Abstract: Objective To observe the number,distribution,structure and function of mitochondria in cultured human dermal papilla cells (DPCs) under aggregative and non-aggregative conditions.Methods DPCs were separated from human hair follicles by two-step enzymatic digestion and cultured in DMEM medium.Mitochondrion-selective stain,laser scanning confocal microscopy and transmission electron microscopy were used to observe the number,distribution and structure of mitochondria.Mitochondria membrane potential (Δψ_m)was detected by 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocy-anine iodide (JC-1).Results DPCs grew well in the culture.Compared with the DPCs with non-aggregative behavior,those with aggregative behavior had more mitochondria,which were visible throughout the cytoplasm and concentrated near the rough endoplasmic reticulum,with irregular shape,well-developed cristae and higher membrane potentials.Conclusions The number,distribution,structure and function of mitochondria are different between the DPCs under aggregative condition and those under non-aggregative condition,which suggests there are differences in energy consumption,cell metabolism and protein synthesis between the two conditions of DPCs.

Key words: Hair follicle, Mitochondria, Membrane potentials, Aggregative behavior