Effects of photobiomodulation therapy on functional recovery, angiogenesis and redox status in denervated muscle of rats

Objective:  To evaluate the effects of photobiomodulation therapy in redox status, angiogenesis marker – vascular endothelial growth factor – and in the functional recovery in denervated muscle.

Methods:  A total of 32 female Wistar rats underwent a crush injury and were randomly divided into four groups: Light Emitting Diode Group 2 and Control Group 2 (muscle collected 2 days after injury), and Light Emitting Diode Group 21 and Control Group 21 (muscle collected 21 days afterinjury). Light Emitting Diode Group 2 and Light Emitting Diode Group 21 received two and ten light emitting diode applications (630±20nm, 9J/cm², 300mW), respectively, and the Control Group 2 and Control Group 21 did not receive any treatment. The function was evaluated by grasping test at four moments (pre-injury, 2, 10 and 21 post-injury days). The flexor digitorum muscle was collected for analysis of immunolocalization of vascular endothelial growth factor and redox parameters.

Results:  Functional improvement was observed at the second and tenth post-injury day in treated groups compared to control (p<0.005). The muscle tissue of treated groups presented higher immunohistochemical expression of vascular endothelial growth factor. Photobiomodulation therapy decreased the oxidative damage to lipid in Light Emitting Diode Group 2 compared to Control Group 2 (p=0.023) in the denervated muscle.

Conclusion:  Photobiomodulation therapy accelerated the functional recovery, increased angiogenesis and reduced lipid peroxidation in the denervated muscle at 2 days after injury.

Keywords:
Muscles; Crush injuries; Phototherapy; Oxidative stress; Vascular endothelial growth factors; Muscle strength; Rats, Wistar