ABSTRACT
OBJECTIVE: To study the effect of curcumin on the oxidative stress induced by nano-silicon dioxide( SiO_2) in A549 cells and to explore its potential mechanism. METHODS: A549 cells were randomly divided into 6 groups. Nano-SiO_2 group cells were stimulated with nano-SiO_2 solution with a final concentration of 20 mg/L; curcumin low-,medium-,and high-dose group cells were treated with curcumin at final concentrations of 5,10,and 20 μmol/L respectively and 20 mg/L nano-SiO_2 solution; the solvent control group was treated with dimethyl sulfoxide with a volume fraction of 0. 10%. The cells in the blank control group were not given any treatment. The cells in these 6 groups were incubated for 12 hours,and the level of malondialdehyde( MDA) and the activity of total superoxide dismutase( T-SOD) in the cells were measured by spectrophotometer. The relative expression of mRNA and protein of nuclear factor E2-associated factor 2( NRF2),thioredoxin-1( TRX1),and thioredoxin interaction protein( TXNIP) were analyzed by real-time fluorescent quantitative polymerase chain reaction and Western blot respectively. RESULTS: The MDA level in A549 cells of nano-SiO_2 group increased( P < 0. 05),the T-SOD activity decreased( P < 0. 05),and the mRNA and protein relative expression of NRF2 and TRX1 were up-regulated( P < 0. 05),TXNIP relative expression of mRNA and protein were down-regulated( P <0. 05),when compared with the blank control group and the solvent control group. After intervention with curcumin,with the increased of curcumin concentration,the MDA level in A549 cells decreased,the T-SOD activity increased,the relative expression of NRF2 mRNA and TRX1 mRNA and protein was up-regulated,the mRNA and protein relative expression of TXNIP was down-regulated,and showed a dose-dependent manner( P < 0. 01). CONCLUSION: Curcumin can protect nano-SiO_2-induced oxidative stress in A549 cells. It may activate TRX system by regulating NRF2/antioxidant response elements pathway,exerting an anti-oxidation effect and protecting cells from excessive oxidative damage.
ABSTRACT
Objective To investigate the toxic effect of nona-ferroso-ferric oxide(Nano-Fe_3O_4),nano-silicon dioxide(Nano- SiO_2)and single walled carbon nanotubes(SWCNTs)on the lung and mechanism in rats.Methods Fourty-nine Wistar rats were randomly divided into 7 groups,the control group,low and high dose groups of three nanomaterials.The rats were exposed by intratracheal instillation once two days for 5 weeks,and then killed by abdominal aorta bloodletting.The pathology of lung,lactate dehydrogenase(LDH),total antioxidant capacity(T-AOC),superoxide dismutase(SOD),malondialdehyde(MDA),interleukin-1(IL- l),interleukin-6(IL-6)and tumor necrosis factor-?(TNF-?)in bronchoalveolar lavage fluid(BALF)were determined.Results The fibrous tubercle and the matrix inflammation of lung tissue was found in the experimental groups.The activities of T-AOC and SOD decreased while IL-6 concentration increased significantly in the experimental groups(P
ABSTRACT
Objective To study the oxidative damage on testis of male rats induced by micro-nano-scale SiO2. Methods Male Wistar rats were exposed to nanometer SiO2(20-40 nm) and micro-meter SiO2(1-10 ?m)by intratracheal injection once two days. The rats were killed after 5 weeks of exposure. Some indicators related to the oxidative damage in the serum and the testis were determined. Results The activity of GSH-Px and SOD in the high dose groups decreased significantly and the MDA levels increased compared to the control group;The MDA levels of nano-silicon dioxide high dose group increased in the serum. Conclusion Nano-silicon dioxide may cause lipid peroxidation in the testis with a tendency of higher toxicity than that of micro-SiO2 at the same exposed level,the detail mechanism needs further discussion.