Changes of brain oxidative stress induced by nano-alumina in ICR mice / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the brain oxidative stress injury induced by nano-alumina particles in ICR mice.</p><p><b>METHODS</b>Sixty male ICR mice were randomly divided into 6 groups: control group, solvent control group, 100 mg/kg micro-alumina particles group, 3 groups exposed to nano-alumina particles at the doses of 50, 100 and 200 mg/kg. The mice were exposed by nasal drip for 30 days. Then levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-PX) in brain tissues of mice were detected.</p><p><b>RESULTS</b>There was no difference of SOD activity in mouse brain between control group [(17.32 +/- 6.23)U/gHb] and 50 mg/kg nano-alumina particles group [(17.89 +/- 1.82) U/gHb]. The SOD activity [(4.93 +/- 2.30)U/gHb] in 200 mg/kg nano-alumina particles group was significantly lower than that in control group (P < 0.05). The MDA levels in 3 nano-alumina particles groups were (0.76 +/- 0.13), (1.00 +/- 0.30) and (1.16 +/- 0.39)nmol/ml, respectively, which were significantly higher than that [( 0.24 +/- 0.09)nmol/ml] in control group (P < 0.05). The GSH levels in 3 nano-alumina particles groups were (0.72 +/- 0.08), (0.55 +/- 0.19) and (0.61 +/- 0.20)mg/gpro, respectively, which were significantly lower than that [(1.55 +/- 0.34)mg/gpro]] in control group (P < 0.05). The CAT activity in 50 and 100 mg/kg nano-alumina particles groups were (10.40 +/- 3.84) and (10.40 +/- 2.00)U/mgpro, respectively, which were significantly higher than that [(5.79 +/- 0.96) U/mgpro] in control group (P < 0.05). The CAT activity [(3.25 +/- 1.04)U/mgpro] in 200 mg/kg nano-alumina particles group was significantly lower than that in control group (P < 0.05 ).</p><p><b>CONCLUSION</b>Nano-alumina particles can induce the oxidative stress damage in brain tissues of mice.</p>

The effect of inhalable titanium dioxide on the oxidative stress among occupational population / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the inhalable titanium dioxide exposure level and make an assessment of its oxidative effect on occupational exposed population.</p><p><b>METHODS</b>A total of 7 workers occupationally exposing to inhalable titanium dioxide were recruited into the study. The basic information and occupational history were collected by interview, while their blood sample (10 ml for each subject) were collected before and after the investigation, respectively. Pre- and post-work shift urine samples (60 ml for each subject) were collected for 29 days consecutively. The daily personal titanium dioxide exposure level, temperature and relative humidity were detected too. Urinary 8-hydroxy-deoxyguanosine (8-OHdG) and serum high-sensitivity C-reactive protein (hs-CRP) were detected by ELISA and latex immunoturbidimetric assay, respectively.</p><p><b>RESULTS</b>The mean concentration of air inhalable titanium dioxide was (1.194 ± 1.015) mg/m(3). Serum hs-CRP level before and after the investigation was (1.13 ± 1.08), (1.33 ± 1.01) mg/L, respectively. No statistical significance was observed between hs-CRP level before and after the investigation (t = -0.848, P = 0.425). Pre- and post-work shift urinary 8-OHdG was (3.51 ± 1.39), (3.65 ± 1.06) µmol/mol Cr, respectively. A positive correlation was found between the concentration of inhalable titanium dioxide and the changes of 8-OHdG level (r = 0.192, t = 2.09, P = 0.039). Linear mixed-effect models, adjusted by work shift, years of employment, age, body mass index, smoking status, temperature and relative humidity, showed no significant exposure-respond trend between the inhalable titanium dioxide concentration and 8-OHdG level (β = 0.288, t = 1.940, P = 0.055).</p><p><b>CONCLUSION</b>Our findings do not support the potential link between occupationally exposure to inhalable titanium dioxide and high induction of DNA oxidative stress.</p>

Effect of nano-TiO(2) intratracheal instillation on lipid metabolism of AopE gene-knockout mice / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of nano-TiO(2) intratracheal instillation on the progression of dyslipidemia and atherosclerosis in apolipoprotein E-knockout mice.</p><p><b>METHODS</b>The nano-TiO(2) was ultrasound with phosphate-buffered saline solutions (PBS) into its suspension for exposure. A total of 46 specific pathogen free (SPF) level of 11-week-old male apolipoprotein E-knockout mice were randomly divided into groups by their body weights: non-treatment group (8 mice), PBS control group (9 mice), high dose group (1.0 mg/ml, 10 mice), medium dose group (0.5 mg/ml, 10 mice), and low dose group (0.1 mg/ml, 9 mice). Except the non-treatment group, mice from other groups were intratracheally instilled with 0.05 ml each time, twice a week. After exposure of 6 weeks, viscera index, blood TC, TG, HDL-C, LDL-C, and organic lipid ratio were assessed as biomarkers. Artery and aortic root issues were assessed by histopathology.</p><p><b>RESULTS</b>After 5 weeks exposure, mice body weights in high dose group ((29.7 ± 1.9) g) started to drop, compared to PBS control ((31.3 ± 1.9) g, t = -1.58, P < 0.05) and low dose group ((31.4 ± 1.4) g, t = -1.17, P < 0.05); after 6 weeks, high dose group ((28.8 ± 1.5) g) was lower than PBS control ((30.4 ± 1.9) g, t = -1.60, P < 0.05), non-treatment group ((30.2 ± 1.3) g, t = -1.43, P < 0.05) and low dose group ((30.6 ± 1.0) g, t = -1.83, P < 0.05). TC levels of non-treatment, PBS control, high dose group, medium dose group and low dose group were (2.92 ± 1.18), (3.12 ± 0.73), (4.19 ± 1.86), (3.46 ± 0.72) and (2.57 ± 0.64) mmol/L, respectively; TG levels were (0.39 ± 0.13), (0.39 ± 0.08), (0.60 ± 0.21), (0.55 ± 0.19) and (0.41 ± 0.11) mmol/L, respectively; HDL-C levels were (1.67 ± 0.45), (1.54 ± 0.67), (0.93 ± 0.50), (1.02 ± 0.48) and (1.31 ± 0.64) mmol/L; TG levels of high dose group were higher than that of non-treatment group (t = 1.27, P = 0.03) and low dose group (t = 1.62, P = 0.01); TG levels of medium dose group was higher than PBS control (t = 0.16, P = 0.04), and TC levels of high dose group were higher than PBS control (t = 0.22, P = 0.01), non-treatment group (t = 0.22, P = 0.04) and low dose group (t = 0.20, P = 0.03), and HDL-C levels of high dose group were lower than PBS control (t = -0.61, P = 0.04) and non-treatment group (t = -0.74, P = 0.04); organic lipid ratio of each group were (2.27 ± 0.51)%, (2.06 ± 0.53)%, (2.90 ± 0.50)%, (2.60 ± 0.23)%, (2.24 ± 0.45)%; high dose group were higher than PBS control (t = 0.85, P = 0.00), non-treatment group (t = 0.64, P = 0.03) and low dose group (t = 0.67, P = 0.01); medium dose group was higher than PBS control (t = 0.54, P = 0.02). The plaque lipid content and calcium content which showed the progression of atherosclerosis and plaque rupture were elevated in medium and high dose groups.</p><p><b>CONCLUSION</b>Intratracheal instillation of nano-TiO(2) can induce dyslipidemia and accelerate the development of atherosclerosis and plaque rupture in ApoE-/-mice.</p>

Influence of intranasal instilled titanium dioxide nanoparticles on monoaminergic neurotransmitters of female mice at different exposure time / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the influence of intranasal instilling titanium dioxide (TiO2) nanoparticles on monoaminergic neurotransmitters at different-time exposure.</p><p><b>METHODS</b>CD female mice were intranasally instilled three different-sized (25 nm, 80 nm and 155 nm) TiO, suspension every other day in a dose of 50 mg/kg body weight. The control group was instilled the same volume of Milli-Q water. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to analyze the titanium contents in murine brain after exposure to TiO2 particles 2 days, 10 days, 20 days and 30 days. The monoaminergic neurotransmitters such as norepinephrine (NE), dopamine (DA), 5-hydroxytryptamine (5-HT), 5-hydroxyindole acetic acid (5-HIAA), 3, 4-dihydroxyphenylacetic acid (DOPAC), and homovanillic (HVA), were determined by reversed-phase high performance liquid chromatography (RP-HPLC) with electrochemical detector.</p><p><b>RESULTS</b>After exposure to TiO, nanoparticles 10 days, the titanium contents in murine brain were increased, the titanium content in the 25 nm group was up to (1059.3 +/- 293.5) ng/g. In 20 days, the titanium content decreased slowly with the metabolism of titanium in vivo, but it kept at a high level, the content decreased to (654.7 +/- 269.2) ng/g in the 25 nm group. After exposure to TiO2 nanoparticles 30 days, the titanium contents had no obviously change. Because of the accumulation of TiO, in the brain, the contents of NE and 5-HT increased significantly after exposure to 80 nm and 155 nm TiO, nanoparticles 20 days, while the decreased contents of DA, DOPAC, HVA and 5-HIAA were observed.</p><p><b>CONCLUSION</b>The inhaled TiO2 nanoparticles could be translocated to and deposited in murine brain after absorbing by nasal mucosa, and further influence the releases and metabolisms of monoaminergic neurotransmitters in brain.</p>