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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.

Giacci MK, Wheeler L, Lovett S, Dishington E, Majda B, Bartlett CA, Thornton E, Harford-Wright E, Leonard A, Vink R, Harvey AR, Provis J, Dunlop SA, Hart NS, Hodgetts S, Natoli R, Van Den Heuvel C, Fitzgerald M - PLoS ONE (2014)

Bottom Line: 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.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).

View Article: PubMed Central - PubMed

Affiliation: 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.

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.

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Penetrance of light through rat skin and muscle and irradiance delivered by the 670/NIR-IT LED arrays.(A) Spectral transmittance of light from 300 nm to 890 nm through skin (red), muscle (green), and skin plus muscle combined (blue), taken from the area overlying the SCI injury site in a Fischer rat cadaver (n = 1). Spectral irradiance (300–890 nm) received at the surface of the skin from the 670 nm (B) or 830 nm (C) LED arrays at a distance of 3 cm (blue lines) and calculated numbers of photons reaching the SCI injury site (red line).
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pone-0104565-g001: Penetrance of light through rat skin and muscle and irradiance delivered by the 670/NIR-IT LED arrays.(A) Spectral transmittance of light from 300 nm to 890 nm through skin (red), muscle (green), and skin plus muscle combined (blue), taken from the area overlying the SCI injury site in a Fischer rat cadaver (n = 1). Spectral irradiance (300–890 nm) received at the surface of the skin from the 670 nm (B) or 830 nm (C) LED arrays at a distance of 3 cm (blue lines) and calculated numbers of photons reaching the SCI injury site (red line).

Mentions: The effect of wavelength of light on penetrance of R/NIR light through skin and/or muscle was assessed by measuring the spectral transmittance (300 nm to 890 nm) of the tissue overlying the spinal cord in a Fischer rat cadaver, allowing calculation of the irradiation doses received at the injury site in the SCI model. Transmittance was higher through skin than muscle, and was greatest between 750–890 nm, with a minor secondary peak at around 500 nm (Fig. 1A). Unlike lasers, LEDS are not monochromatic and instead are narrowband light sources that emit significant amounts of light either side of the specified emission peak (Fig. 1A, B). Thus, measured irradiances produced by the LED devices are integrated over the wavelength range 400–890 nm. The total irradiance of R/NIR-IT received at the surface of the skin, 3 cm from the emission surface of the 670 nm device, was 5.3×1016 photons cm−2 s−1 (peak irradiance at 670 nm was approximately 2×1015 photons cm−2 s−1) and this was calculated to drop to 3.5×1015 photons cm−2 s−1 (6.6%) at the SCI injury site, below the overlying skin and muscle (Fig. 1B). Similarly, the total irradiance of R/NIR-IT received at the surface of the skin, 3 cm from the surface of the 830 nm device, was 5.3×1016 photons cm−2 s−1 (peak irradiance at 830 nm was approximately 1.2×1015 photons cm−2 s−1) and this dropped to 6.0×1015 photons cm−2 s−1 (11.3%) at the SCI injury site (Fig. 1C).


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.

Giacci MK, Wheeler L, Lovett S, Dishington E, Majda B, Bartlett CA, Thornton E, Harford-Wright E, Leonard A, Vink R, Harvey AR, Provis J, Dunlop SA, Hart NS, Hodgetts S, Natoli R, Van Den Heuvel C, Fitzgerald M - PLoS ONE (2014)

Penetrance of light through rat skin and muscle and irradiance delivered by the 670/NIR-IT LED arrays.(A) Spectral transmittance of light from 300 nm to 890 nm through skin (red), muscle (green), and skin plus muscle combined (blue), taken from the area overlying the SCI injury site in a Fischer rat cadaver (n = 1). Spectral irradiance (300–890 nm) received at the surface of the skin from the 670 nm (B) or 830 nm (C) LED arrays at a distance of 3 cm (blue lines) and calculated numbers of photons reaching the SCI injury site (red line).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126771&req=5

pone-0104565-g001: Penetrance of light through rat skin and muscle and irradiance delivered by the 670/NIR-IT LED arrays.(A) Spectral transmittance of light from 300 nm to 890 nm through skin (red), muscle (green), and skin plus muscle combined (blue), taken from the area overlying the SCI injury site in a Fischer rat cadaver (n = 1). Spectral irradiance (300–890 nm) received at the surface of the skin from the 670 nm (B) or 830 nm (C) LED arrays at a distance of 3 cm (blue lines) and calculated numbers of photons reaching the SCI injury site (red line).
Mentions: The effect of wavelength of light on penetrance of R/NIR light through skin and/or muscle was assessed by measuring the spectral transmittance (300 nm to 890 nm) of the tissue overlying the spinal cord in a Fischer rat cadaver, allowing calculation of the irradiation doses received at the injury site in the SCI model. Transmittance was higher through skin than muscle, and was greatest between 750–890 nm, with a minor secondary peak at around 500 nm (Fig. 1A). Unlike lasers, LEDS are not monochromatic and instead are narrowband light sources that emit significant amounts of light either side of the specified emission peak (Fig. 1A, B). Thus, measured irradiances produced by the LED devices are integrated over the wavelength range 400–890 nm. The total irradiance of R/NIR-IT received at the surface of the skin, 3 cm from the emission surface of the 670 nm device, was 5.3×1016 photons cm−2 s−1 (peak irradiance at 670 nm was approximately 2×1015 photons cm−2 s−1) and this was calculated to drop to 3.5×1015 photons cm−2 s−1 (6.6%) at the SCI injury site, below the overlying skin and muscle (Fig. 1B). Similarly, the total irradiance of R/NIR-IT received at the surface of the skin, 3 cm from the surface of the 830 nm device, was 5.3×1016 photons cm−2 s−1 (peak irradiance at 830 nm was approximately 1.2×1015 photons cm−2 s−1) and this dropped to 6.0×1015 photons cm−2 s−1 (11.3%) at the SCI injury site (Fig. 1C).

Bottom Line: 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.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).

View Article: PubMed Central - PubMed

Affiliation: 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.

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.

Show MeSH
Related in: MedlinePlus