Low intensity laser irradiation in myogenic precursor cells: an in vitro study (732.4)

Abstract

The aim of this study was to analyze the influence of low intensity laser irradiation at wavelengths (λ) of 670, 685 and 830 nm on the mitochondrial activity and gene expression profile of myogenic precursor cells (MPCs) in vitro. Primary rat MPCs were sown in multiwell dishes of 96 and 6 wells. Six experimental groups were set up: a non‐irradiated control group and five groups ranged by differing doses of radiation (0.3; 0.6; 0.9; 1.2 and 1.5 J/cm2). After 24 hours of irradiation, the mitochondrial activity was quantified using the colorimetric technique MTT‐formazan and established in terms of percentage in relation to the control. The gene expression profile was established through the quantitative analysis of the related isoforms IIa and IIx of the myosin heavy chain (MHC) by RT‐PCR five days after irradiation. The results showed that irradiation at λ of 670, 685 and 830 nm promoted respective increase of 56.8, 70.6 and 84.8 % on mitochondrial activity. These values were achieved with the 1.2, 0.6 and 0.3 J/cm2. As far as concerns MHC isoforms expression, this showed that there was a significant decrease in the IIa isoform (685 nm) and an increase in the IIx isoform (685 and 830 nm) in comparison to the non‐irradiated cells. Laser radiation was characterized as being a wavelength and dose‐dependent effect on the intensity of mitochondrial activity and gene expression profile among MPCs in vitro.Grant Funding Source: Supported by: Fundação de Amparo à Pesquisa do Estado se São Paulo ‐ FAPESP