Photobiomodulation therapy for diabetic macular edema : fourier transform infrared spectroscopy study

Abstract EN

Background/Aim Photobiomodulation (PBM) is the application of low-level light that has a beneficial biological effect, such as to relieve pain, to heal existing tissue damage, and to inhibit the development of tissue pathology.

The aim of the current study is to evaluate the effect of PBM therapy on diabetic macular edema (DME) in albino rats as assessed by Fourier transform infrared spectrum.

Materials and methods Twenty-five albino rats with the same sex (200±20 g) were involved in this study.

Diabetes was induced in albino rats after intraperitoneal injection of 55 mg/kg streptozotocin.

The experimental animals were divided into three main groups: (i) control group, (ii) DME group that did not received any treatment, and (iii) DME group that was exposed to two sessions/week of 660-nm low-level laser source for a period of 2 weeks.

The rat’s eye received a power of 5 mW/cm2 for 90 s, with a total energy of 450 mJ, in each session.

Fourier transform infrared spectrum analysis was applied after 2 weeks for comparison between the diabetic and PBM-treated groups.

Results The results confirmed that DME was associated with changes in the retina structure that appeared after receiving a single dose of streptozotocin 55 mg/kg.

These changes obviously appeared in the NH–OH as shown in strO–H (P<0.05), strO–Hsym (P<0.01), C–Hring (P<0.01), CH stretching, fingerprint, and amide I regions.

Treatment with PBM significantly improved most of the amide I components except the first peak of β-turn and formation of new bands corresponding to β-sheet.

Conclusion The treatment with PBM by using low-level diode laser was associated with different beneficial effects on the retina constituents, as showed by the obvious improvement in the retinal protein secondary structure using Fourier transform infrared analysis.

More PBM sessions and long-term follow-up are needed for use of the PBM therapy as a treatment method.