RESUMO
Objective To investigate the changes of growth arrest and DNA damage inducible gene ?(GADD45?)expression during 3T3-L1 preadipocyte differentiation and analyze the regulative role of tumor necrosis factor-alpha(TNF-?) on GADD45? gene expression in matured 3T3-L1 adipocytes.Methods 3T3-L1 preadipocytes were cultured in vitro and differentiated into the matured adipocytes.TNF-? in different concentrations(0.1,1.0,10.0 ?g/L) was added into the culture medium of fully differentiated adipocytes(day 10) for various times(0.5,2,6,12,24 h).The levels of GADD45? gene mRNA expression were evaluated by reverse transcription polymerase chain reaction(RT-PCR).Results With the 3T3-L1 preadipocytes being differentiated into the matured adipocytes,the level of GADD45? gene mRNA expression was downregulated and reached the lower level in fully differentiated adipocytes.There was a significant difference between any 2 detected phases in the levels of GADD45? gene mRNA expression(P0.05).Treatment of day 10(3T3-L1) adipocytes with TNF-? of different concentrations resulted in a significant increase in the level of GADD45? gene mRNA expression.The induction effect of TNF? on GADD45? gene mRNA expression generally tended to be reinforced with the elongation of time course.Conclusions GADD45? gene may be involved in adipocyte differentiation and adipogenesis.TNF-? can upregulate the mRNA expression of GADD45? gene in matured adipocytes.The induction effect of TNF-? on GADD45? gene expression is generally(time-)correlated.