Спортивная медицина: наука и практика (Aug 2020)
Cytogenetic abnormalities in thymus cells as a possible side effect of combined skeletal muscle laser therapy (experimental study)
Abstract
Objective: the functional analysis of the thymus during a course of laser therapy of the calf muscles of adult rats. Materials and methods: thymus mass, proliferative activity (mitotic index, MI) and possible cytogenetic effect on thymus cells (chromosome aberrations – CA) were studied on 25 adult rats. Irradiation conditions: pulsed infrared (890 nm, 1500 Hz, output power 8 W) and continuous red (632.8 nm) laser radiation. 5 series of experiments were carried out: study of thymus in control rats with non-irradiated legs (1st series); 1 day (2nd series) or 1 month (3rd series) after completion of combined laser irradiation of both calves (5 exposures with daily alternation); 1 day after exposure to only infrared (4th series, 5 exposures) or only red laser radiation (5th series, 5 exposures) with 1-2 day intervals. Chromosomal aberrations were determined by the ana-telophase method. Results: a thymus weight reduction tendency, reduction of the cortex and increased CA were observed in the 2nd series (Р<0.01). MI of thymocytes did not change. The 3rd series showed the increasing thymus mass tendency and increasing of the width of the cortical layer. MI was lower (Р<0.1); CA decreased (Р<0.01) and approached to control. The studied parameters of the 4th series were practically unchanged in comparison with the control. Only non-considerable increase of CA could be noted. The 5th series showed the increase of the thymus mass (Р<0.01) and decrease of CA (Р<0.01). The structure of thymus and MI thymocytes did not differ from control. Conclusions: the destabilization of the chromosome apparatus of thymus cells and the appearance of CA may occur during combined intensive laser irradiation of skeletal muscles, apparently, as a result of exceedanse of the permissible therapeutic norm. There is a gradual recovery in the following. After only infrared laser irradiation, the cytogenetic effect (CA) did not increase, after exposure to red laser radiation, a stimulating effect was observed including reduction of the number of spontaneous CA in the thymus.
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