Open Access Highly Accessed Research article

Low infra red laser light irradiation on cultured neural cells: effects on mitochondria and cell viability after oxidative stress

Alessandro Giuliani1*, Luca Lorenzini1, Michele Gallamini2, Alessandro Massella1, Luciana Giardino13 and Laura Calzà13

Author Affiliations

1 BioPharmaNet-DIMORFIPA, University of Bologna, Via Tolara di Sopra 50, 40064 Ozzano dell'Emilia, Bologna, Italy

2 RGMD-Medical Devices Division, Via Rolla 13/13 16152 Genova, Italy

3 National Institute of Biostructures and Biosystems (INBB), Viale medaglie d'Oro 305 – 00136 Roma, Italy

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BMC Complementary and Alternative Medicine 2009, 9:8  doi:10.1186/1472-6882-9-8

Published: 15 April 2009



Considerable interest has been aroused in recent years by the well-known notion that biological systems are sensitive to visible light. With clinical applications of visible radiation in the far-red to near-infrared region of the spectrum in mind, we explored the effect of coherent red light irradiation with extremely low energy transfer on a neural cell line derived from rat pheochromocytoma. We focused on the effect of pulsed light laser irradiation vis-à-vis two distinct biological effects: neurite elongation under NGF stimulus on laminin-collagen substrate and cell viability during oxidative stress.


We used a 670 nm laser, with extremely low peak power output (3 mW/cm2) and at an extremely low dose (0.45 mJ/cm2). Neurite elongation was measured over three days in culture. The effect of coherent red light irradiation on cell reaction to oxidative stress was evaluated through live-recording of mitochondria membrane potential (MMP) using JC1 vital dye and laser-confocal microscopy, in the absence (photo bleaching) and in the presence (oxidative stress) of H2O2, and by means of the MTT cell viability assay.


We found that laser irradiation stimulates NGF-induced neurite elongation on a laminin-collagen coated substrate and protects PC12 cells against oxidative stress.


These data suggest that red light radiation protects the viability of cell culture in case of oxidative stress, as indicated by MMP measurement and MTT assay. It also stimulates neurite outgrowth, and this effect could also have positive implications for axonal protection.