In vitro effects of low-intensity infrared laser irradiation on oxidative stress biomarkers in blood samples from diabetes mellitus patients

Purpose: The biological effects of low-intensity laser irradiation on oxidative damage and free radical-induced processes in the blood of patients with diabetes mellitus have not been studied yet. The aim of this study was to evaluate the time-and dose-dependent effects of low-intensity infrared (IR) irradiation on biomarkers of lipid peroxidation, oxidative modification of proteins (aldehydic and ketonic derivatives), and total antioxidant capacity in blood of healthy individuals and patients with diabetes mellitus in vitro. Methods: Blood samples were collected from the diabetes patients and healthy individuals and exposed to low -intensity infrared irradiation in vitro. The samples were exposed to 1-, 5-, and 9-min IR laser pulses with the wavelength of 0.89 nm at different pulse repetition frequencies (0; 50; 150; 600; 1500 Hz) and moderate radiation power (0; 50; 100 mW). The biomarkers of oxidative stress, i.e. 2-thiobarbituric acid reactive substances (TBARS), aldehydic and ketonic derivatives of oxidatively modified proteins, and total antioxidant capacity (TAC), were measured and analyzed in the samples of the exposed whole blood. Results: Compared with the blood from the healthy controls, the lipid peroxidation analysis revealed 7 combinations of irradiation impact in the blood from the diabetes patients resulting in a decrease in lipid peroxidation processes, especially after the 9-min exposure. The analysis of oxidatively modified proteins demonstrated that laser light is mainly involved in the prevention of protein oxidation at moderate radiation power (50 and 100 mW), different pulse repetition frequencies (0; 50; 150; 600; 1500 Hz), the 9-min exposure and resulting in a decrease in lipid peroxidation processes. The analysis of the total antioxidant capacity revealed a predominantly positive effect of the low-intensity infrared irradiation. Conclusions: These findings suggest potential involvement of blood dysfunction in the pathologic process of diabetes and provide insight into potential therapeutic targets of low-intensity IR laser irradiation for diabetes patients.