Long-term monitoring of adipogenesis and lipid droplet accumulation of preadipocyte using electrical impedance measurement

Abstract

It has been considered that obesity and metabolic syndrome would be caused by the accumulation of lipid droplets in adipocytes, and would cause a severe problems. To treat these diseases, functional foods to suppress the lipid accumulation are being actively developed, and manufactures are required to approve the efficacy of these foods. However, the quantitative and accurate evaluation methodology of efficacy has not been established yet. Since lipids have a high electrical impedance, it is considered that the amount of lipid droplets in adipocytes is related to the electrical impedance. Therefore, culturing adipocytes and monitoring their electrical impedance simultaneously would enable to evaluate the amount of lipid droplets, and to establish the screening system for functional foods. In this study, mouse preadipocytes (3T3-L1) were cultured on comb-shaped indium-tin oxide (ITO) electrodes to measure the electrical impedance. Moreover, the relationship between the electrical impedance, adipogenesis, and lipid accumulation was evaluated. Briefly, the 3T3-L1 cells were cultured with and without adipogenesis factors for 288 hours. Complex impedance Z and phase angle θ of the cultured cells were monitored during the culture time. As the results, the cell viability was maintained on the ITO electrode-array surface. The complex impedance Z of cells cultured under adipogenesis condition increased during the adipogenesis process. During the lipid accumulation process, phase angle θ tended to increase. These results indicated that the change in impedance Z and phase angle θ could be related to adipogenesis and lipid accumulation respectively. In conclusion, our novel culturing and monitoring device for preadipocytes showed the possibility to evaluate the efficacy of functional foods.

Keywords

• 3t3-l1
• preadipocyte
• adipogenesis
• lipid droplet
• electrical impedance