Oral administration of megestrol acetate can increase fat graft survival in a rat model

Insufficient and inconsistent survival is a significant shortcoming of fat grafts. Reportedly, megestrol acetate (MA) could induce proliferation, migration, and adipogenic differentiation of adipose-derived stem cells in vitro. Thus, we tested whether MA could promote fat graft survival in a rat model. Twenty-eight Sprague-Dawley rats (8 weeks old, male) were divided into two groups: experimental (MA group, n = 14) and control (n = 14). The inguinal fat pad (1 g) was extracted en bloc and re-implanted under the scalp in both groups. MA (100 mg/kg/day) was administered orally for 14 postoperative days in the experimental group. After 6 weeks, the volume and weight of the grafted fat were measured. Histologic examination with hematoxylin and eosin (HE) and real-time polymerase chain reaction (PCR) for vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), and CCAAT/enhancer-binding protein alpha (C/EBP-α) were performed. Perilipin staining was performed to check the viability of grafted fat. Graft fat volume was greater in the MA group, compared with that in the control (P = 0.023). The MA group also had more viable cells, including more adipocytes, and less fibrosis or vacuoles than the control on HE and perilipin staining. MA upregulated the expression of FGF2 (P<0.001), VEGF (P = 0.008), and C/EBP-α (P = 0.002) at the second postoperative week. MA increased survival of grafted fat in an animal model. Increased vascularization and adipogenesis were related to these results. Further human clinical trials are necessary to evaluate adjunctive oral administration of MA after fat grafting to promote graft survival.