Source-Specific Photobiomodulation Regulates Mitochondrial Bioenergetics, Redox Signaling, and Functional Outputs in...

Area of Science:

• Cell Biology
• Mitochondrial Function
• Aging Research

Background:

• Age-related muscle decline involves mitochondrial dysfunction and reduced myogenic capacity.
• The specific effects of different photobiomodulation (PBM) delivery sources on aging cells are not well understood.

Purpose of the Study:

• To investigate how different PBM sources (660 nm LED vs. 830 nm NIR laser) affect cellular processes in replicatively aged C2C12 myoblasts.
• To determine optimal PBM fluence and analyze source-specific responses in young and aged cells.

Main Methods:

• Utilized C2C12 myoblasts at different passage numbers (young: ≤5, old: ≥30).
• Employed single-cell screening to identify optimal fluence (5 J/cm²) for both 660 nm LED and 830 nm NIR laser.
• Conducted population-level assays to assess mitochondrial membrane potential, ROS levels, ATP production, myogenic fusion, and extracellular vesicle release.

Main Results:

• Optimal PBM fluence of 5 J/cm² induced biphasic increases in mitochondrial membrane potential and ROS for both sources.
• LED irradiation enhanced metabolic activation and ATP production, especially in aged cells.
• NIR irradiation significantly improved myogenic fusion in both young and aged cells, partially rescuing differentiation deficits in aged cells.
• Extracellular vesicle release showed age-dependent, source-specific patterns, with NIR favoring young cells and LED favoring aged cells.

Conclusions:

• PBM utilizes conserved mitochondrial signaling pathways.
• Wavelength and delivery source-specific PBM differentially influence metabolic, paracrine, and myogenic outcomes in aging muscle cells.
• These findings highlight the potential for tailored PBM strategies to address age-related muscle decline.