Effects of Ghrelin on the Proliferation and Differentiation of 3T3-L1 Preadipocytes / 华中科技大学学报（医学）（英德文版）

ABSTRACT

The effects of ghrelin on the proliferation and differentiation of 3T3-L1 preadipocytes and the possible mechanisms were investigated in this study.3T3-L1 preadipocytes were cultured in vitro and treated with different concentrations of ghrelin.Proliferation of 3T3-L1 preadipocytes was evaluated by MTT method and mRNA levels of c-myc and thymidine kinase were detected by RT-PCR.Morphological changes of 3T3-L1 preadipocytes were observed and cell differentiation was measured by oil red O staining.The mRNA levels of peroxisome proliferator-activated receptor γ (PPARγ) and CAAT/enhancer binding protein (C/EBPα) in the cells at different differentiation stages were detected by RT-PCR.The results showed that ghrelin at concentrations of 10-7 to 10-15 mol/L could significantly promote preadipocyte proliferation (P<0.05),with the most pronounced effect observed at 1011mol/L (P<0.01).Treatment of 3T3-L1 preadipocytes with ghrelin significantly in-creased the mRNA levels of c-myc and thymidine kinase (P<0.01).Morphological findings demonstrated that the great amount of lipid droplets appeared in the 3T3-L1 preadipocytes treated with ghrelin.Ghrelin could morphologically induce the differentiation of 3T3-L1 preadipocytes into mature adipocytes.Ghrelin significantly increased the mRNA levels of PPART and C/EBPα during the differentiation,when compared with control group (P<0.05).The mRNA levels of PPARγ and C/EBPα were obviously up-regulated with the differentiation of preadipocytes after the treatment of ghrelin.There were significant difference in the mRNA levels of PPARγ and C/EBPα on day 2 and day 8 of the differentiation of 3T3-L1 preadipocytes (P<0.01).In conclusion,ghrelin could promote the proliferation and differentiation of 3T3-L1 preadipocytes by increasing the mRNA levels of PPARγ and C/EBPα and therefore enhance the sensitivity of adipocytes against insulin.