Malkov I. Reactive and regenerative properties of tissue components of anterior abdominal wall in experimental alloplasty of the ventral hernia

The dissertation is devoted to the determination of tissue, cellular and ultrastructural changes in the muscular, connective tissue and microvascular components of the anterior abdominal wall in the experimental alloplasty of ventral defects, taking into account the influence of polypropylene material and the biomechanical tension of tissues. On the basis of quantitative histological, electron microscopic and immunohistochemical analysis of the changes occurring in the tissues after the plastics of the experimental defect of the anterior abdominal wall in rats, it has been proved that the presence of polypropylene prosthesis after aloplasty of the experimental defect in moderate degree increases the duration of the course of the early inflammatory processes, but in the distant postoperative period provides adequate and complete rebuilding of the scar and muscle tissue structure, including microcirculatory components. It is shown that the tension of the muscular-aponeurotic layer of the abdominal wall is a significant factor that causes an increase in the timing of the scarring and also causes stable degenerative changes in the muscular and aponeurotic structures. This is accompanied by a lack of microcirculation, dystrophic phenomena in the muscle fibers, hyperplasia of the connective tissue components of the muscular-aponeurotic layer of the anterior abdominal wall with the most pronounced pathological changes from the 10th day to the end of the 3rd month after the autoplasty and aloplasty of the ventral defect. The use of a polypropylene prosthesis in the absence of biomechanical tension of muscular-aponeurotic structures allows to significantly optimize the course of restorative-adaptive and regenerative processes in the first three months of the postoperative period. By electron microscopy it was determined that early tissue reactions within 3 days after ventral defect plastics include not only manifestations of acute aseptic inflammation with related changes in microvessels, but also ultrastructural rearrangements of muscle-aponeurotic structures in the wound healing zone. During 10 days after the plastics of the experimental ventral defect there is a significant reduction of ultrastructural changes in the microvessels and muscle-aponeurotic structures, but in response to the presence of the polypropylene prosthesis, the components of the anterior abdominal wall continue to detect disturbed localization of myofibrils and mitochondria in the muscle fibers, damage to the endothelial cells of the hemocapillaries. Even with the extension of the terms of inflammatory-destructive changes of cells in the healing zone, the presence of the prosthesis does not violate the general course of intracellular regenerative processes in the muscle, connective tissue and microvascular components during 1 year after alloplasty. It is shown that after plastics of large ventral defect, early reactive tissue changes include expressive electron microscopic manifestations of acute aseptic inflammation and degenerative changes in muscle-aponeurotic structures in conditions of significant tissue tension in the wound healing zone, regardless of the presence or absence of prosthesis material. The use of polypropylene mesh without tension reduces the severity of early cell damage. In the conditions of significant biomechanical tension within 1-3 months after the plastics of a large ventral defect, the destructive ultrastructural changes of the microvessels and muscle-aponeurotic structures are maintained, regardless of the effect of the polypropylene mesh. The require of significant tension in tissues creates surroundings for the full integration of the prosthesis into the muscular-aponeurotic structures of the anterior abdominal wall. Immunohistochemical characteristic of markers VEGF and CD34 for 1 year after hernioplasty of a large ventral defect under situation of tension of tissues testifies to the preservation of pathological changes of microcirculation and violation of the microvascular component. On the contrary, the prevention of biomechanical tension in alloplasty leads to a gradual normalization of the distribution and expression levels of markers VEGF and CD34 in the muscles of the anterior abdominal wall.