RÉSUMÉ
@#Objective - ( ) To investigate the effects of nuclear factor erythroid 2 related factor 2 NRF2 on the oxidative stress ( ) Methods ) ,, induced by trichloromethane TCM in human normal hepatocyte L02 cells. i L02 cells were stimulated with 1 2 , , , ( ), 4 8 12 16 and 20 mmol/L TCM solution dissolved in dimethyl sulfoxide and the control group and blank group were set , - , up. After culturing for 24 hours the cell viability was detected by CCK 8 colorimetric method and the concentration of TCM ) -, - stimulation was screened. ii L02 cells in logarithmic growth phase were randomly divided into control group and low medium - , , , and high dose groups. After 24 hours of exposure to 0 4 8 and 12 mmol/L TCM the cells were collected. The activity of ( ), ( ), ( - ) ( ) superoxide dismutase SOD catalase CAT glutathione peroxidase GSH Px and the level of malondialdehyde MDA NRF2, - (HO-1), were detected by colorimetric analysis. The mRNA expression levels of heme oxygenase 1 glutamate cysteine (GCLC) () (NQO1) - ligase catalytic subunit and NAD P H quinone dehydrogenase 1 were detected by real time fluorescence , - , polymerase chain reaction. The protein levels of NRF2 HO 1 GCLC and NQO1 were detected by Western blotting.Results ) , , , , i When the concentration of TCM was 4 8 12 16 and 20 mmol/L the survival rate of L02 cells decreased ( P ) , , significantly compared with the control group all <0.05 . The concentration of 0 4 8 and 12 mmol/L were selected as the ) , - stimulation doses for subsequent experiments. ii Compared with the control group the activities of SOD and GSH Px in L02 ( P ) ( P ), - cells in the three doses groups decreased all <0.05 and the levels of MAD increased all <0.05 with a dose effect - (P ), relationship. The CAT activity of L02 cells in the medium dose group was lower than that in the control group <0.05 and the - ( P ) CAT activity of L02 cells in the high dose group was lower than that in the others three groups all <0.05 . Compared with the , NRF2 - (P ),NRF2 control group the relative expression levels of mRNA in L02 cells in the low dose group decreased <0.05 - (P ), NRF2 mRNA in L02 cells in the medium dose group increased <0.05 mRNA and NRF2 protein expression in L02 cells in ( P ) HO-1,GCLC, NQO1 , the highdose group increased both <0.05 . The relative expression level of mRNA and GCLC NQO1 ( P ) protein expression in L02 cells in the three doses groups increased compared with the control group all <0.05 . The relative NRF2 - - - expression level of mRNA in L02 cells in the high dose group was higher than that in the low and medium dose groups ( P ), - (P ), both <0.05 and the relative expression of NRF2 protein was higher than that in the low dose group <0.05 but the HO-1 GCLC - - ( relative expression levels of and mRNA and HO 1 protein level were lower than those in the medium dose group all P )Conclusion - <0.05 . TCM exposure can inhibit the proliferation of L02 cells by inducing oxidative stress with a dose effect , relationship. In this process the antioxidant mechanism mediated by NRF2 was activated. The expression of antioxidant defense , - , and detoxification related target genes downstream of NRF2 signaling pathway was activated and the expression of HO 1 - GCLC and NQO1 was up regulated to alleviate the oxidative damage caused by TCM.