RESUMO
BACKGROUND: The adjunction of platelet-rich plasma with graft fat has been the subject of a few clinical trials which have demonstrated its value in adipocyte survival. The aim of this study was to assess the different efficacies between activated and non-activated PRP on adipose cells in vitro and for adipose tissue graft survival in vivo. METHODS: The in vitro study assessed the effects of PRP on both the proliferation and adipocyte differentiation of adipose cells. For the in vivo study, 8 nude rats received 3 human fat injections as follows: 0.8 mL of fat + 0.2 mL of normal saline; 0.8 mL of fat + 0.2 mL of non-activated PRP; and 0.8 mL of fat + 0.2 mL of PRP activated with calcium chloride (CaCl2). The quantitative assessment of adipocyte survival was implemented after 3 months using histomorphometric analysis. Histological and immunohistochemical analysis were also performed to evaluate angiogenesis, inflammation and quality of adipocytes in the grafted tissue. RESULTS: We showed that activated PRP stimulated, in vitro, proliferation and differentiation of adipose cells. In vivo experiments indicated that CaCl2-activated PRP was more efficient than non-activated to prolong the survival of fat grafts in nude rats. The mean percentage areas occupied by viable adipocytes in the PRP-free group, non-activated PRP group and activated PRP group were 13%, 14% and 24% (p = 0.05%), respectively. Histological and immunohistochemical analysis revealed protective effect of activated PRP on inflammation and adipocyte death. CONCLUSION: This study showed that activation by CaCl2 improves the beneficial effects of PRP for fat graft maintenance.