Free transplantation of fat autografts expanded by tissue expanders in rats

Inguinal fat pads of 28 rats were expanded by tissue expanders for 10 days and transplanted to the back of the same animal. The non-expanded contralateral inguinal fat pads were also transplanted and served as controls. Histology showed that adipocytes lose their lipid droplets under mechanical pressure; the expanded adipocytes have an elongated contour with a central nucleus. By the end of the expansion period, the thickness of the fat pads had decreased by 53%. One week after transplantation, expanded fat grafts had regained their previous volume with little sign of necrosis. Among normal adipocytes numerous smaller cells, containing multiple vacuoles, were seen. In contrast, about 25% of the substance of the non-expanded control fat graft consisted of necrotic oil cysts. These findings indicate that pre-expanded fat grafts survive better.