[Effects of TiO2 nanoparticles on antioxidant function and element content of liver and kidney tissues in young and adult rats].

OBJECTIVE: To compare the effect of TiO2 nanoparticles on antioxidant function and element content of liver and kidney tissues in young and adult rats. METHODS: Forty-eight SD male rats, half in 4-week (youth) old and half in 9-week (adult) old rats, were randomly divided into 8 groups, which were exposed to TiO2 nanoparticles [(75 ± 15) nm, anatase] through intragastric administration at 0, 10, 50 and 200 mg/kg body weight every day for 30 days. The liver and kidney tissues were collected for antioxidant function and element content analysis. RESULTS: 200 mg/kg TiO2 nanoparticles exposure significantly increased the liver total superoxide dismutase (T-SOD) activity and the kidney reduced glutathione (GSH)/oxidized glutathione (GSSG) ratios in young rats, and significantly decreased the liver Mo, Co, Mn and P contents and the kidney Rb and Na contents in young rats. 200 mg/kg TiO2 nanoparticles exposure significantly increased GSH/GSSG ratios and Rb contents and decreased Na contents in the liver of adult rats. No significantly difference was found in antioxidant indexes and elements content in the kidney of adult rats between three experimental groups and control group. CONCLUSION: TiO2 nanoparticles can enhance the antioxidant capacity and decrease the elements content in rat liver and kidney tissues. The liver is the more sensitive target organ and the young animals are more susceptible to TiO2 nanoparticles toxicity by the oral routes.

[Comparative analysis for the cytotoxicity and genotoxicity of multi-walled carbon nanotubes with different lengths and surface modifications in A549 cells].

OBJECTIVE: To compare the cytotoxicity and DNA strand breakage induced by multi-walled carbon nanotubes (MWCNTs) with different lengths and different surface modifications in human alveolar type II cells (A549 cells). METHODS: Two different lengths (5-15 µm, 350-700 nm) of MWCNTs and three different kinds of surface modified MWCNTs (COOH-MWCNTs, NH2-MWCNTs, and Tau-MWCNTs) were used in the experiments. The short MWCNTs were used as pristine MWCNTs to compare with the 3 surface modified MWCNTs. The cytotoxicity was determined by cell counting kit-8 (CCK-8) assay at the concentrations of 2, 8, and 32 mg/L at hours 12, 24, 36, and 48 respectively. Single cell gel electrophoresis (SCGE) assay was performed to evaluate DNA strand breakage in A549 cells after 24 h treatment of 8 mg/L of each tested material. RESULTS: Long multi-walled carbon nanotubes (Long-MWCNTs) and short multi-walled carbon nanotubes (Short-MWCNTs) showed a dose-dependent cytotoxicity within the exposure time 12-48 h. Especially, Long-MWCNTs showed greater cytotoxicity than Short-MWCNTs from 24 to 48 h at the same concentration. The relative cell viability of the 3 surface modified MWCNTs was higher than that of the pristine MWCNTs at h 12 at the concentration of 32 mg/L [COOH-MWCNTs (86.55±1.80)%, NH2-MWCNTs (84.67±1.32)%, Tau-MWCNTs (80.15±3.53)% and Pristine-MWCNTs (71.44±5.58)%], at h 24 at the concentration of 8 mg/L [COOH-MWCNTs (96.74±1.00)%, NH2-MWCNTs (96.74±3.35)%, Tau-MWCNTs (106.39±3.83)% and Pristine-MWCNTs (91.02±2.53)%], at h 24 at the concentration of 32 mg/L [COOH-MWCNTs (80.88±2.67)%, NH2-MWCNTs (82.90±3.25)%, Tau-MWCNTs (82.55±3.32)% and Pristine-MWCNTs (76.08±4.27)%] and at h 36 at the concentration of 8 mg/L [COOH-MWCNTs (96.87±1.05)%, NH2-MWCNTs (96.66±4.76)%, Tau-MWCNTs (100.23± 2.84)% and Pristine-MWCNTs (89.61±3.78)%], and the differences were statistically significant (P<0.05). Compared with the Pristine-MWCNTs, the relative cell viability of the 3 surface modified MWCNTs didn't demonstrate a statistically significant difference (P>0.05) at other observation time and exposure concentrations. The DNA strand breakage of the 3 surface modified MWCNTs: the Olive tail moment of COOH-MWCNTs was 1.56±0.22, the Olive tail moment of NH2-MWCNTs 2.25±1.62 and the Olive tail moment of Tau-MWCNTs 2.23±0.94; the tail DNA% of COOH-MWCNTs was (3.96± 0.60)%, the tail DNA% of NH2-MWCNTs (6.16±4.68)% and the tail DNA% of Tau-MWCNTs (6.05±2.31)%, which were lower than that of the pristine MWCNTs (P<0.05), whose Olive tail moment was 3.00±0.64 and tail DNA% (8.23±2.27)%. Moreover, the COOH-MWCNTs induced the lowest DNA damage among the three modified MWCNTs. CONCLUSION: Long-MWCNTs compared with Short-MWCNTs demonstrated a greater cytotoxicity and lower DNA strand breakage damage. The surface modifications of MWCNTs can reduce the cytotoxicity and DNA strand breakage in A549 cells.

[Effect of titanium dioxide nanoparticles on hemogram in rats with gastric ulcer].

OBJECTIVE: To explore the effect of titanium dioxide (TiO2) nanoparticles on hemogram in rats with gastric ulcer. METHODS: Physicochemical properties of TiO2 nanoparticles were characterized. Twenty-four clear class SD male rats, aging 8 week-old, were randomly divided into 4 groups, 6 rats for each group. 20% acetic acid were injected into the rats' stomach on the border of gastric body and pyloric antrum, and hereby established the gastric ulcer model. The rats in 4 groups were exposed to TiO2 nanoparticles through intragastric administration at 0, 10, 50 and 200 mg/kg body weight respectively for 30 days. Afterwards, the rats were conducted blood routine test and blood coagulation test for analysis. RESULTS: TiO2 nanoparticles were anatase crystals, closely spherical shape, whose average grain diameter was (75 ± 15) nm. The levels of white blood cell (WBC) count ((8.48 ± 3.28)×109/L), lymphocyte (LYM) ((6.85 ± 2.53)×109/L), monocyte (MOD) ((0.27 ± 0.12)×109/L), granulocyte (GRN) ((1.37 ± 0.86)×109/L), red blood cell (RBC) ((8.20 ± 0.49)×109/L) and hematocrit (HCT) ((45.3 ± 1.4)%) in the 200 mg/kg dose group were significantly higher than those in the control group ((2.63 ± 0.34)×109/L, (2.25 ± 0.26)×109/L, (0.05 ± 0.06)×109/L, (0.33 ± 0.26)× 109/L, (4.87 ± 2.37)×109/L and (27.2 ± 13.3)%, respectively; t values were -3.449, -3.825, -3.554, -3.097, -2.972 and -2.936 respectively, P values all < 0.05). The levels of WBC ((6.88 ± 3.06)×109/L), MOD ((0.20 ± 0.07)×109/L), RBC ((7.79 ± 0.48)×109/L) and HCT ((42.7 ± 2.8)%) in 50 mg/kg dose group were also statistically higher than those in the control group (t values were -2.507, -2.367, -2.605 and -2.511 respectively, all P values < 0.05). There was no statistically difference found in other blood routine index and coagulation index between the three experimental groups and control group. CONCLUSION: The long term intake of TiO2 nanoparticles caused a statistically increase in the amount of WBC and RBC in rats with gastric ulcer; however, there was no obvious changes found in blood platelet and coagulation index.