EFFECT OF HENE LASER ON SKELETAL MUSCLE STRUCTURE AND FUNCTION AFTER NERVE INJURY OF VARIOUS DEGREES OF SEVERITY

Objective - to investigate the effect of low-intensity laser radiation on the mass, structure and function of gastrocnemius muscles in rats after varying degrees of destruction of the tibial nerve. Materials and methods. The work was carried out on laboratory outbred adult male rats (n=20). The tibial nerve was damaged at a distance ≈1 cm from the site of its the entry of into the gastrocnemius muscle by cutting or fragment removal. Laser irradiation of the area of nerve injury and the whole gastrocnemius muscle was performed for a month (10 sessions) with a HeNe laser (at a wavelength of 632.8 nm). On the 30th day after the operation, the mass and contractile function of the muscles were determined. Histological analysis of the regenerates was perormed in 32 sections at deifferent levels of the gastrocnemius muscles. Results. After nerve cutting, the mass of regenerates and the structure were preserved to a significant extent. All the regenerates preserved their contractile function during nerve stimulation. After the loss of a nerve fragment, a degeneration of muscle tissue and proliferation of connective tissue were markedly increased, and regenerates responded by contraction only to direct stimulation. Laser therapy contributed to a greater preservation of the mass and structure of gastrocnemius muscles, and after both types of nerve injury to approximately the same extent. Contraction of regenerates during stimulation of the nerve was noted not only after its cutting, but also after the loss of the fragment. Conclusions. In both types of trauma of the tibial nerve, laser therapy of denervated gastrocnemius muscles had a positive effect on their mass, structure and function. Moreover, restoration of the nerve function after the loss of its fragment was observed without the implantation of the biological scaffold in the area of injury.

gastrocnemius muscle, tibial nerve, injury, HeNe laser