Efeitos do LBP (780nm) sobre os aspectos morfológicos do complexo músculo tendíneo do músculo plantar de ratos durante o processo de hipertrofia compensatória: in vivo e in vitro

Abstract

Skeletal muscle is a tissue of great adaptive capacity and is able to change its characteristics to meet various functional demands. This adaptation can be caused by mechanical overloading which results in an increase in the size of the area of muscle fiber and increase muscle mass. This process is known as muscle hypertrophy and during numerous modifications hypertrophy occur in both the muscle tissue and tendons. Studies with low-level laser (LLL) in skeletal muscle have demonstrated that its effects are positive with respect to the reduction process of inflammation, myonecrosis and reduced influence on the collagen fibers during the remodeling process.The present study aimed to analyze the effects of LLL (780nm) during the compensatory hypertrophy process on the muscular aspects and tendon of the plantaris muscle of mice (in vivo) and also evaluate its effects on human endothelial cells (HUVECs) in vitro. They were used for the in vivo experiment 22 Wistar rats were divided into control group, non-irradiated group and irradiated group hypertrophy hypertrophy. The parameters used for the irradiation were λ = 780nm, beam area 0.04 cm2, 40mW output power, energy density of 10 J / cm2. periods of 7 and 14 days were analyzed. To cause hypertrophy model was used for ablation of synergists being taken for this study, the gastrocnemius medial and lateral muscles and the soleus muscle, leaving the plantaris muscle suffered overload. the cross-sectional area were analyzed, collagen area, the number of myonuclei and mature blood vessels in muscle tissue and the organization and arrangement of collagen fibers in the tendon. For the experiment in vitro endothelial cells were used (HUVECs) were divided into control group and the other groups irradiated also with λ = 780nm, 0.04 cm2 beam area, 40mW output power and energy density of 1 J / cm2, 5J / cm2, 10 J / cm2 to 20J / cm2. The different application time was calculated for all groups received the same dose of energy. They assessed cell viability, total protein and vessel formation in Matrigel. The in vivo results showed that there was increased cross-sectional area of the irradiated group after 14 days (26.3%) when compared to non-irradiated group. There was also increased number of myonuclei in the irradiated group after 14 days. The total area of muscle collagen increased (4.2%) in the irradiated group in 7 days and decreased (6.4%) in the irradiated group after 14 days when compared to non-irradiated group in both periods. Analysis by birefringence in the tendons showed better organization of the fibers 7 and 14 days when compared to non-irradiated group. In vitro results have shown decrease in cell viability in all irradiated all groups compared to the control and counting mature vessels was increased number of vessels in the irradiated group even after 14 days. In conclusion laser irradiation increased muscle mass, the number of myonuclei and the number of mature vessels and decreased collagen total area of muscle tissue after 14 days; improved tendon collagen organization for 7 and 14 days and interfere with the viability and total protein concentration in a dose-dependent endothelial cells HUVECs.