Salvianolic Acid B Reduces the Inflammation of Fat Grafts by Inhibiting the NF-Kb Signalling Pathway in Macrophages

Background Autologous fat grafting is a common method for soft tissue defect repair. However, the high absorption rate of transplanted fat is currently a bottleneck in the process. Excessive inflammation is one of the main reasons for poor fat transplantation. Salvianolic acid B (Sal-B) is an herbal medicine that can be used to improve the effectiveness of fat transplantation. This article will explore the role of Sal-B in the inflammatory response to fat transplantation and its related mechanisms. Objective Aiming to improve fat graft survival by injecting Sal-B into fat grafts locally. Methods In vivo, 0.2 ml of Coleman fat was transplanted into nude mice along with Sal-B. The grafts were evaluated by histological analysis at 2-, 4- and 12-weeks post-transplantation and by micro-computed tomography (CT) at 4 weeks post-transplantation. In vitro, ribonucleic acid sequencing (RNA-Seq), cell proliferation assays, anti-inflammatory activity assays, molecular docking studies and kinase activity assays were performed in RAW264.7 cells to detect the potential mechanism. Results Sal-B significantly improved fat graft survival and attenuated adipose tissue fibrosis and inflammation. Sal-B also inhibited the polarization of M1 macrophages in fat grafts. In vitro, Sal-B inhibited the proliferation and activation of inflammatory pathways in RAW264.7 cells. In addition, Sal-B had an inhibitory effect on nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-κB) signalling. This bioactivity of Sal-B may result from its selective binding to the kinase domain of inhibitor of nuclear factor kappa B kinase subunit beta (IKK-β). Conclusions Sal-B could serve as a promising agent for improving the effect of fat transplantation by inhibiting the polarization of M1 macrophages through NF-κB signalling.