Low level laser (light) therapy has been used before exercise to increase muscle performance in both experimental animals and in humans. However uncertainty exists concerning the optimum time to apply the light before exercise. The mechanism of action is thought to be stimulation of mitochondrial respiration in muscles, and to increase adenosine triphosphate (ATP) needed to perform exercise. The goal of this study was to investigate the time course of the increases in mitochondrial membrane potential (MMP) and ATP in myotubes formed from C2C12 mouse muscle cells and exposed to light-emitting diode therapy (LEDT). LEDT employed a cluster of LEDs with 20 red (630 ± 10 nm, 25 mW) and 20 near-infrared (850 ± 10 nm, 50 mW) delivering 28 mW/cm2 for 90 sec (2.5 J/cm2) with analysis at 5 min, 3 h, 6 h and 24 h post-LEDT. LEDT-6h had the highest MMP, followed by LEDT-3h, LEDT-24h, LEDT-5min and Control with significant differences. The same order (6h>3h>24h>5min>Control) was found for ATP with significant differences. A good correlation was found (r=0.89) between MMP and ATP. These data suggest an optimum time window of 3-6 h for LEDT stimulate muscle cells.

Light-emitting diode therapy (LEDT) applied over the leg, gluteus and lower-back muscles of mice using a LED cluster (630 nm and 850 nm, 80 mW/cm2, 7.2 J/cm2) increased muscle performance (repetitive climbing of a ladder carrying a water-filled tube attached to the tail), ATP and mitochondrial metabolism; oxidative stress and proliferative myocyte markers in mice subjected to acute and progressive strength training. Six bi-daily training sessions LEDT-After and LEDT-Before-After regimens more than doubled muscle performance and increased ATP more than tenfold. The effectiveness of LEDT on improving muscle performance and recovery suggest applicability for high performance sports and in training programs. Positioning of the mice and light-emitting diode therapy (LEDT) applied on mouse legs, gluteus and lower-back muscles without contact.

Photobiomodulation (PBM) is a simple, efficient and cost-effective treatment for both acute and chronic pain. We previously showed that PBM applied to the mouse head inhibited nociception in the foot. Nevertheless, the optimum parameters, location for irradiation, duration of the effect and the mechanisms of action remain unclear. In the present study, the pain threshold in the right hind paw of mice was studied, after PBM (810 nm CW laser, spot size 1 or 6 cm , 1.2-36 J/cm ) applied to various anatomical locations. The pain threshold, measured with von Frey filaments, was increased more than 3-fold by PBM to the lower back (dorsal root ganglion, DRG), as well as to other neural structures along the pathway such as the head, neck and ipsilateral (right) paw. On the other hand, application of PBM to the contralateral (left) paw, abdomen and tail had no effect. The optimal effect occurred 2 to 3 hours post-PBM and disappeared by 24 hours. Seven daily irradiations showed no development of tolerance. Type 1 metabotropic glutamate receptors decreased, and prostatic acid phosphatase and tubulin-positive varicosities were increased as shown by immunofluorescence of DRG samples. These findings elucidate the mechanisms of PBM for pain and provide insights for clinical practice.

Abstract. Photobiomodulation or low-level light therapy has been shown to attenuate both acute and chronic pain, but the mechanism of action is not well understood. In most cases, the light is applied to the painful area, but in the present study we applied light to the head. We found that transcranial laser therapy (TLT) applied to mouse head with specific parameters (810 nm laser, 300 mW∕cm 2 , 7.2 or 36 J∕cm 2 ) decreased the reaction to pain in the foot evoked either by pressure (von Frey filaments), cold, or inflammation (formalin injection) or in the tail (evoked by heat). The pain threshold increasing is maximum around 2 h after TLT, remains up to 6 h, and is finished 24 h after TLT. The mechanisms were investigated by quantification of adenosine triphosphate (ATP), immunofluorescence, and hematoxylin and eosin (H&E) staining of brain tissues. TLT increased ATP and prostatic acid phosphatase (an endogenous analgesic) and reduced the amount of glutamate receptor (mediating a neurotransmitter responsible for conducting nociceptive information). There was no change in the concentration of tubulin, a constituent of the cytoskeleton, and the H&E staining revealed no tissue damage.

Light-emitting diode therapy (LEDT) applied over the leg, gluteus and lower-back muscles of mice using a LED cluster (630 nm and 850 nm, 80 mW/cm2, 7.2 J/cm2) increased muscle performance (repetitive climbing of a ladder carrying a water-filled tube attached to the tail), ATP and mitochondrial metabolism; oxidative stress and proliferative myocyte markers in mice subjected to acute and progressive strength training. Six bi-daily training sessions LEDT-After and LEDT-Before-After regimens more than doubled muscle performance and increased ATP more than tenfold. The effectiveness of LEDT on improving muscle performance and recovery suggest applicability for high performance sports and in training programs.

Resumen La seguridad ha sido un tema muy discutido, por lo que muestra su relevancia para la salud pública y los proyectos de investigación que involucran a seres humanos. Los participantes en estudios clínicos están sujetos a riesgos físicos o de otro tipo, que impactarán su integridad, derechos o autonomía. Este texto realiza un debate sobre el desempeño del Comité de Seguimiento de Datos y Seguridad destinado a la protección de los participantes de investigación y la mitigación de los riesgos en investigación clínica. Se realizó una revisión integradora de la literatura, con el propósito de identificar las funciones de los comités y su rol en la protección de los participantes. La mayoría de las publicaciones analizadas confirman que los comités de seguimiento tienen como principal responsabilidad la protección del participante de la investigación, además de garantizar la integridad y credibilidad de la investigación.

Of increasingly relevance in public health and research projects involving human beings, the topic of safety has been intensely discussed. Participants in clinical trials are subject to risks, physical or otherwise, that impact their integrity, rights, or autonomy. This study outlines and discusses the performance of the Data and Safety Monitoring Committee for research participant protection and risk minimization in clinical research. An integrative literature review was conducted to identify the committees’ duties and role in protecting participants. Most of the analyzed articles confirm that the monitoring committees are mainly responsible for protecting research participants, as well as ensuring research integrity and credibility.

Resumo O tema segurança tem sido intensamente discutido, mostrando-se cada vez mais relevante na saúde pública e em projetos de pesquisa envolvendo seres humanos. Participantes de estudos clínicos estão sujeitos a riscos, físicos ou não, que impactam em sua integridade, direitos ou autonomia. Este trabalho apresenta e discute a atuação do Comitê de Monitoramento de Dados e de Segurança para a proteção do participante de pesquisa e minimização de riscos em pesquisa clínica. A metodologia consiste em revisão integrativa da literatura, realizada com o propósito de identificar as funções dos comitês e seu papel na proteção dos participantes. Identificou-se que grande parte das publicações analisadas confirmam que os comitês de monitoramento têm como responsabilidade principal a proteção do participante de pesquisa, além da garantia de integridade e credibilidade da pesquisa.