RESUMO
Objective:To investigate the effects of sodium arsenite (NaAsO 2) on the expression of sterol regulatory element-binding protein-1c (SREBP-1c), peroxisome proliferator activated receptor α (PPARα) and fatty acid synthase (FAS) in human liver cells (L-02 cells). Methods:L-02 cells were cultured in vitro, and exposed to NaAsO 2 at 0 (control), 2, 4, 8, 16, 32, 64 and 128 μmol/L for 24 h, respectively, and the cell survival rate was determined by CCK-8 method. And a fitting curve was made to calculate the half inhibitory concentration (IC 50), subsequent experiments were carried out with 0, 1/8, 1/4 and 1/2 of IC 50 as arsenic exposure doses. Glycerol phosphate oxidase-catalase (GPO-PAP) method was used to detect the content of triglyceride (TG) in cells; the mRNA expression levels of SREBP-1c, PPARα and FAS were detected by Real-time PCR; and the protein expression levels of SREBP-1c and PPARα were detected by Western blotting. Results:The cell survival rates of 8, 16, 32, 64 and 128 μmol/L NaAsO 2 groups [(92.000 ± 1.414)%, (91.000 ± 0.000)%, (76.500 ± 0.707)%, (53.000 ± 1.412)%, (47.000 ± 1.412)%] were significantly lower than that of the control group [(100.000 ± 0.000)%, P < 0.01]. The IC 50 was 64 μmol/L, and subsequent experiments were conducted with 0 (control), 8, 16 and 32 μmol/L NaAsO 2, respectively. Compared with the control group [(1.000 ± 0.000) mmol/g prot], TG contents of 8, 16 and 32 μmol/L NaAsO 2 groups [(0.691 ± 0.064), (0.474 ± 0.162), (0.184 ± 0.045) mmol/g prot] were significant decreased ( P < 0.01). Compared with the control group, the mRNA expression levels of SREBP-1c, PPARα, FAS, and the protein expression levels of SREBP-1c and PPARα in NaAsO 2 groups were significantly decreased ( P < 0.01 or < 0.05). Correlation analysis showed that NaAsO 2 content was negatively correlated with TG content, SREBP-1c and PPARα protein expression levels ( r =-0.954,- 0.875,-0.965, P < 0.01). Conclusion:NaAsO 2 can reduce the TG content and the expression of lipid metabolism related genes SREBP-1c, PPARα and FAS in L-02 cells, suggesting that arsenic-induced liver injury can cause lipid metabolism disorders.
RESUMO
Objective To investigate the effects of three mitogen-activated protein kinase (MAPK) inhibitors on the expressions of transforming growth factor-β1 (TGF-β1),α-smooth actin (α-SMA) mRNA and protein in human liver stellate cells (LX-2 cells) activated by sodium arsenite.Methods Cultured in vitro LX-2 cells in the logarithmic growth stage were exposed to sodium arsenite at 0.0 (control),2.5,5.0,10.0,20.0,40.0,80.0 μmol/L for 24 h,respectively,and the cell survival rate was determined by CCK-8 assay.According to the results of the study,LX-2 cells were divided into 5 groups:control group,sodium arsenite group,extracellular signal regulation kinase (ERK) inhibition group,c-Jun amino-terminal kinase (JNK) inhibition group,and p38 inhibition group.LX-2 cells were pre-treated with 10.0 μmol/L ERK,JNK,p38 kinase inhibitors (PD98059,SP600125,SB203580) for 30 min in the 3 inhibition groups,and then 20.0 μmol/L sodium arsenite for 24 h.The control group was not treated with sodium arsenite and inhibitors.Sodium arsenite group was not treated with inhibitors.Then mRNA and protein expression levels of TGF-β1 and α-SMA in LX-2 cells were determined by Western blotting and real-time PCR,respectively.Results The survival rates of LX-2 cells in 5.0,10.0,20.0,40.0,80.0 μmol/L sodium arsenite groups were [(92.35 ± 0.92)％,(84.06 ± 0.84)％,(74.27 ± 0.74)％,(59.57 ± 0.60)％,(27.77 ± 0.23)％],which were significantly lower than that of the control group [(100.00 ± 0.00)％,P ＜ 0.05].It was found that the expressions of TGF-β1,o-SMA mRNA and protein of sodium arsenite group were higher than those of the control group (P ＜ 0.01).The expressions of TGF-β1,α-SMA mRNA and protein of the three inhibition groups were lower than those of the sodium arsenite group (P ＜ 0.05).Conclusions Arsenic exposure can cause abnormally high expressions of TGF-β1,α-SMA mRNA and protein in LX-2 cells.Intervention with three MAPK inhibitors can improve the effects of arsenic induced LX-2 cells activation on the expressions of TGF-β1,α-SMA mRNA and protein.