Peritoneal Free Autologous Fat Graft for the Control of Pulmonary Air Leaks in Emphysematous Rat Lungs

Abstract

Persistent pulmonary air leak is the most frequent complication after lung resection, resulting in an increase in postoperative morbidity and mortality. We evaluated the viability, integration, and efficacy of a free peritoneal fat graft as a method for controlling air leak in normal and emphysematous rat lungs. Sixty Wistar rats were divided into two groups: elastase-produced lung emphysema (n=30) and control (normal) lungs (n=30). Pulmonary air leak was produced by puncture of the right lower lobe, and aerostasis was attempted by means of intrapulmonary injection of autologous free peritoneal fat graft. Rats in each group (n=6) were randomly allocated to subgroups and were sacrificed at 7, 14, 21, 30, and 60 days. Then, lungs were removed for histology, morphometry, vessel identification and counting, and immunohistochemistry for caspase 3, vascular endothelial growth factor, and factor VIII. Tissue integration of the free fat grafts was found in all animals in both groups. Vessels stained with India ink inside the fat grafts were present at all assessment periods in both groups. Vascular endothelial growth factor expression was significantly higher in all periods in the emphysema group compared with normal lungs (p<0.001). There was a significant increase in caspase 3 expression in the emphysema group at 7, 21, 30, and 60 days (p<0.001). Factor VIII showed a significant increase (p<0.001) at 30 and 60 days in emphysematous lungs. The use of free peritoneal fat graft was able to control the air leaks in normal and emphysematous rat lungs, with persisting graft viability for as long as 60 days after implantation.