Abdominal Hernia Repair with Bovine Pericardium Seeded with Mesenchymal Stem Cells in Wistar Rats

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Background: Biological membranes demonstrate superiority over synthetic ones for its biocompatibility and strength in the reduction of abdominal hernias. Recents tissue engineering researches add mesenchymal stem cells to biological membranes with the purpose of obtaining additional cellular proliferation and consequent muscle regeneration, using biological membranes as cellular scaffolds. This article aimed to study the infl uence of mesenchymal stem cells in muscle regeneration in abdominal hernias, reduced with biological membranes.Materials, Methods & Results: Adult Wistar rats underwent abdominal hernia-inducing. They were divided into two groups as to the form of treatment for the reduction of hernia: stem cells associated with biological membranes or only biological membranes. After the treatment the macro and microscopic reviews were carried out in days seven, 14 and 60 postopera-tively. Preparation of bovine pericardium with glycerin 98% presented effi ciency in decellularization and conservation, maintaining its strength and avoiding bacterial growth. The mesenchymal stem cells obtained from bone marrow of adult Wistar rats, had capacity of proliferation. The majority of the cells was positive for the expression of surface antigens CD44, CD29 and CD99 and was negative for CD 34. In the differentiation trials, the same cells were able to differentiate into adipocytes and osteocytes. With 24 h from co-cultivating adhesion of mesenchymal stem cells in the membranes was observed. There was no foreign body reaction or contamination of surgical wounds and there was intense postoperative neovascularization on seven days. All animals presented omentum adherence, but no adherence to other organs.There was no statistically difference for the different times in macroscopic assessment: deposition of fi brous tissue, implant integra-tion. The same occurred with the microscopic evaluations between the different treatment groups. The groups of immediate and later repair presented different responses to treatment.Discussion: The use of rats as animal model was satisfactory, being suitable for surgical procedures and assessments of the abdominal cavity. The different results obtained between groups of immediate repair and late repair corroborate with the idea that there is difference between induction and repair models in the same surgery or in different surgeries with the time interval between the two, suggesting the need for methodologies that simulate the hernias chronicity. The cells used were classifi ed as mesenchymal stem cells, because it met all the criteria of Mesenchymal and Tissue Stem Cell Committee of the International Society of Celullar Therapy. The membranes conserved with glycerin 98% demonstrated biocompatibility, because there was no rejection or necrosis, infection or exacerbated infl ammation. However the muscle regeneration was not obtained over the membranes - and the methodological difference in other latest experiments about the membranes decellularization and the co-cultivating - can leads to conclusion that the cells attached to membranes were insuffi cient in number to obtain the desired result. These results suggest the need of new research studies or co-cultivating times and decellularization methods of bovine pericardium for association with mesenchymal stem cells.

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