[Mitochondrial dysfunctions of keloid fibroblasts and it' s effects on cell metabolic functions]

To compare the differences of mitochondrial functions between keloid fibroblasts and normal skin fibroblasts and explore its relationship with cell proliferation.

Keloid fibroblasts (KFb) and normal skin fibroblasts (NFb) were isolated by explants culture method. KFb and NFb were cultured under normoxia or hypoxia (2％ O2).Differences of cell proliferation were detected by CCK-8.Flow cytometer was used to detect the content of mitochondria and reactive oxygen species (ROS) in KFb and NFb. Ultra-structures of mitochondria in KFb and NFb were observed by transmission electron microscope (TEM).Mitochondria fusion/fission related genes MFN1,MFN2 and FIS1 were detected by RT-PCR. Oxygen consumption rate, lactate production and ATP contents were determined by spectrophotometry.

KFb showed a higher proliferation rate compared with NFb, especially under hypoxia. The oxygen consumption rate, ATP content, lactate production and ROS of KFb were lower than NFb under normoxia. After incubated under hypoxia, there was a significant increase in oxygen consumption, ATP content, lactate production and ROS in KFb, while NFb showed less increase compared with KFb. KFb had 15.33％ more mitochondrion than NFb, and expressions of MFN1, MFN2, FIS1 in KFb were 33.27％,113.39％ and 20.34％ higher compared with NFb. Under TEM, KFb showed an increase of enlarged mitochondrion, with disrupted inner membrane and loss of cristae.

KFb may have dysfunctions of mitochondrion which lead to changes of cell metabolism and continuous proliferation of KFb.