The Effect Of Curcumin On Oxidative Damage Induced By Nano-silica In A549 Cells

Objective To explore the influence and the possible mechanisms of curcumin on oxidative stress damage in the A549 cells stimulated by nano-silicon dioxide throungh the changes in the expression of Nuclear factor erythroid-2 p45-related factor2（Nrf）,Thioredoxin 1（Trx1）and Thioredoxin interacting protein（TXNIP）genes and proteins,and the changes of Total super oxide dismutase（T-SOD）,Malondialdehyde（MDA）and Glutathione（GSH）levels in different groups of cells.Methods Firstly,A549 cells were stimulated with different concentrations of nano-SiO₂for 12 h.The morphological changes of cells in each group were observed under a light microscope.The viability of each group of cells was detected by CCK-8 kit and the appropriate concentration of nano-SiO₂ was selected for subsequent experiments.The oxidative stress model was established by treating the A549 cells with the appropriate concentration of nano-SiO₂ for 12 hours.The experiments were divided into normal control group,solvent control group,nano-SiO₂ group and curcumin low,middle and high dose groups.Except for the normal control group,A549 cells were cultured for 12 hours in the medium containing different treatment components;T-SOD,MDA,and GSH kits were used to detect changes in oxidative stress and oxidative damage in the cells.The effect of curcumin on the oxidative damage of A549 cells induced by nano-SiO₂ was inferred;the mRNA and protein expression of Nrf2,Trx1 and TXNIP in cells of different treatment groups were detected by real-time fluorescence quantitative PCR and Western Blot,and the genes and proteins were analyzed.To investigate the possible mechanism of curcumin-induced oxidative damage on A549 cells induced by nano-SiO2.Results 1 The normal cells adhered well to the light microscope and showed a spindle shape.With the increase of nano-SiO₂ stimulation concentration,the suspended cells in the medium increased in turn and the degree of cell shrinkage increased.The results of CCK-8showed that:A549 cells Activity decreased with the increasing concentration of nano-SiO₂stimulation;except for the 10μg/ml nano-SiO₂ group,the survival rate of cells did not change significantly（P>0.05）,and the survival rate of the other groups decreased statistically（P<0.05）.Need,follow-up experiment selected 20μg/ml nano-SiO₂ for the cell stimulation concentration is more appropriate.2 Results of oxidative stress-related indicators:Compared with the normal control group,A549 cells stimulated by nano-SiO₂,intracellular MDA content increased,T-SOD activity decreased,GSH content decreased,the difference was statistically significant（P<0.05）;Compared with the SiO₂ group,the intracellular MDA content and the T-SOD activity were increased after curcumin treatment with different concentrations.The changes of the two groups were statistically significant（P<0.05）in the curcumin medium and high dose groups,and the GSH content increased significantly（P<0.05）.3 Western Blot assay results:compared with the normal control group,the expression of Nrf2 and Trx1 protein in the nano-SiO₂ group increased,and the TXNIP protein expression decreased（P<0.05）;low,medium,and high doses of curcumin Compared with the normal control group,the solvent control group,and the nano-SiO₂group,the expression of Nrf2 protein in the cells increased to different degrees（P<0.05）.The expression of Trx1 protein increased with the increase of curcumin concentration in the medium and high dose groups of curcumin.The increase of protein expression was statistically significant（P<0.05）;the expression of TXNIP protein decreased with the increase of curcumin concentration（P<0.05）.4 The results of real-time fluorescence quantitative PCR showed that compared with the normal control group,the mRNA expression of Nrf2,Trx1 in the nano-SiO₂ group and the low,medium,and high dose curcumin groups increased,and the mRNA expression of TXNIP decreased significantly.The change was statistically significant（P<0.05）;Compared with nano-SiO₂ group,mRNA expression of Nrf2 and Trx1 showed an upward trend with the increase of curcumin concentration,and TXNIP mRNA expression showed a decreasing trend,but gene expression was high in curcumin medium and high dose group.The change was significant（P<0.05）.Conclusions 1 Nano-SiO₂ has cytotoxicity,which can cause oxidative stress damage to cells,leading to apoptosis and cytotoxicity in a concentration-dependent manner.2Curcumin can upregulate Nrf2/ARE signaling pathway,increase or decrease the expression of anti-oxidative stress-related genes and proteins,increase cellular oxidative stress,reduce oxidative damage of A549 cells caused by nano-SiO₂,and exert cytoprotection.Provide reference for respiratory disease caused by nano-SiO₂ for clinical prevention occupation or general population.