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PLoS One. 2014 Aug 8;9(8):e104565. doi: 10.1371/journal.pone.0104565. eCollection 2014.

Differential effects of 670 and 830 nm red near infrared irradiation therapy: a comparative study of optic nerve injury, retinal degeneration, traumatic brain and spinal cord injury.

Author information

1
Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Australia; School of Animal Biology, The University of Western Australia, Crawley, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Australia.
2
Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Australia.
3
Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Australia; School of Animal Biology, The University of Western Australia, Crawley, Australia.
4
School of Medical Sciences, The University of Adelaide, Adelaide, Australia.
5
ANU Medical School and John Curtin School of Medical Research, The Australian National University, Canberra, Australia.
6
School of Animal Biology, The University of Western Australia, Crawley, Australia; Neuroecology Group, The Oceans Institute, The University of Western Australia, Crawley, Australia.

Abstract

Red/near-infrared irradiation therapy (R/NIR-IT) delivered by laser or light-emitting diode (LED) has improved functional outcomes in a range of CNS injuries. However, translation of R/NIR-IT to the clinic for treatment of neurotrauma has been hampered by lack of comparative information regarding the degree of penetration of the delivered irradiation to the injury site and the optimal treatment parameters for different CNS injuries. We compared the treatment efficacy of R/NIR-IT at 670 nm and 830 nm, provided by narrow-band LED arrays adjusted to produce equal irradiance, in four in vivo rat models of CNS injury: partial optic nerve transection, light-induced retinal degeneration, traumatic brain injury (TBI) and spinal cord injury (SCI). The number of photons of 670 nm or 830 nm light reaching the SCI injury site was 6.6% and 11.3% of emitted light respectively. Treatment of rats with 670 nm R/NIR-IT following partial optic nerve transection significantly increased the number of visual responses at 7 days after injury (P ≤ 0.05); 830 nm R/NIR-IT was partially effective. 670 nm R/NIR-IT also significantly reduced reactive species and both 670 nm and 830 nm R/NIR-IT reduced hydroxynonenal immunoreactivity (P ≤ 0.05) in this model. Pre-treatment of light-induced retinal degeneration with 670 nm R/NIR-IT significantly reduced the number of Tunel+ cells and 8-hydroxyguanosine immunoreactivity (P ≤ 0.05); outcomes in 830 nm R/NIR-IT treated animals were not significantly different to controls. Treatment of fluid-percussion TBI with 670 nm or 830 nm R/NIR-IT did not result in improvements in motor or sensory function or lesion size at 7 days (P>0.05). Similarly, treatment of contusive SCI with 670 nm or 830 nm R/NIR-IT did not result in significant improvements in functional recovery or reduced cyst size at 28 days (P>0.05). Outcomes from this comparative study indicate that it will be necessary to optimise delivery devices, wavelength, intensity and duration of R/NIR-IT individually for different CNS injury types.

PMID:
25105800
PMCID:
PMC4126771
DOI:
10.1371/journal.pone.0104565
[Indexed for MEDLINE]
Free PMC Article
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