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The effect of transtraumatic epidural electrostimulation (TEES) above (T5) and below (L2) spinal cord injury in the lower thoracic region (T8-T9) in combination with treadmill exercise in pigs was evaluated using electrophysiological examination methods and behavioral tests. Two weeks after spinal cord injury, motor evoked potentials of m. soleus were recorded during electrostimulation at the level of T5 and L2 segments, which indicated activation of spinal cord structures above and below the focus of injury. After 6 weeks of TEES in combination with physical training, restoration of the characteristics of M-response and H-reflex of the soleus muscle in response to stimulation of the sciatic nerve, improvement of joint mobility, and appearance of voluntary motor activity in the hindlimbs were observed. Neuromodulation with TEES had been proven to be an effective way to stimulate posttraumatic spinal cord regeneration and can be used in the development of a neurorehabilitation protocol for patients with spinal cord injury., (© 2023. Springer Science+Business Media, LLC, part of Springer Nature.)

The development of hypogravitational motor syndrome is an essential negative consequence of weightlessness for humans; an important role in the pathogenesis of this syndrome is played by changes in axons of the spinal tracts. Myelinated fibers and transcriptome of the spinal cord were studied in mice exposed to hypogravity during a 30-day flight on a biosatellite. Morphometric analysis of myelinated fibers of the spinal tracts showed a decrease in the thickness of the myelin sheath. Analysis of spinal cord transcriptome revealed a decrease in the expression of genes involved in the myelination of nerve fibers. These results suggest that the processes of nerve fiber myelination are involved in the development of the hypogravitational motor syndrome under weightless conditions; the 7-day readaptation period was found to be insufficient for reversion of the negative changes in the myelinated fibers of the spinal cord., (© 2023. Springer Science+Business Media, LLC, part of Springer Nature.)

The data obtained by transcriptome analysis of lumbar spinal cord segments, sciatic nerve, and the respiratory diaphragm of the mice performed after a space flight on board Bion-M1 biosatellite were processed by bioinformatic methods aimed at elucidation of the regularities in hypogravity-induced transcriptome changes in various compartments of motor neurons. The study revealed abnormalities of axonal transport in spinal motor neurons provoked by weightlessness. These data agree with the results of electron microscopy examination of the spinal cord in experimental animals. In space group mice sacrificed on the landing day, the content of perinuclear ribosomes in lumbar motoneurons surpassed that in control mice or in the recovery group examined 1 week after the flight. The data corroborate our hypothesis on contribution of axonal transport disturbances into pathogenesis of hypogravity motor syndrome. They can be employed as a launching pad for further study of hypogravity-triggered motor disorder mechanisms in order to elaborate the preventive therapy against the development of hypogravity motor syndrome in space flights.

We studied immunohistochemical and morphometric characteristics of the spermatogenic epithelium in rats against the background of peroral administration of nanoparticles containing titanium dioxide. Substantial degenerative changes in the spermatogenic epithelium were revealed: thinning, disorganization of layers, and detachment of sperm cells from the basement membrane. Immunohistochemical analysis revealed reduced proliferative activity and differentiation potential of epithelial cells, which was confirmed by changes in the expression of Ki-67 and c-kit markers. Our data attest to unfavorable effects of titanium dioxide nanoparticles on the structural and functional characteristics of the reproductive system in male rats leading to spermatogenesis disturbances.

We studied parameters of the frog sartorius muscle contraction initiated by ryanodine receptor agonists in the presence of ROS donors. We hypothesized that sodium nitroprusside and hydrogen peroxide inhibit initiation of contractions by N-ethylmaleimide and that this effect of ROS donors on parameters of N-ethylmaleimide-induced contractions is due to a direct effects of sodium nitroprusside and hydrogen peroxide on N-ethylmaleimide, but not to inactivation of ryanodine receptors in the sarcoplasmatic reticulum of frog skeletal muscle.

Expression of slow myosin in fast lumbrical muscle during unilateral damage to the sciatic nerve was studied in rats. Four weeks after unilateral excision of sciatic nerve segment or its crushing, the content of slow fiber in the lumbrical muscle of the contralateral leg tended to increase (detected using monoclonal antibodies against slow myosin). The extrapyramidal system seems to modulate the phenotype of muscle fibers via motoneurons of the spinal cord, while the compensatory activation of this system manifests in pronounced "deceleration" of both the fast and slow muscles in the hind legs.

Immunohistochemical study with monoclonal antibodies against fast myosin heavy chains showed that excision of a fragment of sciatic nerve does not change, while compression of the nerve decreased the relative content of fast muscle fibers in rat soleus muscle. The content of fast fibers in the muscles of contralateral limbs decreased in both models of denervation. Hence, contralateral limbs cannot be used as the control in experiments with disturbed neurotrophic function. Possible mechanisms underlying changes in the immunohistochemical profiles of experimental and contralateral limbs are discussed.