1 Biomedical Sciences, Univ of Wisconsin - Milwaukee, Milwaukee, WI
2 Physiology, Medical College of Wisconsin, Milwaukee, WI
3 Ophthalmology, Medical College of Wisconsin, Milwaukee, WI
4 Electrical Engineering and Computer Science, University of Wisconsin-Milwaukee, Milwaukee, WI
5 Ophthalmology, Duke University, Durham, NC
6 Ophthalmology, University of Wisconsin, Madison, WI
Commercial Relationships: Janis Eells, QBMI Photomedicine (C); Sandeep Gopalakrishnan, None; Mahsa Ranji, None; Sepideh Maleki, None; Betsy Abroe, None; Heather Schmitt, None; Adam Dubis, None; Phyllis Summerfelt, None; Joseph Carroll, Imagine Eyes, Inc. (S)
Purpose:Photobiomodulaton (PBM) by light in the far-red to near-infrared (NIR) region of the spectrum has been demonstrated to attenuate the severity of neurodegenerative disease in experimental and clinical studies. The purpose of this study was to test the hypothesis that a brief course of 830 nm PBM would protect against the loss of retinal function and improve photoreceptor survival in a rodent model of retinitis pigmentosa, the P23H transgenic rat.
Methods:All studies were conducted in compliance with the ARVO Statement for the Use of Animals in Ophthalmic and Visual Research. P23H pups were treated once per day with 830 nm light (180 s; 25 mW/cm2; 4.5 J/cm2) using a light-emitting diode array (QBMI Photomedicine, Barneveld WI) from postnatal day (p) 10 to p25. Sham-treated rats were restrained for 180 seconds, but not exposed to NIR light. The status of the retina was determined at p30 by measuring photoreceptor function by electroretinography (ERG), retinal morphology by spectral domain optical coherence tomography (SD-OCT) and retinal metabolic state by NADH/FAD redox imaging.
Results:NIR treatment preserved retinal function, retinal morphology and retinal metabolic state in NIR-treated animals in comparison to the sham-treated group. Rod and cone-mediated ERG responses over a range of flash intensities (from 10 mcd.s/m2 to 25000 cd.s/m2) were 50% greater at each light intensity in NIR-treated rats compared to sham controls. SD-OCT studies showed that NIR treatment preserved the structural integrity of the retina. Mitochondrial redox imaging studies showed that NIR treatment (1.02 ± 0.2) protected the retina against the shift towards a more oxidized state as measured by the retinal redox ratio (NADH RR) in the sham treatment (0.80 ± 0.1).
Conclusions:Results from this study demonstrate the retinoprotective effects of 830nm PBM in a widely studied animal model of retinal degeneration and support the use of PBM as an innovative, non-invasive therapeutic approach for the treatment of retinal degenerative disease.
Keywords: 696 retinal degenerations: hereditary 615 neuroprotection 648 photoreceptors
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