Photobiomodulation enhancement of cell proliferation at 660 nm does not require cytochrome c oxidase

Publication date: Available online 22 March 2019Source: Journal of Photochemistry and Photobiology B: BiologyAuthor(s): Paula L.V. Lima, Claudia V. Pereira, Nadee Nissanka, Tania Arguello, Giulio Gavini, Carlos Magno da Costa Maranduba, Francisca Diaz, Carlos T. MoraesAbstractPhotobiomodulation (PBM) therapy is based on the use of specific light parameters to promote tissue repair. Although demonstrated in different cell models and tissues, the mechanism by which photobiomodulation operates is not well understood. Previous studies suggested that the cell proliferation enhancement triggered by red and near-infrared PBM involves the activation of the mitochondrial respiratory chain enzyme cytochrome c oxidase (CCO). It was suggested that light in this range would displace inhibitory nitric oxide bound to CCO. To test this mechanism, we took advantage of cell lines lacking CCO, including a mouse line knockout for Cox10 (a gene required for the synthesis of heme a, the prosthetic group of CCO) and a human cell line with an mtDNA mutation in the tRNA Lysine gene, leading to mitochondrial protein synthesis impairment and the lack of three critical CCO subunits. In both models we showed the complete absence of assembled CCO. PBM (660 nm) was applied to these proliferating cells using various parameters. In most of the conditions tested, increased cell proliferation was associated with PBM in both control and CCO negative cells, demonstrating that CCO is not required for PBM enhanc...
Source: Journal of Photochemistry and Photobiology B: Biology - Category: Speech-Language Pathology Source Type: research