Preclinical Study of Radiation on Fat Flap Regeneration under Tissue-engineering Chamber: Potential Consequences for Breast Reconstruction.

Abstract

Twenty-eight female Wistar rats were distributed into three groups: TEC implantation as nonirradiated controls (G1), TEC insertion followed by irradiation 3 weeks later (G2), and irradiation 6 weeks before TEC insertion (G3). G2 and G3 received 33.3 Gy in nine sessions of 3.7 Gy. Growth of the fat flap was monitored via magnetic resonance imaging. At 6 months after implantation, fat flaps and TECs were harvested for analysis. Irradiation did not alter the physicochemical features of poly(lactic-co-glycolic acid)-based TECs. Compared with G1, fat flap growth was significantly reduced by 1.6 times in irradiated G2 and G3 conditions. In G2 and G3, fat flaps consisted of mature viable adipocytes sustained by CD31+ vascular cells. However, 37% (3 of 8) of the G2 irradiated adipose tissues presented a disorganized architecture invaded by connective tissues with inflammatory CD68 + cells, and the presence of fibrosis was observed. Overall, this preclinical study does not reveal any major obstacle to the use of TEC in a radiotherapy context. Although irradiation reduces the growth of fat flap under the TEC by reducing adipogenesis and inducing inconsistent fibrosis, it does not impact flap survival and vascularization. These elements must be taken into account if radiotherapy is proposed before or after TEC-based breast reconstruction.