Photobiomodulation by 670nm light protects against oxidative stress in multiple organs in a rodent model of diabetes mellitus

Abstract

Purpose: Photobiomodulation (PBM) by light in the far-red to near-infrared range of the spectrum has been shown to have therapeutic benefit in experimental and clinical disease. We have demonstrated the usefulness of PBM on early lesions in diabetic retinopathy. This study evaluates the effects of PBM on heart, kidney, peripheral nerves and bone marrow in diabetes.

Methods: Methods: Animals were assigned to 3 groups, nondiabetic controls and diabetic animals with or without PBM treatment (25 mW/cm2, 200-300 secs, 5-7.5 J/cm2). Animals were handled in accordance with the Guide for the Care and Use of Laboratory Animals as adopted and promulgated by the National Institutes of Health. All experimental procedures were reviewed and approved by the Case Western Reserve University and University of Wisconsin-Milwaukee Institutional Animal Care and Use Committee.

Results: Diabetic rats exhibited increased oxidative stress and dysfunction in retina, kidney, bone marrow and heart. PBM therapy significantly improved these parameters. In the retina and bone marrow, PBM significantly inhibited the diabetes-induced production of superoxide and normalized MnSOD expression in-vivo. In the heart PBM protected against total antioxidant loss and diabetes-induced reduction of catalase and thioredoxin activity in the heart. In the kidney, PBM improved kidney function, and increased catalase and Na K-ATPase activity. Allodynia was also attenuated following PBM treatment.

Conclusions: PBM offers a brief and noninvasive method to inhibit the development of retinal dysfunction and several biochemical changes characteristic of diabetes in different organ systems.

Keywords: 499 diabetic retinopathy • 695 retinal degenerations: cell biology • 634 oxidation/oxidative or free radical damage