[Different effects of simvastatin on keloid fibroblasts under hypoxia and TGF-β1 treatment].

Objective: To explore the effect of simvastatin on the proliferation, apoptosis and protein expressions of keloid fibroblasts under normoxia,hypoxia or TGF-β1 treatment.

Methods: Keloid fibroblasts (KFs) were isolated by explants culture method. KFs were treated with different concentrations of simvastatin under normoxia or hypoxia (2％ O2) for 24 h and 48 h. The effects of simvastatin on cell proliferation were detected by CCK-8.Flow cytometer was used to detect the apoptosis of KFs treated with 10 μ mol/L simvastatin for 24 h or 48 h under normoxia, hypoxia or 10 ng/ml TGF-β1 treatment. Then the expressions of keloid-related proteins were analyzed by Western Blot.

Results: It showed that simvastatin could inhibit the proliferation of KFs in a concentration-and time-dependent manner with the concentration range of 10-500 μ mol/L for 24 h and 0.1-500 μ mol/L for 48 h. This inhibitory effect could be significantly enhanced when cells were incubated under hypoxia for 48h with 10-500 μ mol/L simvastatin.10 μ mol/L simvastatin could not influence the apoptosis of KFs under normoxia or TGF-β1 treatment, neither incubated for 24 h nor 48 h.When incubated under hypoxia,10 μ mol/L simvastatin could significantly induce the apoptosis of KFs, with the rate of 155.6％ for 24 h and 478.8％ for 48 h, compared with no-drug control. There are no significant influences on the expression of type Ⅰ collagen, CTGF or TIMP-1 when KFs were treated with 10 μ mol/L simvastatin under normoxia for 48 h. When incubated with 10 ng/ml TGF-β1 together with 10 μmol/L simvastatin for 48 h, the expression of CTGF was significantly inhibited. KFs treated with 10 μ mol/L simvastatin under hypoxia for 48 h showed a significant decrease of type Ⅰ collagen and CTGF, and a significant increase of TIMP-1.

Conclusions: Simvastatin has different effects on the proliferation, apoptosis and protein expressions of KFs in a dosedependent manner under different conditions. The effects are enhanced under hypoxia.