The impact of high-intensity laser therapy on oxidative stress, lysosomal enzymes, and protease inhibitor in athletes.

The aim of the study was to assess the effect of one session of high-intensity laser therapy (HILT) on the levels of selected oxidative stress parameters, lysosomal hydrolases, and anti-inflammatory serine protease inhibitor in the peripheral blood of amateur athletes with torn or pulled tendons of the ankle or the knee joint. The group of injured athletes comprised 16 males and females aged 16.3 ± 1.3 years, while the control group of 14 healthy, noninjured amateur athletes of both sexes (controls; age 17.4 ± 4.6 years). Material for the study was peripheral blood taken at three study time points: Immediately before, 30 min after, and 24 h after HILT intervention. In plasma and erythrocytes, thiobarbituric acid reactive substances (TBARSpl and TBARSer, respectively) were determined. In erythrocytes, the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were measured. In serum, the activity of acid phosphatase (AcP), arylsulfatase (ASA), cathepsin D (CTS D), and α1-antitrypsin (AAT) were determined. Among oxidative stress parameters, only the CAT activity significantly decreased 24 h after HILT compared to measurement 30 min after the treatment in the injured individuals (P < 0.01), while the GPx activity in that group was meaningfully higher 30 min after HILT compared to controls (P < 0.05). Thirty min after the intervention, the activities of AcP and ASA were lower in the injured participants compared to the uninjured ones (P < 0.01 and P < 0.05, respectively). The CTS D activity was lower 30 min and 24 h after HILT in both groups (P < 0.001) and did not differ significantly between them (P > 0.05). Moreover, the study showed statistically significant linear relationships between the TBARSer concentration and the SOD activity before HILT in the healthy participants (r = -0.6, P = 0.021) and 24 h after HILT in the injured ones (r = 0.6, P = 0.025). In the noninjured athletes before HILT, the CTS D activity linearly correlated with the AAT activity (r = -0.70, P = 0.005), and 30 min after the treatment, with the AcP activity (r = 0.5, P = 0.041). 24 h after the HILT intervention, the CTS D and AcP activities were also correlated in the injured athletes (r = 0.8, P = 0.002). The study suggests that one HILT intervention does not significantly influence the redox equilibrium but stabilizes lysosomal membranes.