[Muscle regeneration and the state of the thymus in adult rats under laser irradiation and alloplasty of the gastrocnemius muscles and diaphragm of newborn rats].

The regeneration of gastrocnemius muscles of adult rats under implantation conditions in areas of muscle tissue damage in newborn rats has been studied. Alloplasty was performed using minced gastrocnemius and diaphragm muscles, which differs at birth in animals by degree of differentiation. The rat-recipient area of alloplasty was subjected to He-Ne laser radiation before operation, with the aim of reducing the immune response to allogenic muscle tissue. It has been shown that the number of regenerating myofibers produced in implanted gastrocnemius muscles is more than in alloplants from diaphragms. However, the formation of cartilage, bone, and adipose tissue foci were observed in the alloplastic region throughout the whole regeneration period. After implantation of minced diaphragm muscles, cartilage nodes were observed only in 7-day regenerates. At the end of observation, in the first instance, the area of muscle trauma in adult rat muscles was replaced by adipose tissue, even in the case of initial laser irradiation. During the implantation of diaphragm muscles, the area of trauma was filled with regenerating muscle tissue.

[Structure peculiarities of muscle regenerates and state of thymus under He-Ne laser therapy in different periods after muscle trauma].

We studied the gastrocnemius muscle regeneration and the reactive changes in thymus of rats under different regimens of He-Ne laser therapy of both operated legs (632.8 nm; 2.5-3.0 mW/cm(2) ). Laser radiation (10 exposures by 3 min within 1-15 days after muscle trauma, 4.5-5.4 J/cm(2) total dose per each leg) stimulated inflammatory reaction, muscle healing and favored preservation of muscle tissue in regenerates. The changes in thymus mass, its histological structure, size of cortex and thymocite mitotic index pointed to the increase of the functional load on thymus and delay of its recovery. The same dose of laser therapy of muscles within 16-30 days after trauma led to the increase of muscle tissue sclerotization in regenerates. The reactive changes in thymus were less pronounced. Threefold decrease of laser dose (10 exposures by 1 min for 1-15 days, 1.5-1.8 J/cm(2)) suppressed inflammatory reaction, impaired the muscle regeneration. The increase of functional activity in thymus was not observed.

Regeneration of skeletal muscles and state of thymus in gamma-irradiated rats under laser therapy of the area of muscle trauma.

The gamma-irradiation of adult rats with a semi-lethal dose (6 Gy) suppressed the posttraumatic regeneration of skeletal muscles and brought about considerable destructive changes in the thymus. The effect of He-Ne laser radiation at a total dose 4.5-5.4 J/cm2 at each operated leg in irradiated rats stimulated the regenerative capacity of skeletal muscle tissue, the healing of skin-muscle wound, and the processes of postradiation recovery in thymus cells (a decrease of chromosome aberrations). The histological structure of regenerates had more muscle pattern. At the same time, the positive dynamics of regenerative processes in muscles was achieved by an increased functional load on the thymus. To stimulate the regeneration of irradiated muscles on the background of a more moderate load on the thymus, the prolonged period of laser therapy and fragmentary distribution of laser exposures during muscle regeneration were preferable. Wound healing improved visibly. Nor formation of chronic radiation ulcers on operated shins was observed.

[Regenerative capacity of muscle tissue and thymus state in irradiated rats exposed to long-term He-Ne laser radiation]. / Regeneratsionnaia sposobnost' myshechnoi tkani i sostoianie timusa u obluchennykh krys v usloviiakh prolongirovannogo vozdeistviia izlucheniia gelii-neonovogo lazera.

We studied the effect of He-Ne laser on regeneration of damaged gastrocnemius muscle in rats irradiated at 6 Gy in conditions of fractional laser energy spread (10 exposures, 3 min for each limb, within 30 days after the operation; 2-3 exposures weekly; 2.5-3.0 mW/cm2 power density; and 9.0-10.8 J/cm2 total dose per animal). Laser radiation stimulated regenerative activity of the skeletal muscle and favored a more even distribution of load on the thymus (a smooth decrease in its weight and slow aplasia). The level of chromosomal aberrations in the thymocytes demonstrated certain instability although remained lower as compared to the control during the whole observation period (60 days).