Comparative assessment of phototherapy protocols for reduction of oxidative stress in partially transected spinal cord slices undergoing secondary degeneration

Abstract

BackgroundRed/near-infrared light therapy (R/NIR-LT) has been developed as a treatment for a range of conditions, including injury to the central nervous system (CNS). However, clinical trials have reported variable or sub-optimal outcomes, possibly because there are few optimized treatment protocols for the different target tissues. Moreover, the low absolute, and wavelength dependent, transmission of light by tissues overlying the target site make accurate dosing problematic.ResultsIn order to optimize light therapy treatment parameters, we adapted a mouse spinal cord organotypic culture model to the rat, and characterized myelination and oxidative stress following a partial transection injury. The ex vivo model allows a more accurate assessment of the relative effect of different illumination wavelengths (adjusted for equal quantal intensity) on the target tissue. Using this model, we assessed oxidative stress following treatment with four different wavelengths of light: 450 nm (blue); 510 nm (green); 660 nm (red) or 860 nm (infrared) at three different intensities: 1.93 × 1016 (low); 3.85 × 1016 (intermediate) and 7.70 × 1016 (high) photons/cm2/s. We demonstrate that the most effective of the tested wavelengths to reduce immunoreactivity of the oxidative stress indicator 3-nitrotyrosine (3NT) was 660 nm. 860 nm also provided beneficial effects at all tested intensities, significantly reducing oxidative stress levels relative to control (p ≤ 0.05).ConclusionsOur results indicate that R/NIR-LT is an effective antioxidant therapy, and indicate that effective wavelengths and ranges of intensities of treatment can be adapted for a variety of CNS injuries and conditions, depending upon the transmission properties of the tissue to be treated.

Under the spotlight: mechanisms of photobiomodulation concentrating on blue and green light

“…A second Scopus database search was undertaken to evaluate the effects of green light PBM using the terms described in Figure 3b. An initial search resulted in 236 articles being identified and these articles were subsequently screened for suitability, which then identified 32 relevant articles for further review (18,32,33,64,68,69,79,164,168,171,176,177,186,197,205,209,(212)(213)(214)(215)(216)(217)(218)(219)(220)(221)(222)(223)(224)(225)(226)(227).…”

Red Light Irradiation In Vivo Upregulates DJ-1 in the Retinal Ganglion Cell Layer and Protects against Axotomy-Related Dendritic Pruning

“…There was no effect of light treatment on 3-NT levels in the GCL of mutant mice. Red light PBM has previously been associated with the alleviation of nitrosative stress in the CNS [50,51]. However, these studies did not assess light treatment in an in vivo model of chronic mitochondrial dysfunction, and so it is unsurprising that the short course of 670 nm PBM treatment did not reverse the nitrosative damage that had already occurred.…”

A clinical approach to diagnosis and management of mitochondrial myopathies

“…Uncertain effect on muscle strength, effort tolerance and quality of life. [ 61 , 61 , 107 , 108 ] Device Reduce oxidative stress Near-infrared light-emitting diode In vitro evidence as an effective antioxidant therapy [ 109 , 110 ] Modulate cortical and subcortical functional abnormalities Transcranial direct current stimulation Improved mitochondrial function and attenuated mitochondrial damage in mouse models. Aided improved clinical outcomes in autism, dyslexia and attention deficit.…”