Abstract: Objective To optimize the methods of the induction and differentiation of 3T3-L1 preadipocytes. Methods Based on the "cocktail" method, 3T3-L1 preadipocytes were divided into four groups according to the differentiation medium A:(1) Control group; (2) Ros:rosiglitazone group; (3) Indo:rosiglitazone group; (4) Ros+Indo:rosiglitazone+indometacin combination group. During the differentiation, cell morphology was observed through microscope. Oil red O was stained and quantified. The intracellular and extracellular triglyceride (TG) content was measured via TG GPO-PAP enzymatic kit. Results The differentiation rates were higher in group "Ros", "Indo" and "Ros+Indo", with earlier adipogenesis and more lipid droplets, which was further demonstrated in oil red O staining. In the evaluation of one simple lipid droplet with three parameters:mean diameter, mean area and max diameter, the droplet in group "Ros", "Indo" and "Ros+Indo" were much bigger than that in control group, while there was no statistically significance between control and "Indo" group. Regarding TG content, there was no significant difference among four groups in extracellular TG, but intracellular TG was higher in "Ros+Indo" group than that in control group (0.77±0.07 mmol/g vs 0.19±0.02 mmol/g, P<0.05). Conclusion Based on the classical "cocktail" method, PPAR-γ agonist rosiglitazone significantly improves the differentiation rate of 3T3-L1 preadipocytes.

Key words: preadipocyte, 3T3-L1, differentiation