LAUSR

INTRODUCTION diaphragmatic injury is a challenge for surgeons. It is an injury that can be isolated. It is frequent in penetrating thoracoabdominal trauma. It represents a diagnostic challenge and the ideal approach is not yet well established. The occurrence of spontaneous healing of these injuries is still much discussed and even more, if it does, what is the healing mechanism? OBJECTIVE to macroscopically and histologically evaluate the natural evolution of perforation and cutting wounds equivalent to 30% of the left diaphragm. METHOD 50 specimens of rats underwent a surgical procedure and, after 30 days, were euthanized and those that presented scar tissue in the diaphragm, the samples were submitted to histopathological study, using the hematoxylin and eosin stains, Massons trichrome and Picrosirius to assess the presence of collagen or muscle fibers (hyperplasia) in the scar. RESULTS it was found that healing occurred in diaphragmatic injuries in 90% of rats. We also observed the presence of fibrosis in all analyzed samples. CONCLUSION Spontaneous healing occurred in most diaphragmatic injuries and the inflammatory reaction represented by the presence of fibrosis and collagen deposition was observed in all our samples. Muscle fiber hyperplasia did not occur.