Lipolysis inhibition improves the survival of fat grafts through ameliorating lipotoxicity and inflammation

Abstract

Fat grafting is a promising technique for correcting soft tissue abnormalities, but oil cyst formation and graft fibrosis frequently impede the therapeutic benefit of fat grafting. The lipolysis of released oil droplets after grafting may make the inflammation and fibrosis in the grafts worse; therefore, by regulating adipose triglyceride lipase (ATGL) via Atglistatin (ATG) and Forskolin (FSK), we investigated the impact of lipolysis on fat grafts in this study. After being removed from the mice and chopped into small pieces, the subcutaneous fat from wild‐type C57BL/6J mice was placed in three different solutions for two hours: serum‐free cell culture medium, culture medium+FSK (50 μM), and culture medium+ATG (100 μM). Following centrifugation to remove water and free oil droplets, 0.3 mL of the fat particles per mouse was subcutaneously injected into the back of mice. Additionally, the subcutaneous fat grafting area was immediately injected with PBS (control group), ATG (30 mg/kg), and FSK (15 mg/kg) following fat transplantation. Detailed cellular events after grafting were investigated by histological staining, real‐time polymerase chain reaction, immunohistochemistry/immunofluorescent staining, and quantification. Two weeks after grafting, grafts treated with ATG showed lower expression of ATGL and decreased mRNA levels of TNFα and IL‐6. In contrast, grafts treated with ATG showed elevated expression levels of IL‐4 and IL‐13 compared to the control grafts. In addition, fewer apoptotic cells and oil cysts were observed in ATG grafts. Meanwhile, a higher CD206+/CD68+ ratio of macrophages and more CD31+ vascular endothelial cells existed in the 2‐month ATG grafts. In comparison to the control, ATG treatment improved the volume retention of grafts, and decreased graft fibrosis and oil cyst formation. By preventing oil droplet lipolysis, pharmacological suppression of ATGL shielded adipocytes from lipotoxicity following grafting. Additionally, ATG ameliorated the apoptosis and inflammation brought on by adipocyte death and oil droplet lipolysis in grafted fat. These all indicate that lipolysis inhibition improved transplanted fat survival and decreased the development of oil cysts and graft fibrosis, offering a potential postoperative pharmacological intervention for bettering fat grafting.