Differential responses of myoblasts and myotubes to photobiomodulation are associated with mitochondrial number. Issue 6 (20th February 2019)

• Record Type: Journal Article
• Authors: Serrage, Hannah J.; Joanisse, Sophie; Cooper, Paul R.; Palin, William; Hadis, Mohammed; Darch, Owen; Philp, Andrew; Milward, Mike R.
• Is Part Of: Journal of biophotonics. Volume 12:Issue 6(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-02-20
• Subjects: low‐level laser therapy -- low‐level light therapy -- mitochondria -- myogenesis -- photobiomodulation; Photonics -- Periodicals; Optical materials -- Periodicals; Optics -- Periodicals; Medical instruments and apparatus -- Periodicals; 621.3605
• DOI: 10.1002/jbio.201800411
• Languages: English
• ISSNs: 1864-063X

Abstract

Abstract : Objective: Photobiomodulation (PBM) is the application of light to promote tissue healing. Current indications suggest PBM induces its beneficial effects in vivo through upregulation of mitochondrial activity. However, how mitochondrial content influences such PBM responses have yet to be evaluated. Hence, the current study assessed the biological response of cells to PBM with varying mitochondrial contents. Methods: DNA was isolated from myoblasts and myotubes (differentiated myoblasts), and mitochondrial DNA (mtDNA) was amplified and quantified using a microplate assay. Cells were seeded in 96‐wellplates, incubated overnight and subsequently irradiated using a light‐emitting diode array (400, 450, 525, 660, 740, 810, 830 and white light, 24 mW/cm 2, 30‐240 seconds, 0.72‐5.76J/cm 2 ). The effects of PBM on markers of mitochondrial activity including reactive‐oxygen‐species and real‐time mitochondrial respiration (Seahorse XFe96) assays were assessed 8 hours post‐irradiation. Datasets were analysed using general linear model followed by one‐way analysis of variance (and post hoc‐Tukey tests); P = 0.05). Results: Myotubes exhibited mtDNA levels 86% greater than myoblasts ( P < 0.001). Irradiation of myotubes at 400, 450 or 810 nm induced 53%, 29% and 47% increases (relative to non‐irradiated control) in maximal respiratory rates, respectively ( P < 0.001). Conversely, irradiation of myoblasts at 400 or 450 nm had no significant effect on maximal respiratory rates. Conclusion: This study suggests that mitochondrial content may influence cellular responses to PBM and as such explain the variability of PBM responses seen in the literature. Abstract : We demonstrate novel findings that suggest the effects of photobiomodulation (PBM) are mitochondrial content dependent. In which muscle cells with different mitochondrial contents were evaluated for their response to PBM. It was found that cells possessing a higher mitochondrial content (myotubes) exhibited a greater real‐time mitochondrial response to, in particular, blue light (400‐450 nm).