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-1ß, IL-10, and TGF-ß 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-ß and IL-1ß release. In conclusion, we believe that pulsed LLLT worked effectively as a therapy to reestablish the tendon integrity after rupture.

Effect of phototherapy with light-emitting diodes (890 nm) on tendon repair: an experimental model in sheep.

The effect of phototherapy with 890-nm light-emitting diodes (LEDs) on the healing of experimentally induced tendinitis in sheep was evaluated in this study. Partial tenotomies measuring 0.2 cm wide × 0.5 cm long were performed on the second third of the superficial digital flexor tendons of 10 healthy sheep. The animals were divided into two groups: "treated" (TG), treated with LEDs at the aforementioned wavelength, and "control" (CG), a control group treated with a placebo. Kinesiotherapy, which consisted of 5-min walks on grassy ground, was performed on both groups. B-mode and power Doppler ultrasonographies (US) were performed to evaluate the tendon healing process during the first 14 days after surgery and on the 21st and 28th postoperative days. Biopsies were performed on day 28 for the histopathological assessment of neovascularisation and the pattern of the tendon fibres. The absence of lameness and a significant improvement (p < 0.05) in the sensitivity to pain during palpation were observed in the treated group. Furthermore, a significant reduction in oedema and an increased number of vessels (p < 0.05) were observed in this group with the B-mode and power Doppler US, respectively. No significant difference in the evolution of the lesion was found. There was a histological difference (p < 0.05) in neovascularisation in the treated group. Phototherapy with 890-nm light-emitting diodes decreases the inflammatory process.

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-1ß, IL-6, TGF-ß 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-ß expression after tendinitis, respectively, when compared to tendinitis groups: IL-6, COX-2, and TGF-ß. The LLLT not altered IL-1ß 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.

Use of lectins to evaluate the effects of GaAs softlaser on dog tendon.

1. Lectins labeled with colloidal gold particles were used for the ultrastructural evaluation of the biological effects of GaAs softlaser irradiation on the healing of dog tendon wounds. 2. Six dogs were submitted to tenotomy and tenorrhaphy on the right and left hind legs. All animals received laser irradiation (4 J/cm2) daily for ten days only on the left leg, and the right leg of the same animal was used as control. Biopsies were taken 11, 22 and 40 days after surgery. 3. Laser-irradiated and control tendon tissues were embedded in L.R. White resin and thin sections were incubated in the presence of gold-labeled Arachis hypogaea (PNA), Canavalia ensiformes (Con A) and Triticum vulgare (WGA). 4. In general, the control and laser-irradiated tissues presented homogeneous and similar labelling of heterochromatin, rough endoplasmic reticulum and extracellular matrix. 5. We conclude that GaAs softlaser irradiation does not produce significant changes in the glycosylation of healing tendons.

Use of lectins to evaluate the effects of GaAS softlaser on dog tendon

1. Lectins labeled with colloidal gold particles were used for the ultrastructural evaluation of the biological effects of GaAs softlaserirradiation on the healing of dog tendon wounds. 2. Six dogs were submitted to tenotomy and tenorrhaphy on the right and left hind legs. All animals received laser irradiation (4J/cm²) daily for ten days only on the left leg, and the right leg of the same animal was used as control. Biopsies were taken 11, 22 and 40 days after surgery. 3. Laser-irradiated and control tendon tissues were embedded in L.R. White resin and thin section were incubated in the presence of gold-labeled Arachis hypogaea (PNA), Canavalia ensiformes (Con A) and Triticum vulgare (WGA). 4. In general, the control and laser-irradiated tissues presented homogeneous and similar labelling of heterochromatin, rough endoplasmic reticulum and extracellular matrix. 5. We conclude that GaAs softlaser irradiation does not produce significant changes in the glycosylation of healing tendons