Suppressive Effects of Carotenoids on Proliferation and Differentiation of 3T3-L1 Preadipocytes

Abstract

Obesity results from excessive growth and expansion of adipose tissue due to preadipocyte proliferation and differentiation as well as excess lipid accumulation. The aim of the study was to assess the effects of bixin, lycopene, and β-carotene on proliferation and differentiation of 3T3-L1 preadipocytes. The cell viability was determined by MTT assays and their differentiation was evaluated by Oil red O staining and monitoring the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and fatty acid binding protein 4 (FABP4). The expression levels of leptin and acetyl-CoA carboxylase (ACC) were measured by West blots. The results showed that bixin, β-carotene and lycopene reduced the viability of 3T3-L1 preadipocytes and inhibited intracellular lipid accumulation. β-Carotene had stronger suppressive effects on lipid accumulation than bixin and lycopene. Treatments of these carotenoids obviously reduced expression levels of PPARγ and FABP4 proteins in 3T3-L1 cells. The carotenoids down-regulated leptin expression, but up-regulated ACC expression during adipocyte differentiation. Bixin, lycopene and β-carotene suppressed differentiation of 3T3-L1 preadipocytes through down-regulating protein expressions of PPARγ and FABP4 as well as leptin.