At the present stage of development of herniology there is an active search for ways to increase the effectiveness of various methodological approaches to the plastic repair of ventral hernias in both experimental and clinical areas. Therefore, the aim of the study was to establish the patterns of morpho-functional organization of the rectus abdominis in normal rats, in animals with simulated ventral hernia, prone implant hernioplasty and electrical stimulation. Morphological study was performed on material obtained from 83 white male rats weighing 180-200 g. The results of the analysis of neovasculogenesis in the area of scar formation are of great interest. In animals of group 1, the density of capillaries was characterized by a clear tendency to increase during the 1st month of the experiment, after which there was a phase of decreasing values till the 90th day. In contrast, in group 2 animals, the number of capillaries increased from the 30th day of the experiment, but remained lower than the results in intact group even on the 90th day. This fact, of course, indicates more adequate hemodynamic characteristics of the scar tissue of animals of group 2. Significant microcirculation disorders and surgical damage to the anterior abdominal wall during the simulation of ventral hernia and its hernioplasty lead to vacuolar dystrophy, partial and colliquative necrosis of muscle fibers (MFs) on the 10-30th days. On the 60-90th days, there are compensatory-restorative processes in MFs, which are more pronounced in animals of group 2. In contrast, group 1 animals showed high connective tissue content, decreased capillaries, and the presence of focal destructive changes in MFs, leading to atrophy and sclerosis of the rectus abdominis. 10 days after the start of ventral hernia modeling in animals of group 1, the endings of myelinated nerve fibers (MNFs) are without terminal branches of the axon due to their injury, while in animals of group 2 the neuromuscular endings (NMEs) are preserved, but the number of branches of the terminal axon is decreased by 1.7 times, which leads to a decrease in the area of NMEs by 47% and 31%, respectively. On the 30th day, periaxonal progression and activation of degenerative processes are observed in most MNFs and neuromuscular synapses (NMSs). On the 60-90th days, in group1 animals a further decrease in the area of NMEs and destructive changes in NMSs were observed. It was accompanied by a decrease in muscle bioelectrical activity and a simultaneous increase in polyphasic and spontaneous activity compared to intact animals. Such changes develop as a result of demyelination and are confirmed by histo- and ultrastructural studies. In contrast, in group2 animals the restructuring of the NMEs of the rectus abdominis muscle on the 60-90th days indicates compensatory-reinnervation processes, which are manifested by the increase in the area of NMSs and restoration of its structural components. During the regeneration of the NMEs, there was a gradual increase in the bioelectrical activity of the muscle according to EMG. Due to ES with different frequency in animals of group 3, compared with group 2 rats, there was a decrease in the relative area of connective tissue by 35.7%-59.4% with an increase in the relative area of MFs by 12.3%-27.1%. The number of capillaries per 0.1 mm2 of rectus abdominis area, compared with group 2 animals, increases by 3.7%-19.3%; the values in subgroup 3a probably do not differ from those of intact animals. In animals of group 3, compared with group 2, the area of MFs increases by 16.8%-50.8% (p<0.05). ES leads to increased cellular and intracellular regeneration. Thus, in animals of subgroup 3a, newly formed MFs are observed due to myosateliocyte differentiation. The use of ES promoted the development of reinnervation processes in the rectus abdominis of group 3 animals. The area of NMEs in animals of subgroup 3a is the largest in group 3 and is close to intact values, which is directly proportional to the increase in the number of branches of the motor axon. Submicroscopic examination of animals of subgroups 3b and 3c reveals periaxonal edema and defibering of the lamellae of the myelin sheath of the MNFs. Thus, the ES with a frequency of 10 Hz is the most effective of the modes used in the experiment and leads to the restoration of quantitative morphological parameters of the rectus abdominis. Key words: rectus abdominis muscle, neuromuscular synapse, hemomicrocirculatory tract, ventral hernia, electromyography. Branch-Medicine.
