Morpho-functional evaluation of the effects of red photobiomodulation on skeletal myoblasts undergoing differentiation.

Adult skeletal muscle possesses the ability to regenerate lost damaged tissue mainly thanks to the activity of a small population of resident stem cells, called satellite cells (SCs). In the case of chronic or severe damage SCs functionality may be compromised by the occurrence of an aberrant fibrotic reparative response. Strategies aimed to improve the muscle intrinsic regenerative potential while limiting the excessive deposition of fibrotic tissue may be promising. In this perspective, Photobiomodulation (PBM) ( i. e. application of light with 400 1100 nm wavelength using different laser or LED devices , power density less than 100 mW/c m 2 and energy density less than 10 J/ c m 2 at target) may represent a valid option based on its well known pro regenerative effects and increasing evidence of its antifibrotic potential. However, results on the PBM actual benefits on skeletal muscle are controversial and light tissue interactions need to be better elucidated. This research aimed to evaluate the effects of a treatment of red PBM (635±5 nm, energy density: 0.4, 4 and 8 J/ c m 2 single exposure) on myoblastic cells (murine C2C12 and human skeletal myoblasts) undergoing differentiation. Preliminary results obtained by morphological analyses (viabilit y, proliferation, myogenic markers, myotubes, mitochondria biogenesis) and electrophysiological investigations (cell membrane passive properties and ion currents) suggest the capability of red PBM to positively affect cell differentiation. Experiments are ongoing to explore the effects of red PBM on myoblasts induced to differentiate on a liquid crystalline network as a cell instructive scaffold to support a correct myogenic differentiation.