The ileum part is the optimal plastic material for the reconstruction of the artificial bladder in comparison with other parts of the gastrointestinal tract. It has the best ability to adapt functioning in new conditions due to its minimal metabolic disturbances. A study included the investigation of the characteristic features of the structural changes in the mucous membrane of the mini-pigs artificial bladder in an experiment six months after performing ileocystoplasty. Studies were conducted on 18 female mini-pigs, aged 4–15 months, weighing 8–15 kg. Modeling of the artifivial bladder in experimental animals was performed by cystectomy, followed by ileocytoplasty. The material was examined 6 months after surgery. The analysis of the material showed that the columnar cells have high regenerative capabilities in the neocyst, but under conditions of environmental change that affects them for 6 months, probably negatively, they try to function and restore structures, but with prolonged exposure to urine, some of them are damaged. At the same time, enterocyte modification processes take place in the neocyst. Its metaplasia occurs, and the cells adapt to the new conditions of existence, accepting signs of bladder urothelium. The ultrastructural changes of the connective tissue cells occur in the lamina propria, which indicate manifestations of an allergic reaction, probably to substances that come from the cavity of the formed bladder because they are not characteristic of this tissue. The processes of chronic inflammation and allergic reaction with the active inclusion of compensatory-restorative processes at various levels of the pathogenetic chain prevail in the mucosa of the neocyst.
