OBJECTIVETo observe the effects of the fat flap tissues after delay operation on free fat-graft survival rate and duration.

METHODSThe delay operation of fat flaps was performed in the inguinal region of a rabbit. Expression of VEGF was assayed using Elisa method after 12 hours of flap delay. The fat flaps were harvested and cut into pieces after 21 days. A subdermal pocket was created in each side of the dorsal midline of a rabbit, the fat pieces were grafted randomly into a pocket and the normal fat pieces into the other pocket as control. After 1, 3, 6, 9 and 12 months of implantation, the grafted fats were harvested, gross observation, weight measurement and histology were carried out. Number of the vessels stained with anti-CD34 antibody was counted out.

RESULTSVEGF concentrations in flaps were significantly higher (P < 0.05). The density of vessels in experimental groups increased significantly compared with that in control groups at 1 and 3 months, respectively (P < 0.01), and no significant differences in the survival rate of fat tissues between experimental and control groups were observed at 1 and 3 months (P > 0.05). The fat cells from the flaps survived after 12 months of fat plantation, while those in control groups disappeared after 6 months.

CONCLUSIONSThe survival rate and duration of grafted fat could be increased implanting the fat tissues from delayed fat flap, which may provide researchers with a new method for fat graft.