Effects of infrared laser radiation on qualitative and quantitative indices of a regenerating skeletal muscle in the age aspect

Laser light can stimulate cell proliferation and restoration of various tissues after injury. The age aspect of laser irradiation effects at muscle regeneration, in particular the response of myosatellitocytes and myocytes, remains unexplored. The purpose of the research was to study the effect of laser light at the area of nuclei and the number of myosatellitocytes, as well as the area of myocyte nuclei in a model of posttraumatic regeneration of skeletal muscle in animals of different age groups. Material and methods . 32 laboratory mongrel rats, divided into 2 groups – young (3 months) and old (30 months) – were taken into the experiment. The formed surgical injuries at the caviar muscle on the left limb were experimental; they were irradiated with laser light (1060 nm, power 2.0 W, continuous mode, exposure 60 s, one time); injuries on the right limb were dynamic control. The animals were removed from the experiment on days 7 and 14. Tissue samples were fixed in formalin, histological sections were prepared, hematoxylin-eosin and Van Gizon picrofuxin were stained, and a digital image of objects was morphometrically analyzed. Results . It was found that after laser irradiation of the muscle, the area of nuclei and the number of myosatellites increase significantly compared to the control group, regardless of animal’s age. The response to myocyte nuclei to laser light was seen in both age groups, but it was significantly higher in younger animals. The obtained results demonstrate that laser radiation has the potential to activate muscle regeneration regardless of animal’s age.