Efeitos da terapia por fotobiomodulação nas variáveis metabólicas, hemodinâmicas e ventilatórias no diabetes mellitus tipo 2

Abstract

Study 1: Aim: to investigate, through the NIRS, the acute effects of PBMT by light emitting diode (LED) on the oxygen delivery and utilization in humans. Methods: Twelve healthy young participants were treated with a LED device (850 nm, 50 mW, 2 J) and sham applied over the proximal third of the flexor carpi ulnaris muscle of the left or right forearm selected in a random order. The LED was applied in direct contact with skin and the device was switched on for 40 s in 4 different interventions (I1, I2, I3 and I4) with a 3-minute interval between interventions. The sham condition was considered as the period before the first PBMT. The NIRS device was used to evaluate the relative changes in [O2Hb] and [HHb] before and after sham and interventions. Results: We found that PBMT statistically increased the [O2Hb] in 0.39 μM. Conclusion: These results demonstrate the potential of PBMT to increase oxygen availability. Study 2: Aim: The main purpose of this study was to verify the acute dose-response effect of PBMT by light emitting diodes (LEDs) on hemodynamic and metabolic responses in individuals with type 2 diabetes mellitus (T2DM). Methods: Thirteen participants with T2DM (age 52.6 ± 7.3 years) received PBMT by a light-emitting diode array (50 GaAIAs LEDs, 850 nm, 75 mW per diode) on the rectus and oblique abdomen, quadriceps femoris, triceps surae, and hamstrings muscle areas, bilaterally, using different energies treatments (sham, 75, 150, 300, 450 and 600 Joules - J) in random order with a wash out of at least 15 days apart. On the day of the experimental protocol, the subjects were placed at rest, to perform the first blood sample collection from the right ear lobe through a heparinized capillary, for later analysis of blood glucose and blood lactate levels. After 5 minutes of rest, PBMT (effective or sham) was applied, and a second blood sample was collected 1 minute after TFBM irradiation. Finally, 15 minutes after TFBM irradiation, the third blood collection was performed. Results: The TPBM by LEDs statistically decreased blood glucose levels in the 15 minutes after application of the 75 and 450 J irradiation protocol; reduced blood lactate levels 15 minutes after application of the 75, 450 and 600 J irradiation protocol; increased cardiac output (Q) and cardiac index (CI) in the 1st minute after application of the 75 and 300 J irradiation protocol; and reduced Q and HR in the 15 minutes after application of the 300 J and 600 J irradiation protocol, respectively. Conclusion: In conclusion, for positive modifications on hemodynamic variables, the ideal therapeutic window was the range from 75 to 300 J, whereas for the metabolic variables was from 450 to 600 J, with a power output of the 75 mW per diode LED. Study 3: Aim: The main purpose of this study was to evaluate the acute dose-response effects of TPBM associated with moderate intensity exercise, consisting of a constant load protocol (CL) followed by a binary pseudo random protocol (PRBS), in hemodynamic responses and cardiorespiratory adjustments in subjects with type 2 diabetes mellitus (T2DM). Methods: Thirteen men with T2DM (age 52.6 ± 7.3 years) received PBMT by a light-emitting diode array (50 GaAIAs LEDs, 850 nm, 75 mW per diode) on the rectus and oblique abdomen, quadriceps femoris, triceps surae, and hamstrings muscle areas, bilaterally, using different energies densities (sham, 75, 150, 300, 450 and 600 Joules - J) in random order with a washout of at least 15 days apart. After the application of TPBM, the volunteers were submitted to a CL followed by a PRBS. After the TFBM, the volunteers were submitted to an exercise protocol in cycle ergometer, consisting of a free load warm-up for 3 minutes and a CL, for a period of 6 minutes, performed at 80% of the ventilatory anaerobic threshold (VAT), achieved in a previous cardiopulmonary exercise test, and followed by a binary pseudorandom protocol (PRBS), for a time of 17 minutes and 30 seconds, with load stages that ranged from 20 to 80% of the VAT. Results: We found that TPBM enhanced the improvement of the dynamics (MNG) of Q with the energy of 600 J (p = 0.014). Conclusion: In conclusion, our findings showed that TFBM, previously applied to physical exercise, and in different energy densities, does not promote improvement in most cardiovascular and ventilatory responses. General conclusions of the study: The findings of this thesis allow us to conclude that: (1) PBMT applied in healthy young people is able to improve muscle tissue oxygenation; (2) PBMT applied in isolation, enhances the metabolic and hemodynamic responses at rest in the diabetic population, and (3) PBMT applied previously to an exercise protocol of moderate intensity and duration of 23 min, does not promotes distinct effects from the sham application in the hemodynamic variables and in the dynamics of the VO2.