Abstract: Objective To construct a novel core-shell-structured chitosan particles with sustained-release FGF2 plasmids (the core was pFGF2-EGFP-loaded TACS and the shell was HBC), and to explore the effect of the particles on the survival rate of adipose tissue transplantation. Methods The core-structured particles (TACS-pFGF2-EGFP) and core-shell-structured particles (HBC@TACS-pFGF2-EGFP) were prepared to explore the release regulation of pFGF2-EGFP of these particles. The expression of FGF2 protein was detected by Western Blot after in vitro transfection of 293T cells. Eighteen New Zealand white rabbits were used for adipose tissue transplantation experiment. The left ears were treated as experimental group and the right ears were treated as control group. The ears in experimental group were implanted with 2 mL fat particles and HBC@TACS-pFGF2 particles while the ears in control group were implanted with 2 mL fat particles and HBC@TACS-empty plasmids. The new adipose tissues were harvested to analyze the survival rate at 4, 8, 12 weeks after transplantation. Besides, the biological characteristics of grafts and the density of new blood vessels were observed at the same time by HE staining and immunohistochemistry. Results The FGF2 protein can be slowly released by HBC@TACS-pFGF2 particles in vitro and be successfully expressed after transfection of 293T cells. At different time point, new fat tissues were observed. The volume of adipose tissues were gradually reduced after transplantation. The survival rates of adipose tissues in the experimental group were significant higher than in control group at any time point (P<0.05). HE staining showed the new fat cells arranged more regularly in experimental group than the cells in control group. Immunohistochemistry staining showed the density of new blood vessels in adipose tissue in experimental group was higher than that in control group (P<0.05). Conclusion HBC@TACS-pFGF2-EGFP particles can improve the survival rate of fat transplantation.

Key words: Gene therapy, Adipose tissue transplantation, Basic fibroblast growth factor