p < 0.001) in plasma fibrinogen levels and TNFalpha was noted between the control group and the laser-treated group. The histological transversal section of a posterior limb joint of a rat injected with DCPP showed fibroadipose tissue with diffuse chronic infiltrate. The histopathology of the group of rats injected with DCPP and subsequently treated with He-Ne laser showed no inflammatory response.

CONCLUSION

He-Ne laser treatment in the microcrystalline arthropathy induced in rats by DCPP injection might have an antiinflammatory effect, evaluated by fibrinogen plasma levels and TNF-alpha (inflammatory markers) and by the histopathology regressive process.

Hyperfibrinogenemia in rats treated with meloxicam

Fibrinogen secretion is mediated by prostaglandin biosynthesis and is considered a risk factor for cardiovascular disease. Since meloxicam produces inhibition of prostaglandin biosynthesis it may help to normalize hyperfibrinogenemia. We investigated the pharmacological effect of meloxicam on fibrinogen levels and the possible regression of histopathological lesions of thoracic aorta. Rats were subjected to multiple injuries (MI) in the form of laparotomies (Lx) during a 30 day period (1/week). Meloxicam 0.065 mg/kg/day (per rat) was administered orally immediately after the third Lx in multiple injury animals during a ten day period. Blood was obtained 72 hours after the last injury in all groups. Fibrinogen was measured by spectrophotometry and the values were expressed in mg/dL. A statistically significant increment of fibrinogen was observed when comparing uninjured animals (control) (208.7+/-6.0) with the multiple injury group (336.6+/-7.5) (P<0.001). Fibrinogen decreased to the control value in the meloxicam group (198+/-8.7). Histopathological lesions were similar in the MI and meloxicam groups, showing endothelial denudation and intima enlargement from the thoracic aorta in 96% of the slices studied. The decrease in fibrinogen in the meloxicam group would be due to cyclooxygenase-2 (Cox-2) selective inhibition, even though the histopathological lesions did not regress.

Hairless mouse epidermal antioxidants and lipid peroxidation assessed by He-Ne laser

BACKGROUND AND OBJECTIVE

To evaluate the possibility of oxygen radical damage in the skin after He-Ne laser irradiation according to dose intensity and time.

STUDY DESIGN/MATERIALS AND METHODS

The He-Ne laser (lambda = 632.8, 10 mW) was used on the skin of mice with 1, 3, and 5 joule (J/cm2) dose rates for 1, 5, and 7 days in each case, and the results were compared with normal and anesthetic nonirradiated skins. The efficacy was determined by the formation of thiobarbituric acid-reactive substances (TBARS) in a 10-minute period and expressed as a concentration of malondialdehyde (MDA) from the lipid peroxidation of epidermal tissue, and total superoxide dismutases (SODs) and catalase activities, correlated with histologic biopsies.

RESULTS

Data from epidermal SODs, catalase activity and the degree of lipid peroxidation at low-power radiation showed that repeated exposure had led to the induction of free radical damage and of epidermal changes as confirmed by microscopic study. The application of the He-Ne laser at 1, 3, and 5 J intensity for 5 days caused a gradual increase in the SODs and catalase activities, while the levels of TBARS were slightly decreased in the mouse epidermis. However, these patterns were reversed after 3 and 5 J irradiations for 5 and 7 days laser treatment. Furthermore, microscopic examinations revealed that the laser-irradiated skin changed the release of stratum granule from epidermis to hair follicle, and produced blood vessel thrombosis of the dermal capillary plexus.

CONCLUSION

The presence of lipid peroxidation in the hairless mouse skin after exposure to He-Ne laser energy intensity of over 3 J for over 5 days was demonstrated. This lipid peroxidation could have been generated from oxygen free radicals. The histologic and oxidative enzymatic correlations on lipid peroxidation in the skin have provided a better understanding of He-Ne laser therapy-tissue interactions. It is possible to take advantage of these findings to evaluate pathologic skin conditions and effective laser dosage more efficiently.

Effect of low-level laser radiation on some rheological factors in human blood: an in vitro study

OBJECTIVE

The purpose of this study was to investigate the in vitro effects of low-level laser radiation (LLLR) on some rheological factors of the human blood, such as complete blood count (CBC) parameters and blood sedimentation rate (BSR). We were mainly concerned with the alterations caused by LLLR action on blood cells (erythrocytes and leukocytes) of fresh blood obtained from apparently healthy adult patients. We used low doses ranging between 0.80 J x cm(-3) and 4.40 J x cm(-3), at the very low-power densities of the laser radiation, so as not to damage the cell structure and not to alter in an undesired manner their functions.

METHODS

Blood samples were taken from 22 volunteers. Where health problems existed, they were indicated for each case. The parameters mentioned above were measured before (control samples) and after irradiation. A He-Ne laser, operating in continuous wave, as a radiation source (632.8 nm, 1 mW, intensity of 8 x 10(-2) W x sr(-1), mean power density incident on blood samples around 30 mW x cm(-2), beam spot diameter 2 mm) was used. The measurements were performed immediately after irradiation. Only the erythrocyte complex was irradiated. EDTA anticoagulant was used.

RESULTS

The measurements using a computerized hemoanalyzer type SERONO showed significant differences between control and irradiated blood samples concerning the following parameters: RBC (in 22% of cases), HGB (47.3%), HCT (84.2%), RDW (11%), PLT (5.26%), MPV (33.3%), WBC (5.26%), MONO (26.3%), and GRAN (63.15%). In the case of BSR (44%), the significant differences were noticed especially in the cases of patients suffering from some acute or chronic diseases. Nonsignificant differences were noticed in the cases of MCV, MCH, MCHC, RDW, and LYMPH.

CONCLUSIONS

This study has shown that LLLR, even though used at low doses and low power densities, produced some changes of the rheological factors of the blood, as follows: a revitalizing and regenerating effect on mitosis stimulation and a nondamaging and biostimulating effect on the cell membrane (by keeping unmodified MCV, MCH, and MCHC). In 3 cases out of 22, hemolysis (complete or partially) occurred, but we are not yet sure whether this was caused by laser exposure or by certain environmental physical factors.