Red LLLT and LED demonstrated expressive results in angiogenesis. Light coherence was shown not to be essential to angiogenesis. However, further studies are needed in order to investigate the photobiomodulatory effects of LED in relation to LLLT in various biological tissues.

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Reduced aerobic fitness is associated with an increased risk of cardiovascular diseases among the older population. The aim of this study was to investigate the effects of LED irradiation (850 nm) applied during treadmill training on the maximal exercise tolerance in postmenopausal women. At the beginning of the study, 45 postmenopausal women were assigned randomly to three groups, and 30 women completed the entire 6 months of the study. The groups were: (1) the LED group (treadmill training associated with phototherapy, n = 10), (2) the exercise group (treadmill training, n = 10), and (3) the sedentary group (neither physical training nor phototherapy, n = 10). The training was performed for 45 min twice a week for 6 months at intensities between 85% and 90% maximal heart rate (HRmax). The irradiation parameters were 39 mW/cm(2), 45 min and 108 J/cm(2). The cardiovascular parameters were measured at baseline and after 6 months. As expected, no significant differences were found in the sedentary group (p ≥ 0.05). The maximal time of tolerance (Tlim), metabolic equivalents (METs) and Bruce stage reached significantly higher values in the LED group and the exercise group (p < 0.01). Furthermore, the HR, double product and Borg score at isotime were significantly lower in the LED group and in the exercise group (p < 0.05). However, the time of recovery showed a significant decrease only in the LED group (p = 0.003). Moreover, the differences between before and after training (delta values) for the Tlim, METs and HR at isotime were greater in the LED group than in the exercise group with a significant intergroup difference (p < 0.05). Therefore, the infrared LED irradiation during treadmill training can improve maximal performance and post-exercise recovery in postmenopausal women.

The aim of this study was to histologically and biochemically analyze the effects of light-emitting diode therapy (LEDT) associated with resistance training to prevent sarcopenia in ovariectomized rats. Forty female Wistar rats (12 months old, 295-330 g) were bilaterally ovariectomized and divided into four groups (n = 10 per group): control-sedentary (C), resistance training (T), LEDT-sedentary (L), and LEDT plus resistance training (LT). Trained rats performed a 12-week water-jumping program (3 days per week) carrying a load equivalent to 50-80% of their body mass strapped to their back. Depending on the group protocol, the LED device (850 nm, 100 mW, 120 J/cm(2), spot size 0.5 cm(2)) was used either as the only method or after the resistance training had been performed. The device was used in the single point contact mode (for 10 min). The irradiated region was the center of the greater trochanter of the right femur and the middle third of the rectus femoris muscle was subsequently analyzed histomorphometrically. Significant increases (p < 0.05) were noted for the muscle volume of the T (68.1 ± 19.7%), the L (74.1 ± 5.1%), and the LT (68.2 ± 11.5%) groups compared to the C group (60.4 ± 5.5%). There were also significant increases in the concentrations of IGF-1, IL-1, and TNF-α in the muscles of the treated groups (p < 0.05). Animals in the LT group showed a significant increase in IL-6 compared to T, L, and C groups (p < 0.05). These findings suggest that resistance training and LEDT can prevent sarcopenia in ovariectomized rats.

Emitting Diodes -(LEDs) são uma fonte de luz que estão sendo introduzidas comercialmente, mas com discreta base científica nesta modalidade fototerapêutica. O presente estudo comparou os efeitos angiogênicos da luz Laser coerente e colimada à luz LED ausente de coerência e colimação em feridas induzidas em ratos, com fluências diferentes. O modelo experimental consistia da indução de uma ferida circular no quadríceps de 120 ratos, utilizando um "punch" com 15 mm de diâmetro. Os animais foram divididos aleatoriamente em 5 grupos: Laser (660 nm) e LED (635 nm), sendo cada um ajustado a 5 J/cm 2 e 20 J/cm 2 , além do Controle. Após 6 horas da indução das feridas, os grupos tratados recebiam aplicação pontual de contato, e irradiados a cada 24 horas. A angiogênese foi analisada por meio da histomorfometria (H.E), e a contração das feridas pelo Software de Planimetria, sendo estudados os resultados no 3º, 7º, 14º e 21º dias pós-lesão. Os achados da análise histológica no 3º dia foram determinantes para induzir uma grande eficiência na proliferação de vasos sanguíneos dos grupos tratados em relação ao controle, demonstrando uma taxa próxima da constante no 7º dia, e com discreto aumento no 14º dia, porém com destaque para a tecnologia LED a 5 J/cm 2 (p≤0,05). No 21º dia, os grupos fototratados com fluência de 5 J/cm² apresentavam valores estatísticos com maior eficiência na angiogênese quando comparados com o grupo Laser a 20 J/cm², sugerindo que fluências elevadas podem induzir um processo do tipo saturação. Não ocorreu diferença da neovascularização no centro e nas margens da ferida (p≤0,05), sugerindo que ocorria uma fotobiomodulação de toda a lesão, favorecendo o crescimento homogêneo dos vasos sanguíneos. Tanto o Laser quanto o LED não apresentaram resultados significativos na redução da área das feridas. As fototerapias a Laser e LED de baixa intensidade sugeriram que a coerência e a colimação não eram fatores decisivos para induzir alterações nas funções celulares, e sim a banda de absorção do espectro eletromagnético. Ambas as fonte de luz vermelha ajustadas a fluências de 5 J/cm² podem demonstrar resultados expressivos no estímulo angiogênico em pele lesada.Palavras-chave: angiogênese, contração de feridas, cicatrização, Diodos Emissores de Luz (LEDs), Laserterapia de Baixa Intensidade (LLLT), histomorfometria. ABSTRACT CORAZZA, A. V. (2005). Comparative fotobiomodulation between the LED and lowintensity laser in the angiogenisis of skin wounds in rats.The Light Emitting Diodes (LEDs) are a source of light that have been commercially introduced, but still with a lack in its scientific basis in this phototherapeutic modality. The present study compared the angiogenics effects of the laser and LED illumination in induced wounds in rat, with fluencies different. The experimental model consisted of the induction of a circular wound on the quadriceps of 120 rats, using a "punch" with 15 mm diameter. Animals were divided randomyzed in 5 groups: Laser and LED each device with a dosage of 5 J/cm² and 20 J/cm², and Con...