Photobiomodulation inhibits retinal degeneration in diabetic mice through modulation of stem cell mobilization and gene expression.

The number of people suffering from type 2 diabetes (DM2) is increasing and over 30 percent of DM2 patients will develop diabetic retinopathy (DR). Available therapeutic approaches for DR have their limitations. It is of great significance to search for other effective alternate therapeutic approaches. The present study aimed to explore the beneficial effects of photobiomodulation (PBM) on the diabetic retinopathy and underlying mechanisms. Streptozotocin was administered to male mice to establish diabetic model. The mice in the diabetic group (DM) received no treatment, and the mice in DM + PBM group received LED illumination (wavelength 670 nm) once a day for 20 consecutive weeks. Retinal vessel degenerate changes, the expression levels of E-Cadherin, N-Cadherin and the mRNA levels of c-kit, CXCR4, MYPT1, SCF, SDF1-α in retina, the levels of SDF-1α and SCF in the peripheral blood and the number of LSK cells expressing c-kit and sca-1 were determined. PBM could significantly inhibit the degenerative change of diabetic retinal vessels, decrease the expression levels of E-Cadherin and N-Cadherin and the mRNA levels of c-kit, CXCR4, MYPT1, SCF, SDF1-α and increase VEGF mRNA levels in retina. PBM could also increase the levels of SDF-1α and SCF in the peripheral blood and the number of LSK cells expressing c-kit and sca-1 in diabetic mice. PBM at 4 min/day for 20 consecutive weeks significantly inhibit the degenerative change of diabetic retinal vessels, and PBM is likely to produce its beneficial effects on the retina through promoting the migration of bone marrow stem cells to circulation and diabetic retinal tissue. The present study provides a new therapeutic direction and experimental foundation for the treatment of diabetic retinopathy.