Low-Level Laser Therapy with 670 nm Alleviates Diabetic Retinopathy in an Experimental Model

Salwa Abdelkawi Ahmed; Dina Fouad Ghoneim; Mona Ebrahim Morsy; Aziza Ahmed Hassan; Abdel Rahman Hassan Mahmoud

doi:10.4103/joco.joco_29_20

Low-Level Laser Therapy with 670 nm Alleviates Diabetic Retinopathy in an Experimental Model

J Curr Ophthalmol. 2021 Jul 5;33(2):143-151. doi: 10.4103/joco.joco_29_20. eCollection 2021 Apr-Jun.

Authors

Salwa Abdelkawi Ahmed¹, Dina Fouad Ghoneim², Mona Ebrahim Morsy³, Aziza Ahmed Hassan², Abdel Rahman Hassan Mahmoud²

Affiliations

¹ Department of Vision Science, Biophysics and Laser Science Unit, Research Institute of Ophthalmology, Giza, Egypt.
² Department of Medical Application of Laser, Ophthalmic Unit, National Institute of Laser Enhanced Science, Cairo University, Giza, Egypt.
³ Department of Medical Application of Laser, Photobiology Unit, National Institute of Laser Enhanced Science, Cairo University, Giza, Egypt.

Abstract

Purpose: To evaluate the effects of low-level laser therapy (LLLT) on the retina with diabetic retinopathy (DR).

Methods: Eight Wistar rats were used as a control group, and 64 rats were injected intraperitoneally with 55 mg/kg of streptozotocin to induce diabetes and served as a diabetic group. After the establishment of the DR, the rats were separated into (a) 32 rats with DR; did not receive any treatment, (b) 32 rats with DR were exposed to 670 nm LLLT for 6 successive weeks (2 sessions/week). The retinal protein was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, total antioxidant capacity (TAC), hydrogen peroxide (H₂O₂), and histological examination.

Results: LLLT improved retinal proteins such as neurofilament (NF) proteins (200 KDa, 160 KDa, and 86 KDa), neuron-specific enolase (NSE) (46 KDa). Moreover, the percentage changes in TAC were 46.8% (P < 0.001), 14.5% (P < 0.01), 4.8% and 1.6% (P > 0.05), and in H₂O_2, they were 30% (P < 0.001), 25% (P < 0.001), 20% (P < 0.01), and 5% (P > 0.05) after 1, 2, 4, and 6 weeks, compared with the control. DR displayed swelling and disorganization in the retinal ganglion cells (RGCs) and photoreceptors, congestion of the capillaries in the nerve fiber layer, thickening of the endothelial cells' capillaries, and edema of the outer segment of the photoreceptors layer. The improvement of the retinal structure was achieved after LLLT.

Conclusion: LLLT could modulate retinal proteins such as NSE and NFs, improve the RGCs, photoreceptors, and reduce the oxidative stress that originated in the retina from diabetes-induced DR.

Keywords: Diabetic retinopathy; Hydrogen peroxide; Low-level laser therapy; Retinal protein; Total antioxidant capacity.