Abstract:

Objective: To investigate the potential effects and underlying mechanisms of isoliquiritigenin on the
differentiation of 3T3-L1 preadipocytes. Methods: The SRB assay was used to evaluate the effects of isoliquiritigenin on the
proliferation of 3T3-L1 preadipocytes. The differentiation of 3T3-L1 cells was induced by cocktail reagents. The formation
of lipid droplets in the differentiated adipocytes was observed after oil red O staining and quantified by colorimetry. The
expression of CCAAT-enhancer-binding proteins (C/EBP)-α and-β, fatty acid synthetase (FAS), adipophilin, peroxisome
proliferators activated receptor γ (PPARγ) and adenosine monophosphate activated protein kinase (AMPK) genes was
measured by quantity real-time reverse transcript polymerase chain reaction (qRT-PCR). The phosphorylation of AMPK
protein was detected by Western blotting. Results: Isoliquiritigenin inhibited the proliferation of 3T3-L1 preadipocytes in
a concentration-dependent manner. The isoliquiritigenin treatment significantly decreased the formation of lipid droplets
in differentiated adipocytes. Furthermore, isoliquiritigenin down-regulated the mRNA expression of C/EBPα, C/EBPβ,
FAS, adipophilin, and PPARγ genes. On the other hand, isoliquiritigenin had no obvious effects on the mRNA expression of
AMPK gene, but up-regulated the phosphorylation of AMPK. Conclusion: Isoliquiritigenin could inhibit the proliferation
and differentiation of 3T3-L1 preadipocytes due to the activation of AMPK signal pathway.

Key words: isoliquiritigenin, 3T3-L1 preadipocytes, differentiation, lipogenesis, adenosine monophosphate activated protein kinase (AMPK)