HISTOMETRIC AND ULTRASSTRUCTURAL ORGANIZATION OF NERVOUS MUSCULAR EXTRACTION OF THE MUSCULARS OF THE FRONTAL WALL OF THE LIVER AT THE POST-OPERATIVE VENTRAL

Actuality. Ventral hernias are known to reduce dramatically the function of the muscles of the anterior abdominal wall due to muscle fiber hypotrophy. The question of the restructuring of the peripheral nervous system (neuromuscular endings and axo-muscular synapses) remains poorly understood in these circum-stances. The aim of the study was to study the dynamics of histo-ultrastructural changes of the axo-muscular synapses of the direct muscle of the abdomen in postoperative ventral hernia. Materials and methods of research. In 10 Wistar rats, ventral hernia was simulated and removed from the experiment after 30, 60, and 90 days to examine the peripheral nerve apparatus of the direct abdominal muscle using histological and electron microscopic methods. The control group consisted of 10 intact outbred male rats aged 120 days. Histological and electron microscopic techniques were used to study the anterior abdominal muscles. Results. According to the results of histometric and electron microscopic examination of neuromuscular endings, it was established that at all observation times terminal nerve fibers in the area of ventral hernia respond to postoperative trauma with characteristic destructive-dystrophic changes. The pattern of these changes at different times after ventral hernia modeling is shown. Comparison of the ultrastructure of the terminal neu-roleocytes of control and experimental animals revealed a number of characteristic changes that indicate the development of a stress response in these cells in response to stretching of muscle fibers by the elements of the hernia sac. Electron microscopic examination revealed that in myelin fibers the periaxonal space expands, in the axoplasm the degree of aggregation of filamentous-tubular structures increases. In axillary synapses, 60 days after the start of inguinal hernia modeling, most of the folds of the postsynaptic membrane, the expansion of the synaptic cleft, and the growth of processes of the terminal neuroleocytes develop, disintegrate. In axillary synapses, terminal branching is destroyed, causing the presynaptic pole of neuromuscular endings to cease to exist. In these areas, the remains of the axoplasm are observed. It is known that a permanent sign in all forms and degrees of neuro- and myopathy is the lack of active impulse transmission in the area of the presynaptic membrane. The results obtained by us show that in the inguinal hernia, impaired impulse transmission, which is due to profound degenerative changes in postsynaptic membranes, which exacerbate the effects of other adverse factors on trans-verse development, is compounded by the existing de-structive changes of the preterminal fibers and axonal terminals. Due to the total destruction of the ultrastruc-ture of the axo-muscle synapses, no histometric studies were performed at the 90th day of the experiment. Conclusions. Dystrophic-destructive changes in neuromuscular endings are observed in the postoperative suture area in the early period after modeling of ventral hernia, which in the later period is combined with the processes of secondary muscle re-regeneration. Increased axonal spurs are accompanied by an increase in the size of the motor units, which, against the background of underdeveloped axo-muscle synapses, leads to a decrease in the power capacity of the muscles of the anterior abdominal wall. This can be a morphological substrate and cause postoperative ventral hernias.