Damage to the abdominal organs after the action of explosion factors (shock blast wave, striking elements of the explosive device, secondary shells, chemical, and thermal factors) is a common clinical situation not only in Ukraine but also around the world. The small and large intestines are the most vulnerable to the impact of a shock blast among the abdominal organs. However, closed explosion-induced traumatic injuries of internal organs are difficult at the stages of the diagnostic process, which is the reason for the untimely provision of specialized medical care. Untimely detection of explosion-induced trauma to the abdominal cavity, in particular the intestine, leads to serious consequences, namely peritonitis, intra-abdominal bleeding, because of traumatic perforations of the intestine and rupture of intra-abdominal vessels. This is especially true of low-intensity explosions when a person does not pay attention to them and does not consult a doctor. However, as for explosion-induced intestinal injuries, such diagnostic panels are not used. During the research, the role of modeling the pathological condition, identifying the timing, causes, and mechanism of disturbances in the morphogenesis of the intestine, its wall, and structural elements or components increases, which allows to develop of a model and help determine corrective measures of shock waves. In the available literature, we have not been able to find comprehensive studies using general histological techniques, immunohistochemistry and electron microscopy of the small intestine in the above pathology. This justifies the relevance of this study and the feasibility of its conduct.. Our research aimed to study the morphological patterns of morphogenesis of the small intestine and its structural components of experimental animals in barotrauma using general histological techniques, immunohistochemistry, and electron microscopy. To study the structures of the small intestine, the following methods were used: general histological; electron microscopy; immunohistochemical markers of HIF-1a hypoxia, LC3b autophagy, and eNos endothelial dysfunction to determine modification; methods of variation statistics. For the first time a complex morphological, general histological, immunohistochemical study of the fine organization of the structural components of the small intestine of rats after shock-wave exposure with different terms after its action. The model of shock-wave influence is received. Under the conditions of barotrauma simulation on the anterior abdominal wall of experimental animals, diffuse changes in the wall of the small intestine are observed, which is accompanied by edema and exfoliation of mucous, submucosal and serous membranes in the first hour. Thickening of the intestinal wall layers occurred due to intercellular edema, edema of stromal elements. The general inflammatory reaction in the layers of the intestinal wall was combined with focal hemorrhages, focal destruction of the basement membrane, and eosinophilic infiltration in the mucous and submucosal membranes. A comparative ultramicroscopic study using electron microscopy was performed for the first time, which showed that microthrombus formation is observed in the early stages after barotrauma, which can lead to severe consequences in the late period. Morphological signs of violation of intramural hemodynamics of the small intestine depending on the observation period, starting from the first day of observation and during the study period, were manifested by paresis of arterioles and venules with the development of erythrocyte vascular stasis. When evaluating the expression of markers of hypoxia HIF-1a, autophagy LC3b and endothelial dysfunction eNos in the small intestinal wall after barotrauma showed differences in the intensity of staining depending on the time of observation. The most intensive accumulation of these markers occurred on the 7th day of the post-traumatic period. The results of the study contribute to the expansion of ideas about the basic principles and specific changes of the small intestine in the conditions after the shock-wave exposure; make it possible to predict the effects of the impact on the structural components of the small intestine in explosive injuries and the correction of this condition. The obtained results on the morphogenesis of the small intestine after the shock-wave exposure of experimental animals make it possible to form an idea of the morphogenetic changes of the small intestine and its blood circulation, which we can predict and correct.
