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Objective To investigate the adverse effects of nano-titanium dioxide (TiO2 )on kidney tissues in healthy rats and rats with oxidative stress (OS).Methods Thirty-six healthy male SD rats were randomly divided into control group, alloxan-treated group, nano-TiO2 treated (NM) group, and alloxan and nano-TiO2 dual treatment (OS-NM)group.Nano-TiO2 of three concentrations (0.5,5 and 50 mg/kg body weight)was injected intraperitoneally.The level of OS biochemical factors and blood urea nitrogen (BUN)and pathological changes of kidney were determined.Results Compared with those in NM and OS groups,the levels of O2 -· and superoxide dismutase (SOD)in OS-NM group were significantly increased after exposure to nano-TiO2 of 5 mg/kg body weight (P <0.05).Nano-TiO2 of 50 mg/kg body weight led to significant changes of O2 -·,SOD,and glutathione (GSH) levels in OS-NM group in comparison with OS and NM groups (P <0.01).The levels of O2 -· and GSH between OS group and NM group changed significantly (P < 0.05 ).Compared with healthy rats,OS rats showed significant increased BUN level (P <0.01),cell number and edema of renal tubular epithelial cells after nano-TiO2 exposure.A synergic effect between OS condition and nano-TiO2 level was shown on the increased level of O2 -·.Conclusion Nano-TiO2 induced more adverse effects on the kidney in OS rats,suggesting a synergistic effect between nano-TiO2 and OS.This result provides experimental evidence for patients’safe use of nano-TiO2 .
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Objective:To observe the disinfection efficiency of N-doped nano-TiO2 on the curing light-guide rods.Methods:50 light-guide rods from 6 dental clinics were included,the bacteria adhesion on the light-guide rods before and after disinfection with N-doped nano-TiO2 was investigated using ATP bioluminescence method.Results:The RLU value of light-guide rods exposed to the air was 51 -649 before the use of N-doped nano-TiO2 disinfection,after spraying N-doped nano-TiO2 ,the RLU value of light-guide rods was 0 -6(P <0.01 ).Conclusion:N-doped nano-TiO2 has significant sterilization effect on the curing light-guide rods.
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This study focused on the photocatalytic destruction of dichloromethane (DCM) in indoor air using the nano-TiO2 /LDPE composite film as an economical photocatalyst. The nano-TiO2 was dispersed in a polyethylene matrix to form composite film. The photocatalytic activity of the nano-TiO2/LDPE composite films was evaluated through the degradation of dichloromethane (DCM) under UV-C irradiance at specific wavelength of 254 nm. The percentage of nano-TiO2 contents varied from 0, 5, and 10% (wt cat./wt LDPE composite film). The results derived from the kinetic model revealed that the photocatalytic rates of 5 and 10 wt.% nano-TiO2/LDPE composite films follow the first order reaction while the rate of the film without TiO2 followed the zero order reaction. At low concentration of DCM, the rate of photocatalytic degradation of the DCM was slower than that at high DCM concentration. The 10 wt.% of TiO2 content of the nano-TiO2/LDPE composite film yielded the highest degradation efficiency of 78%, followed by the removal efficiency of 55% for the 5 wt.% of TiO2 content of the nano-TiO2/LDPE composite film. In contrast with the composite film containing nano-TiO2, the LDPE film without adding nano-TiO2 expressed the degradation efficiency of 28%.
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This study investigated the conjoined cellular oxidative damage of human embryo kidney 293T (HEK293T) cells induced by cadmium chloride (CdCl2) and nanometer titanium dioxide (nano-TiO2).RT-PCR technique was used to detect the expressions of Heme oxygenase-1(HO-1) and 8-oxoguanine DNA glycosylase (OGG1).The activities of superoxide dismutase (SOD) and catalase enzyme (CAT) and concentrations of reactive oxygen species (ROS) and maldondialdehyde (MDA)were measured by different approaches.The results showed that CdCl2 and nano-TiO2 at a low concentration of 0.75 total toxic unit (TU) exerted an additive effects on HO-1 gene expression,CAT activities and MDA concentrations.When the total TU was increased to 1 or 1.25 TU,the interaction was synergetic.Moreover,the mixture with high proportion of CdCl2 produced an additive effect on the OGG1gene expression,and the interaction was changed to be synergetic when the concentration of CdCl2 was lower than or equal to that of nano-TiO2.Synergetic effects of CdCl2 and nano-TiO2 on cellular oxidative damage of HEK293T cells were found as indicated by the changes in the SOD activities and ROS concentrations.It was concluded that CdCl2 and nano-TiO2 exerts synergistic effects on the cellular oxidative damage of HEK293T cells,and the sensitivity of these indicators of oxidative damage varies with the proportion of CdCl2 and nano-TiO2 in the mixture.
ABSTRACT
This study investigated the conjoined cellular oxidative damage of human embryo kidney 293T (HEK293T) cells induced by cadmium chloride (CdCl2) and nanometer titanium dioxide (nano-TiO2).RT-PCR technique was used to detect the expressions of Heme oxygenase-1(HO-1) and 8-oxoguanine DNA glycosylase (OGG1).The activities of superoxide dismutase (SOD) and catalase enzyme (CAT) and concentrations of reactive oxygen species (ROS) and maldondialdehyde (MDA)were measured by different approaches.The results showed that CdCl2 and nano-TiO2 at a low concentration of 0.75 total toxic unit (TU) exerted an additive effects on HO-1 gene expression,CAT activities and MDA concentrations.When the total TU was increased to 1 or 1.25 TU,the interaction was synergetic.Moreover,the mixture with high proportion of CdCl2 produced an additive effect on the OGG1gene expression,and the interaction was changed to be synergetic when the concentration of CdCl2 was lower than or equal to that of nano-TiO2.Synergetic effects of CdCl2 and nano-TiO2 on cellular oxidative damage of HEK293T cells were found as indicated by the changes in the SOD activities and ROS concentrations.It was concluded that CdCl2 and nano-TiO2 exerts synergistic effects on the cellular oxidative damage of HEK293T cells,and the sensitivity of these indicators of oxidative damage varies with the proportion of CdCl2 and nano-TiO2 in the mixture.
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Objective To investigate the genetic damage of human bronchial epithelial cells (HBE) caused by cigarette smoke combined with nano-TiO2.Methods 16-HBE cells were exposed to cigarette smoke extract (CSE) and nano-TiO2(mg/L) at the doses of 0 mg/L CSE+0 mg/L nano-TiO2,50 mg/L CSE+0 mg/L nano-TiO2,75 mg/L CSE+0 mg/L nano-TiO2,100 mg/L CSE+0 mg/L nano-TiO2,0 mg/L CSE+10 mg/L nano-TiO2,50 mg/L CSE+10 mg/L nano-TiO2,75 mg/L CSE+10 mg/L nano-TiO2,100 mg/L CSE+10 mg/L nano-TiO2. After 24 h exposure,HBE viability was evaluated by the methyl thiazolyl tetrazolium (MTT) assay,single cell gel electrophoresis (SCGE,comet assay) was employed to assess DNA damage,chromosomal aberration was measured by micronucleus test. Results Except the group exposed to 10 mg/L nano-TiO2,HBE viability of the other treatment groups were lower than that of the control group and Comet % of the other treatment groups were higher than that of the control group (P