Anti-adipogenic Effect and Mechanism in 3T3-L1 Preadipocyte Differentiation by Salvianolic Acid B

Abstract

Salvianolic acid B (Sal B) is one of the most active hydrophilic compounds extracted from Salvia miltiorrhiza root. Previous in vitro and in vivo studies demonstrate the ability of Sal B to modulate adipocyte differentiation. However, the lipid-modulating effect and mechanism of Sal B in adipocytes remain controversial. Here we investigated the regulatory effect and mode of action of Sal B on lipid accumulation in 3T3-L1 preadipocyte differentiation. Lipid droplet (LD) accumulation and triglyceride (TG) content during 3T3-L1 preadipocyte differentiation were measured by Oil Red O staining and AdipoRed assay. The growth inhibition during 3T3-L1 preadipocyte differentiation was measured by cell count analysis. Western blotting and real-time qPCR analysis were utilized to determine the protein and mRNA expression in the preadipocyte differentiation. Notably, in 3T3-L1 preadipocyte differentiation, treatment with Sal B at 100 μM led to a marked decrease in LD accumulation and TG content without influencing cell growth. Sal B treatment (100 μM) further reduced the expression and phosphorylation levels of adipogenic transcription factors, including CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-gamma (PPAR)-γ, and signal transducer and activator of transcription (STAT)-3/5. Treatment with Sal B (100 μM) also reduced the expression and phosphorylation levels of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC), two lipogenic enzymes and perilipin A, an LD-binding and stabilizing protein. These results collectively demonstrate that Sal B at 100 μM strongly inhibits lipid accumulation in 3T3-L1 preadipocyte differentiation, mediated through regulation of the expression and phosphorylation levels of C/EBP-α, PPAR-γ, STAT-3/5, FAS, ACC, and perilipin.