The Effects of 660 nm and 780 nm Laser Irradiation on Viability of Random Skin Flap in Rats

Cury, Vivian; Bossini, Paulo Sérgio; Fangel, Renan; Crusca, Jaqueline de Sousa; Rennó, Ana Cláudia Muniz; Parizotto, Nivaldo Antônio

doi:10.1089/pho.2008.2383

Cited by 19 publications

(23 citation statements)

References 22 publications

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“…The mostly feared of these events is skin flap necrosis, caused by inadequate blood flow [1–4]. Under ideal conditions, hypoxia resulting from improper tissue perfusion should lead to an adaptive response, inducing angiogenesis, that is, the formation of new vessels from pre-existing ones, a necessary step to ensure adequate blood supply during the healing process [5–7].…”

Section: Introductionmentioning

confidence: 99%

Low level laser therapy increases angiogenesis in a model of ischemic skin flap in rats mediated by VEGF, HIF-1α and MMP-2

Cury

Moretti

Assis

et al. 2013

Journal of Photochemistry and Photobiology B: Biology

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102

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It is known that low level laser therapy is able to improve skin flap viability by increasing angiogenesis. However, the mechanism for new blood vessel formation is not completely understood. Here, we investigated the effects of 660 nm and 780 nm lasers at fluences of 30 and 40 J/cm2 on three important mediators activated during angiogenesis. Sixty male Wistar rats were used and randomly divided into five groups with twelve animals each. Groups were distributed as follows: skin flap surgery non-irradiated group as a control; skin flap surgery irradiated with 660 nm laser at a fluence of 30 or 40 J/cm2 and skin flap surgery irradiated with 780 nm laser at a fluence of 30 or 40 J/cm2. The random skin flap was performed measuring 10 × 4 cm, with a plastic sheet interposed between the flap and the donor site. Laser irradiation was performed on 24 points covering the flap and surrounding skin immediately after the surgery and for 7 consecutive days thereafter. Tissues were collected, and the number of vessels, angiogenesis markers (vascular endothelial growth factor, VEGF and hypoxia inducible factor, HIF-1α) and a tissue remodeling marker (matrix metalloproteinase, MMP-2) were analyzed. LLLT increased an angiogenesis, HIF-1α and VEGF expression and decrease MMP-2 activity. These phenomena were dependent on the fluences, and wavelengths used. In this study we showed that LLLT may improve the healing of skin flaps by enhancing the amount of new vessels formed in the tissue. Both 660 nm and 780 nm lasers were able to modulate VEGF secretion, MMP-2 activity and HIF-1α expression in a dose dependent manner.

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Section: Introductionmentioning

confidence: 99%

Low level laser therapy increases angiogenesis in a model of ischemic skin flap in rats mediated by VEGF, HIF-1α and MMP-2

Cury

Moretti

Assis

et al. 2013

Journal of Photochemistry and Photobiology B: Biology

Self Cite

160

102

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“…Considering the results reported by Cury et al (13), it may be suggested that the lack of influence of laser irradiation on the viability of skin flaps occurred due to the correlation of the distance between the irradiated points and the energetic magnitude irradiated in each point. Additionally, Cury et al (13) took advantage of a significantly higher number of suture points than those used in the surgical technique performed in other studies, which could have led to more tension on the flap and possible complications to the local microcirculation.…”

Section: Discussionmentioning

confidence: 91%

“…All of these factors may be associated with increased viability of skin flaps. However, some studies have shown that LLLT was not effective at improving the viability of random skin flaps in rats (3,13).…”

Section: Discussionmentioning

confidence: 99%

Inhibitory effects of low-level laser therapy on skin-flap survival in a rat model

Baldan¹,

Masson²,

Esteves³

et al. 2015

CAN J PLAST SURG

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L ow-level laser therapy (LLLT) has been investigated as a noninvasive and sterile alternative for improvement of microcirculation and, consequently, increasing the viability of ischemic skin flaps (1-13). It is known as an athermal treatment modality due to the relatively low doses and low powers that are unable to promote any change in tissue temperature.Several studies have demonstrated the efficacy of LLLT in accelerating the healing process, the promotion of analgesia, and an increase in microcirculation and capillarity (5,6,11). Skin flaps may progress to necrosis due to intrinsic and extrinsic factors that compromise local microcirculation (14); LLLT has been used to increase skin flap viability.Several parameters must be considered when applying LLLT. These include wavelength, output power, emission mode, spot size and shape of the beam, irradiance, energy density, irradiation time, application technique, energy per point and total energy delivered to the tissue (9). Although all of these parameters appear to be important in modulating physiological and therapeutic responses, wavelength, energy and application time have been suggested by the World Association for Laser Therapy (WALT) as key factors (15). Both infrared (1,2,4,6,11) and red (5,8-10) lasers have been used to increase skin flap viability. Despite the positive results demonstrated with both types of lasers, some studies suggest that lasers with wavelengths in the red spectrum are more effective at increasing skin flap viability (16). The energy used in previous studies assessing the effects of red lasers in dorsal random skin flaps ranged from 0.06 J to 1.44 J per point (3,9,5,10,12). Energies <0.3 J were ineffective (3,9), whereas energies from 0.3 J to 1.44 J (5,10,12) increased skin flap survival. According to Arndt-Schulz' law, very low doses are ineffective, and intense stimuli may result in negative responses in tissue physiology. It appears that energies from 0.3 J to 1.44 J are in the therapeutic window for improving skin flap survival. Nevertheless, to the best of our knowledge, no studies have demonstrated an inhibitory effect on skin flap survival using higher energies of LLLT. Thus, the present study aimed to test an energy greater than those proven to be effective. Accordingly, the objective of the present study was to investigate the inhibitory effect of LLLT (λ=670 nm) on the viability of random skin flaps in rats when irradiated with 2.79 J of energy at each point. METHODS Study designThe present study was approved by the Ethics and Research Committee of Paulista University (São Paulo, Brazil) under protocol number CEP 008/11.The present analysis was an experimental, interventional, randomized study with a blinded assessor. All animals received humane care in strict compliance with the Ethical Guidelines for Animal Experiments, Council for International Organizations of Medical Sciences, Standards of Brazilian Science Society for Laboratory Animals, and current national legislation on Procedures for the Scientific Use of Anima...

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“…Several studies have investigated the effects of low-level laser therapy on the viability of skin flaps [4,[7][8][9][29][30][31][32][33][34][35][36]. Wavelengths in the visible red light spectrum (632.8, 660 and 670 nm) [7,29,[31][32][33][34][35][36] and infrared spectrum (780 and 830 nm) [4,8,9,34,36] are the most commonly used.…”

Section: Discussionmentioning

confidence: 99%

“…Wavelengths in the visible red light spectrum (632.8, 660 and 670 nm) [7,29,[31][32][33][34][35][36] and infrared spectrum (780 and 830 nm) [4,8,9,34,36] are the most commonly used. However, all the above-mentioned studies used different dosimetric parameters in the formulation of applied doses.…”

Section: Discussionmentioning

confidence: 99%

Low-level laser irradiation, cyclooxygenase-2 (COX-2) expression and necrosis of random skin flaps in rats

et al. 2011

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Skin flaps are still a matter of concern among surgeons, as failures can occur leading to flap necrosis. However, low-level laser irradiation has been reported as an effective tool to improve the viability of ischemic flaps, yet its mechanisms of action remain unclear. We investigated the effect of low-level laser irradiation on the viability of random skin flaps in rats and determined COX-2 expression in the flap pedicle. The study animals comprised 24 EPM-1 Wistar rats which were randomly allocated into three equal groups. A cranially based dorsal random skin flap measuring 10 × 4 cm was created in all the animals. In one group, laser irradiation was simulated (sham group), and in the other two groups the animals were irradiated at 12 points with 0.29 J at 20 mW (energy density 10.36 J/cm(2), irradiance 0.71 W/cm(2)), or with 7.3 J at 100 mW (energy density 260.7 J/cm(2), irradiance 3.57 W/cm(2)). These procedures were applied to the cranial half of the flap immediately after surgery and were repeated on days 2 and 5 after surgery. The percentage necrotic area was determined on day 7 after surgery by the paper template method. The immunohistochemical expression of COX-2 in the samples was given scores from 0 to 3. The necrotic area was smaller in group irradiated at 7.3 J compared to sham-treated group and to the group irradiated at 0.29 J (P < 0.05); there was no difference between the sham-treated group and group irradiated at 0.29 J. COX-2 expression was lower in the group irradiated at 7.3 J than in the sham-treated group and the group irradiated at 0.29 J (P < 0.001). Low-level laser therapy was effective in decreasing random skin flap necrosis in rats using a laser energy of 7.30 J per point. Laser irradiation also decreased the expression of COX-2 in the flap pedicle.

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The Effects of 660 nm and 780 nm Laser Irradiation on Viability of Random Skin Flap in Rats

Abstract: This present study showed that 660 nm and 780 nm lasers at doses of 30 and 40 J/cm(2) were not effective for decreasing the necrotic area of the skin flaps in rats.

Cited by 19 publications

References 22 publications

Low level laser therapy increases angiogenesis in a model of ischemic skin flap in rats mediated by VEGF, HIF-1α and MMP-2

Low level laser therapy increases angiogenesis in a model of ischemic skin flap in rats mediated by VEGF, HIF-1α and MMP-2

Inhibitory effects of low-level laser therapy on skin-flap survival in a rat model

Low-level laser irradiation, cyclooxygenase-2 (COX-2) expression and necrosis of random skin flaps in rats

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