The effect of human umbilical cord-derived mesenchymal stem cell transplantation on the reparative properties of muscle-aponeurotic defect reconstruction in the anterior abdominal wall of rats

Abstract

Postoperative ventral hernias represent a significant challenge in modern surgery, arising as complications following abdominal operations due to weakness or defects in the musculoaponeurotic structure of the anterior abdominal wall. Mesenchymal stem cells (MSCs) possess high reparative potential due to their paracrine ability to stimulate the regeneration of damaged recipient tissues. Objective. To investigate the effect of intraperitoneal transplantation of human umbilical cord-derived MSCs on the regeneration of muscle fibers in the area of musculoaponeurotic defect repair in the anterior abdominal wall of rats. Materials and Methods. A surgical model of a musculoaponeurotic defect (2 cm in diameter) in the anterior abdominal wall was created in 72 white rats. Animals were divided into four groups based on the method of defect correction: 1) repair with autologous tissues; 2) repair with autologous tissues combined with MSC injection; 3) repair using a polypropylene mesh; 4) repair using a polypropylene mesh combined with MSC injection. Human umbilical cord-derived MSCs were isolated using enzymatic methods, validated by flow cytometry for surface marker expression, and administered intraperitoneally at a dose of 1 million cells per kilogram of body weight. On the 10th and 30th days, histological analysis of tissue samples from the repair site was conducted, assessing the presence of granulation tissue, collagen fibers, newly formed connective tissue, and cellular infiltration. Morphometric comparisons included the relative areas of granulation and fibrous reticular tissue, microcirculatory vessels, and counts of neutrophilic leukocytes, lymphohistiocytic elements, and fibroblasts per square millimeter of section. Results. In Group 1, the repair area demonstrated loose connective tissue rich in fibroblasts and histiocytes. In Group 2, a significantly reduced cellular reaction was observed, along with the formation of denser connective tissue bundles; transverse striation of muscle fibers was more clearly visualized at the sites of damage. On day 10, the granulation tissue area was 34.6% smaller, and the microcirculatory vessel area was 15.9% smaller compared to Group 1, and 28.1% and 57.2% smaller, respectively, compared to Group 3. In Group 3, granulation tissue formed at sites of necrosis and muscle fiber destruction. The best results were observed with the combination of polypropylene mesh and MSCs, where complete resolution of the inflammatory response and scar tissue formation was recorded. In Group 4, on day 10, the granulation tissue area was 2.5 times smaller than in Group 1 and 1.3 times smaller than in Group 2. The relative area of microcirculatory vessels was 1.8 times smaller than in Group 1 and 1.3 times smaller than in Group 2, whereas the fibrous reticular tissue area was 3.2 and 1.2 times larger, respectively. By day 30, granulation tissue, microcirculatory vessels, and leukocytes were no longer detected. The fibrous reticular tissue area was the largest among all groups at this time point. Conclusion. Intraperitoneal transplantation of human umbilical cord-derived MSCs in conjunction with polypropylene mesh repair of musculoaponeurotic defects in the anterior abdominal wall of rats improves regeneration at the defect site and promotes faster healing.