Can laser therapy modify the secretion of the tissue-type plasminogen activator and its inhibitor in an endothelial cell culture under hyperglycemia?

Introduction :  The effect of low-level laser therapy on the secretion of tissue-type plasminogen activator (t-PA) and its inhibitor (PAI-1) in an endothelial cell (EC) culture under hyperglycemia is the subject of the presented work.  Hyperglycemia associated with diabetes causes vascular EC dysfunction. Low-level laser therapy is a good method to support the pharmacological treatment of diabetes complications. Materials and methods :  We used lasers of 2 wavelengths: 635 nm and 830 nm with dose of 2 J/cm2. The experiment was performed  in vitro  in 4 groups of EC: 1 – no glucose in culture medium, no irradiation (control), 2 – glucose, no irradiation, 3 – glucose, laser 635 nm, 4 – glucose, laser 830 nm. After 2 irradiations, cells were counted and the t-PA and PAI-1 antigen (Ag) concentration in the supernatant was measured. Results :  In group 2, we observed a statistically significant lower number of cells (p < 0.0001) and a higher concentration of t-PA:Ag and PAI-1:Ag (p < 0.05) compared to the control group. However, in groups 3 and 4, the number of cells increased and the concentration of t-PA:Ag and PAI-1:Ag decreased compared to group 2 and nearly reached the values in the control group. Conclusions :  Hyperglycemia affects the fibrinolytic activity of ECs which is manifested by a significant increase in t-PA:Ag and PAI:Ag concentrations – recognized markers of endothelial damage. Irradiation of ECs by a low-power laser caused attenuation of the adverse effects of hyperglycemia. A tendency towards a decrease in t-PA:Ag and PAI-1:Ag concentration in the supernatant was observed with a significant increase in the number of cells to values close to control.