Analysis of transplant rejection in rabbits aponeurosis

To study the feasibility of heterologous aponeurosis to close the abdominal wall of rabbits emphasizing the rejection process.

This project was approved by the Animals Care Committee of the Faculdade de Ciências Médicas da Santa Casa de São Paulo, and it was carried out at the Experimental Surgery and Technical Unit. Four red female rabbits exchanged abdominal wall aponeurosis with other four white male animals. Two rabbits just had it removed and replaced to be the control group for the healing process. Animals were evaluated once a day, and after 7 days they were sacrificed. Immunohistochemical analysis with CD20 and CD79 was done.

The animals did not have cellulitis, abscess, hematoma, wound dehiscence or herniation. The graft site showed intense hyperemia. The histological analysis showed an inflammatory process with maturing myofibroblasts and collagen ranging from incipient to moderate. The number of vessels was reduced and the inflammatory cells were most plasma cells and macrophages. There were no morphological signs of acute rejection with aggressive vascular endothelial damage. The adjacent muscle showed signs of degeneration with inflammatory centralization of nuclei and cytoplasmic condensation. The immunohistochemical analysis (CD20 and CD79) showed that the inflammatory process was not mediated by lymphocytes. Mann-Whitney nonparametric test showed that the hypothesis of equality (p>0.05) should not be discarded.

There were no postoperative complications (fistulas, dehiscence etc.) and the histological analysis showed nonspecific inflammatory process. The immunohistochemical analysis showed that the inflammatory process was not due to a possible rejection.