TiO2 nanoparticles translocation and potential toxicological effect in rats after intraarticular injection.

Recently, nanomaterials coating gained much concern in orthopedic implants such as bone, cartilage, joint, etc. The wear particles would generate from coating in living organism due to corrosion. In this study, we demonstrated that the intraarticular injected anatase TiO2 nanoparticles had a potential toxicological effect on major organs and knee joints of rats. The histopathological changes of heart, lung and liver indicated the dissemination of intraarticular TiO2 nanoparticles from joint cavity to system. In the knee joint, the aggregated TiO2 nanoparticles deposited and resulted in the synovium hypotrophy and lymphocytes and plasma cells infiltration, but had no effects on cartilage. In the TiO2-exposed synovium, the oxidative damage was induced because the glutathione peroxidase (GSH-Px), reduced glutathione (GSH), oxidized glutathione (GSSG), and superoxide dismutase (SOD) levels were highly regulated to counteract over-produced free radicals, i.e. hydrogen peroxide (H2O2). Further, the lipid peroxidation was detected in the synovium though the expression of proinflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha) and interleukin (IL-1beta) was not much interfered. This research suggested that the amounts of nanocoating in the surface of implants should be controlled and standardized.

[Influence of intranasal instilled titanium dioxide nanoparticles on monoaminergic neurotransmitters of female mice at different exposure time].

OBJECTIVE: To investigate the influence of intranasal instilling titanium dioxide (TiO2) nanoparticles on monoaminergic neurotransmitters at different-time exposure. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

[Analysis of total mercury and methylmercury concentrations in four commercially important freshwater fish species obtained from Beijing markets].

OBJECTIVE: The present paper makes an attempt to evaluate the risk of mercury exposure to human by analyzing the total mercury and methylmercury concentrations of four commercially important freshwater fish species in Beijing market. METHODS: Fish samples of common carp, grass carp, bighead carp, and snakehead were purchased from Beijing market. Then their muscle, liver and gills were taken out. The total mercury and methylmercury concentrations were determined using ultrasonic-assisted solvent extraction coupled with inductively coupled plasma-mass spectrometry. Samples were digested with 6mol/L HCl and sonicated for 2 hours. Subsequently, some aliquots were directly diluted for determination of total mercury concentrations; the remained extracts were extracted with CH2 C12 , and then back extracted with H20 for determination of methylmercury concentrations. To evaluate the validity of the method, the standard materials of DORM-2 and DOLT-3 were also measured. RESULTS: According to the concentrations oof total mercury and methylmercury in the muscles, an order was obtained as: snakehead > bighead carp > grass carp > common carp, which showed that the accumulation of mercury in fish was closely related to food chain. Methylmercury were about 80% of the total mercury, whereas there was a positive relationship between total mercury and methylmercury. The mercury distributions in the bighead carp and snakehead fish showed that the order of mercury concentrations was: muscle > liver > gill, the ratio of methylmercury to total mercury was: muscle > gill > liver. Methylmercury was mainly accumulated in the muscle of fish. CONCLUSION: mercury concentrations of the four fishes in Beijing markets were all below the standard level according to the National Standard of China, therefore, it is safe to human health.