Pulsed Low-level Laser Therapy Research Articles

Comparison of pulsed low level laser therapy and pulsed ultrasound therapy in the Treatment of episiotomy

Comparison of pulsed low level laser therapy and pulsed ultrasound therapy in the Treatment of episiotomy

Low-level laser therapy modulates pro-inflammatory cytokines after partial tenotomy.

Tendon injuries give rise to substantial morbidity, and current understanding of the mechanisms involved in tendon injury and repair is limited. This lesion remains a clinical issue because the injury site becomes a region with a high incidence of recurrent rupture and has drawn the attention of researchers. We already demonstrated that low-level laser therapy (LLLT) stimulates the synthesis and organization of collagen I, MMP-9, and MMP-2 and improved the gait recovery of the treated animals. The aim of this study was to evaluate the effects of LLLT in the nitric oxide and cytokines profile during the inflammatory and remodeling phases. Adult male rats were divided into the following groups: G1--intact, G2-- injured, G3--injured + LLLT (4 J/cm(2) continuous), G4--injured + LLLT (4 J/cm(2)-20 Hz--pulsed laser). According to the analysis, the animals were euthanized on different dates (1, 4, 8, or 15 days after injury). ELISA assay of TNF-α, IL-1β, IL-10, and TGF-β was performed. Western blotting of isoform of nitric oxide synthase (i-NOS) and nitric oxide dosage experiments was conducted. Our results showed that the pulsed LLLT seems to exert an anti-inflammatory effect over injured tendons, with reduction of the release of proinflammatory cytokines, such as TNF-α and the decrease in the i-NOS activity. Thanks to the pain reduction and the facilitation of movement, there was a stimulation in the TGF-β and IL-1β release. In conclusion, we believe that pulsed LLLT worked effectively as a therapy to reestablish the tendon integrity after rupture.

Short-term effects of extremely low-frequency pulsed electromagnetic field and pulsed low-level laser therapy on rabbit model of corneal alkali burn

This study was conducted to investigate the effect of combining extremely low frequency–pulsed electromagnetic field (ELF-PEMF) and low-level laser therapy (LLLT) on alkali-burned rabbit corneas. Fifty alkali-burned corneas of 50 rabbits were categorized into five groups: ELF-PEMF therapy with 2 mT intensity (ELF 2) for 2 h daily; LLLT for 30 min twice daily; combined ELF-PEMF and LLLT (ELF + LLLT); medical therapy (MT); and control (i.e., no treatment). Clinical examination and digital photography of the corneas were performed on days 0, 2, 7, and 14. After euthanizing the rabbits, the affected eyes were evaluated by histopathology. The clinical and histopathologic results were compared between the groups. On days 7 and 14, no significant difference in the corneal defect area was evident between the ELF, LLLT, ELF + LLLT, and MT groups. Excluding the controls, none of the study groups demonstrated a significant corneal neovascularization in both routine histopathology and immunohistochemistry for CD31. Keratocyte loss was significantly higher in the MT group than in the ELF, LLLT, and ELF + LLLT groups. Moderate to severe stromal inflammation in the LLLT group was comparable with that in the MT group and was significantly lower than that in the other groups. In conclusion, combining LLLT and ELF was not superior to ELF alone or LLLT alone in healing corneal alkali burns. However, given the lower intensity of corneal inflammation and the lower rate of keratocytes loss with LLLT, this treatment may be superior to other proposed treatment modalities for healing alkali-burned corneas.

Histological and gene expression analysis of the effects of pulsed low-level laser therapy on wound healing of streptozotocin-induced diabetic rats

Diabetes mellitus (DM) is associated with poor wound healing. Studies have shown accelerated wound healing following pulsed low-level laser therapy (LLLT) in non-diabetic animals. The present study aims to evaluate the effect of pulsed LLLT on wound healing in streptozotocin-induced diabetic (STZ-D) rats. We divided 48 rats into two groups of non-diabetic and diabetic. Type 1 DM was induced in the diabetic rat group by injections of STZ. Two, full-thickness skin incisions were made on the dorsal region of each rat. One month after the STZ injection, wounds of the non-diabetic and diabetic rats were submitted to a pulsed, infrared 890-nm laser with an 80-Hz frequency and 0.2 J/cm(2) for each wound point. Control wounds did not receive LLLT. Animals were sacrificed on days 4, 7, and 15 post-injury for histomorphometry and reverse transcription polymerase chain reaction (RT-PCR) analyses of basic fibroblast growth factor (bFGF) gene expression. Pulsed LLLT significantly increased the numbers of macrophages, fibroblasts, and blood vessel sections compared to the corresponding control groups. Semi-quantitative analysis of bFGF gene expression at 48 h post-injury revealed a significant increase in gene expression in both non-diabetic and diabetic rats following LLLT (the ANOVA test). Pulsed LLLT at 0.2 J/cm(2) accelerated the wound healing process in both non-diabetic and diabetic rats as measured by histological characteristics and semi-quantitative bFGF gene expression.

Effects of pulsed infra-red low level-laser irradiation on mast cells number and degranulation in open skin wound healing of healthy and streptozotocin-induced diabetic rats

Introduction: Low-level laser therapy (LLLT) has been reported to be capable of changing mast cell numbers and degranulation in experimental wounds. Objective: We conducted a study on the influence of pulsed LLLT on mast cells in wounds of non-diabetic and diabetic rats. Methods: Thirty-six rats were randomly divided into non-diabetic and diabetic groups. Type 1 diabetes milletes (DM) was induced in rats of the diabetic group by administration of streptozotocin (STZ). We inflicted two wounds in each rat. The first wound in both non-diabetic and diabetic groups was treated with an 890-nm laser, having pulse frequency of 80 Hz and energy density of 0.2 J/cm2. Mast cell numbers and degranulation of all subgroups were assessed at 4, 7, and 15 days after the infliction of the wounds. Results and conclusion: According to the paired t-test, the total number of laser-treated mast cells was significantly higher than that of the placebos in the non-diabetic groups on days 4 and 15. The total number of laser-treated mast cells was significantly higher than that of the placebos in the diabetic groups on days 4 and 15. The number of granulated mast cells was significantly higher than that of degranulated mast cells for all laser-treated mast cells and placebo mast cells of the non-diabetic and diabetic groups.

Low-Level Laser Therapy with a Pulsed Infrared Laser Accelerates Second-Degree Burn Healing in Rat: A Clinical and Microbiologic Study

This study was carried out to investigate the influence of pulsed-wave low-level laser therapy (LLLT) on the healing of a deep second-degree burn model in rat. Review of literature indicates that LLLT has a biostimulatory effect on wound healing; however, no clear recommendation can yet be made. Two deep second-degree burns were made in the skin of 67 rats. Rats were divided into four groups. In the first group (control), the proximal burn were received LLLT with shot down laser; in the second and third groups, proximal burns were treated with a 3,000-Hz pulsed infrared diode laser with 2.3 and 11.7 J/cm(2) energy densities, respectively. In the fourth group, the proximal burns were treated topically with 0.2% nitrofurazone. The distal burn of all groups was considered the control burn. The response to treatment was assessed both microbiologically and macroscopically. The incidence of Staphylococcus aureus decreased significantly in group 3 in comparison with group 1 on day 28 (χ(2) test, p = 0.05). Analysis of variance showed that LLLT with 11.7 J/cm (2) significantly increased the wound-closure rate at 2 weeks (0.915 ± 0.310) and 3 weeks (0.677 ± 0.397) after burning compared with placebo burns (1.413 ± 0.319; 1.116 ± 0.436, respectively) ANOVA-LSD test, p = 0.045 and p = 0.046 respectively. Independent sample t tests showed that LLLT with 11.7 J/cm (2) significantly increased the wound-closure rate at 4 weeks after burning (0.211 ± 0.146) compared with the control burns (0.707 ± 0.480) p = 0.039. Pulsed LLLT with 11.7 J/cm(2)/890 nm of a deep second-degree burn model in rat significantly increased the rate of wound closure compared with control burns.

Effects of 780-nm Low-Level Laser Therapy with a Pulsed Gallium Aluminum Arsenide Laser on the Healing of a Surgically Induced Open Skin Wound of Rat

The aim of the present investigation is to evaluate the effects of a 780-nm low-level laser on open skin wound healing. Optimal parameters of low-level laser therapy (LLLT) for wound healing are discussed. One full-thickness skin wound was surgically induced in the dorsum skin of 30 rats. The rats were divided into two groups. Rats in the experimental group were daily treated with a gallium aluminum arsenide (GaAlAs) laser (2 J/cm(2), lambda = 780 nm, pulse frequency of 2336 Hz). Rats in the sham-exposed group received LLLT with switched off equipment. After 4, 7, and 15 days, wounds were checked by histological and biomechanical methods. Data were analyzed by the Mann-Whitney U-test. Fibroblasts, endothelium of blood vessels, blood vessel sections, and maximum stress were significantly increased, whereas macrophages were significantly decreased, compared with those of the sham-exposed group. Pulsed LLLT with a 780-nm GaAlAs laser significantly accelerates the process of healing of surgically induced, full-thickness skin wounds in rat.

Low-level laser therapy with pulsed infrared laser accelerates third-degree burn healing process in rats

This study investigated the influence of pulsed low-level laser therapy (LLLT) on the healing of a third-degree burn in a rat model. Two third-degree burns (distal and proximal) were made in the skin of 74 rats. Rats were divided into four groups. In group 1, the distal burn received LLLT with laser switched off; in groups 2 and 3, distal burns were treated with a 3,000 Hz-pulsed infrared diode laser with 2.3 and 11.7 J/cm(2) energy densities, respectively. In group 4, the distal burns were treated topically with 0.2% nitrofurazone. The proximal burn of all groups was considered a control burn. We assessed the response to treatment both microbiologically and macroscopically. The chi-square test showed that the incidence of Staphylococcus epidermidis, Lactobacillus, and diphtheria decreased significantly in laser-treated groups compared with other groups. Independent sample t-test showed that LLLT with 11.7 J/cm(2) energy density significantly increased wound-closure rate at 3 and 4 weeks after burning compared with their relevant control burns (p = 0.018 and p = 0.01, respectively). Pulsed LLLT with 11.7 J/cm(2)/890 nm of a third-degree burn in a rat model significantly increased wound-closure rate compared with control burns.