BACKGROUND:Preadipocyte is a kind of specific precursor cells with the potential of proliferation and differentiation into adipocytes.If factor or drug with strong promotion of preadipocyte proliferation and differentiation is obtained and used in adipose tissue transplantation,which could elevate transplantation outcome of adipose tissues.OBJECTIVE:To find an optimal culture environment and to accumulate culture experience of in vitro culture 3T3-L1 preadipocytes,and to observe the effect of insulin-like growth factor(IGF)-1 on the proliferation and differentiation of 3T3-L1 preadipocytes,and to explore the optimal concentration of IGF-1.DESIGN,TIME AND SETTING:The cell control observation was performed at the Science Experiment Center,Liaoning University of Traditional Chinese Medicine from October 2007 to February 2008.MATERIALS:3T3-L1 preadipocytes were purchased from Shanghai Institutes For Biological Sciences.IGF-1 was bought from Biological,USA.METHODS:According to in vitro culture direction of 3T3-L1 preadipocytes,3T3-L1 preadipocytes were divided into 6 groups.3T3-L1 preadipocytes in the blank control group were inoculated in high-glucose DMEM supplemented with 0.1 volume fraction of fetal bovine serum.3T3-L1 preadipocytes in each experimental groups were respectively treated with high-glucose DMEM containing 5,10,20,50,100 ?g/L IGF-1 and 0.1 volume fraction of fetal bovine serum.MAIN OUTCOME MEASURES:Growth,proliferation and differentiation of 3T3-L1 preadipocytes in each experimental groups under the inverted microscope,and photographed.When cells were confluence,cell cycles were detected by flow cytometry.Growth rate of 3T3-L1 preadipocytes was measured by MTT essay.Fat growth rate in 3T3-L1 preadipocytes were examined by using oil red O stained-extracted assay.RESULTS:Inverted microscope showed that 3T3-L1 preadipocytes before differentiation were fusiform shape,with little fat in their endochylemas.3T3-L1 preadipocytes after differentiation were spherical shape,with much fat in their endochylemas.Lipid droplet gathered in the perinuclear space,and was stained orange by oil red O stained-extracted assay,forming ring-shape.Results from MTT essay and oil red O stained-extracted assay demonstrated that growth rate of 3T3-L1 preadipocytes and fat growth rate in 3T3-L1 preadipocytes were higher in each experimental groups treated with different doses of IGF-1 compared with the blank control group(P