BACKGROUND:Non-spherical titanium dioxide (TiO2) nanoparticles have been increasingly applied in various biomedical and technological fields. Their toxicological characterization is, however, less complete than that of roundish nanoparticles.MATERIALS AND METHODS:Anatase form TiO2 nanorods, ca. 15x65 nm in size, were applied to cultured astrocytes in vitro and to the airways of young adult Wistar rats in vivo in 5, 10, and 8 mg/kg BW dose for altogether 28 days. Presence of nanorods and cellular damage was investigated in the astrocytes and in rat lungs and kidneys. Functional damage of the nervous system was studied by electrophysiological methods.RESULTS:The treated astrocytes showed loss of viability without detectable apoptosis. In rats, TiO2 nanorods applied to the airways reached the blood and various organs including the lungs, kidneys, and the central nervous system. In lung and kidney samples, nanorods were observed within (partly damaged) phagolysosomes and attached to organelles, and apoptotic cell death was also detected. In cortical and peripheral electrophysiological activity, alterations corresponding to energy shortage (resulting possibly from mitochondrial damage) and astrocytic dysfunction were detected. Local titanium levels and relative weight of the investigated organs, apoptotic cell death in the lungs and kidneys, and changes in the central and peripheral nervous activity were mostly proportional to the applied doses, and viability loss of the cultured astrocytes was also dose-dependent, suggesting causal relationship of treatments and effects.CONCLUSION:Based on localization of the visualized nanorods, on neuro-functional changes, and on literature data, the toxic mechanism involved mitochondrial damage, oxidative stress, and apoptotic cell death. These indicate potential human toxicity and occupational risk in case of exposure to rod-shaped TiO2 nanoparticles.

INTRODUCTIONThe development of nanotechnology increases the risk of occupational and population-level exposure to nanoparticles nowadays. However, scientifically based knowledge relating to the toxicity of heavy metal nanoparticles and potential health damage is insufficient.AIMInvestigation of lung tissue damage induced by titanium dioxide (TiO2) nanorods in subacute intratracheal instillation by morphological, chemical and biochemical methods in rat model.METHODGeneral toxicity (changes of body and organ weights), local acute and chronic cellular toxicity (in alveolar spaces and epithelium, in hilar lymph nodes) and oxidative stress were examined using light and electron microscopy, and biochemical methods (reactive oxygen species, lipid peroxidation, expression of pro-inflammatory cytokines).RESULTSNo dose- and time-dependent alteration was found in the body weight of the treated groups; but the mass and Ti content of lungs increased with dose. Light and electron microscopy of the lung tissue verified the presence of nanoparticles, free in the alveolar space and within phagosomes of macrophages not attached to alveolar epithelium. Chronification of local acute alveolitis was supported by dose-dependent increase of macrophage count in the alveolar region, oedema and thickening of interstitium, and increased expression of certain pro-inflammatory cytokines (interleukin-1a, LIX, L-selectin, vascular endothelial growth factor). Oxidative stress and lipid peroxidation increased substantially in the treated rats' lungs, and correlation was found between Ti content and lipid peroxidation. Insufficiency of the alveolar epithelial and capillary endothelial barrier was indicated by nanoparticle-laden phagocytes in hilar lymph nodes, suggesting nanoparticles reaching systemic circulation and distant organs, inducing systemic acute inflammation.CONCLUSIONTiO2 nanoparticles, reaching lower airways, may be etiological factors in the causation or aggravation of pulmonary diseases with acute and chronic airways inflammation and/or progressive fibrosis and obstruction (e.g., chronic obstructive pulmonary disease or asthma). Autophagy and damaged immune response (lymphocytic activity) may have here a role. Orv Hetil. 2019; 160(2): 57-66.

A kutatás célja a Szegedi Tudományegyetemen ápolt és influenza fertőzésre fokozottan fogékonyak ellátását végző egészségügyi dolgozók és hallgatók influenza oltási magatartásának megismerése és a szokásokat meghatározó tényezők azonosítása.

1. Horváth T, Papp A, Kozma G, Kiricsi M, Igaz N, Kálomista I, Vezér T: General and nervous system toxicity of titanium dioxide nanoparticles investigated by in vivo and in vitro methods. NKE XI. Konferenciája "Krónikus betegségek megelőzése". Szeged; 2017.08.30 09.01. Népegészségügy 95:160-161. (2017) 2. Horváth T, Kozma G, Kovács D, Kálomista I, Vezér T, Papp A: Funkcionális idegrendszeri változások vizsgálata titán-dioxid nanorészecskékkel kezelt patkányokban. Magyar Élettani, Klinikai és Kísérletes Farmakológiai, Mikrocirkulációs és Vaszkuláris Biológia Társaságok Közös Tudományos Konferenciája, Debrecen, 2017.06. 13. 06.16. Absztrakt P 1.1.8., pp.9-10.

Background: Titanium dioxide nanoparticles have numerous applications, resulting in human exposure. Nonetheless, available toxicological and safety data are insufficient regarding aspherical particles, such as rod-shaped nanoparticles. Methods: In a combined in vitro in vivo approach, cultured A549 lung alveolar adenocarcinoma cells were treated with approximately 15x65 nm TiO2 nanorod-containing medium, while young adult rats received the same substance by intratracheal instillation for 28 days in 5 and 18 mg/kg body-weight doses. Nanoparticle accumulation in the lungs and consequent oxidative stress, cell damage, and inflammation were assessed by biochemical and histopathological methods. Results: Titanium was detected in tissue samples by single-particle inductively coupled plasma mass spectrometry. Nanoparticles were visualized inside cultured A549 cells, within pulmonary macrophages, and in hilar lymph nodes of the rats. A549 cells showed dose-dependent oxidative stress and lethality, and the observed nanoparticle-laden endosomes suggested deranged lysosomal function and possible autophagy. Strongly elevated Ti levels were measured in the lungs of nanorod-treated rats and moderately elevated levels in the blood of the animals. Numerous cytokines, indicating acute and also chronic inflammation, were identified in the lung samples of TiO2-exposed rodents. Conclusion: Several signs of cell and tissue damage were detected in both the cultured alveolar cells and in treated rats' lungs. Rod-shaped nanoparticulate TiO2 may consequently be more harmful than has generally been supposed. The occupational health risk suggested by the results calls for improved safety measures.

A total of forty, 7-week-old male rats were exposed to the 'rodentized' version (twice as fast as and one octave higher than the original) of Mozart's Sonata for Two Pianos in D major for ten minutes a day for 10 weeks. One group (10 rats) received the musical stimuli before ('B'), another during ('D') and the third before and during ('BD') the memory test, while the ten control ('C') animals were kept in silence. The animals' spatial learning and memory ability was tested in an 8-arm radial maze. Rats exposed to the music showed a significant (7.1%) improvement in task acquisition (Group BD), but it did not practically change in Group D and worsened by 10.5% in Group B. The 2-h working memory significantly improved by 12.1% (BD) while practically did not change in Groups B and D. The reference memory improved by 11.9% in Group BD, but did not change in Group B and D, compared to the Control. The performance of the groups during the 4-h working memory test did not differ significantly. During the long-term test period the spatial memory performance of the music-exposed rats did not show significant differences compared to the Control (Table 1). At the same time, most results obtained in the long-term period were better than the corresponding short-term data. In conclusion, this particular piece of music, falling within the rats' hearing range, was suitable for improving hippocampus-dependent spatial learning capacity, but only if the animals were exposed to it not only before but also during the task.

Background and purposeNanoparticles of titanium dioxide are suspected neurotoxic agents and have numerous applications possibly resulting in human exposure by several ways including inhalation. In the present work, rats were exposed to spherical TiO2 nanoparticles of two different sizes by the intratracheal route. It was investigated how the neuro-functional alterations, detected by electrophysiological and behavioral methods, were related to the concentration of Ti in the tissue samples and what the influence of the size of the NPs was.MethodsRats (young adult Wistar males, 10/group) were exposed to TiO2 nanoparticles of ca. 10 and 100 nm diameter (suspension medium: neutral PBS with 1% hydroxyethyl cellulose) by intratracheal instillation in 5 and 18 mg/kg b.w. dose; 5 days per week for 6 weeks. Controls were instilled with saline, and vehicle controls, with the suspension medium. To see general toxicity, body weight was checked daily, and organ weights were measured at the end of experiment. Grip strength test, to assess motor function damage, was done before and after the 6-week treatment. Finally, the rats were anesthetized with urethane, spontaneous cortical activity and sensory evoked potentials were recorded, then the rats were dissected and tissue samples were taken for Ti level measurement.ResultsBody weight gain indicated no general toxicity, and no significant change in the relative organ weights, except that of the lungs, was seen. However, change of time-to-fall in the grip strength test, and latency of cortical evoked po-tentials, were altered in the treated groups, indicating functional damage. Correlation of these alterations with the cortical Ti level was dissimilar for the two sizes of nanoparticles.ConclusionThe results provided further support to the functional neurotoxicity of TiO2 nanoparticles. The exact role of particle size, and the mechanisms involved, remain to be elucidated.

Introduction and aims - Particles of titanium dioxide (TiO2) with typical size below 100 nm have gained a broad range of application by now, partly involving direct human exposure. Their known properties - high specific surface, mobility within the organism, induction of oxidative stress, release of inflammation mediators etc. - raise the possibility of nervous system damage but the available data regarding this are scarce and contradictory. Based on that, and the experiences with other metal oxide nanoparticles, the aim of the present study was to investigate certain general end nervous system toxic effects of TiO2 nanoparticles applied in the airways of rats. Materials and methods - Young adult Wistar rats (5 groups of 10 rats each) received, daily for 28 days, intratracheal instillations of titanium dioxide nanoparticles of ca. 10 nm diameter, suspended in 1% hydroxyethyl cellulose dissolved in phosphate-buffered saline, in the doses of 1, 3, and 10 mg/kg b. w. Vehicle controls received the suspension medium and there was also an untreated control group. During treatment, the rats’ body weight was measured, and their clinical state observed, daily. After the 28 days, spontaneous cortical activity, sensory evoked potentials and tail nerve action potential was recorded in urethane anesthesia, then the rats were dissected and tissue samples were taken for Ti level determination and biochemical measurements of some oxidative stress indicators. Results - The two higher doses reduced the rate of body weight gain significantly. Sensory evoked potentials and tail nerve action potential were significantly slowed, but the change in the spectrum of spontaneous cortical activity was not significant. Correlation of moderate strength was found between certain evoked potential parameters and brain Ti level and oxidative stress data. Conclusion - Our results underlined the possible neurotoxicity of TiO2 NPs but also the need for further investigations.

Introduction and aims - Particles of titanium dioxide (TiO2) with typical size below 100 nm have gained a broad range of application by now, partly involving direct human exposure. Their known properties high specific surface, mobility within the organism, induction of oxidative stress, release of inflammation mediators etc. raise the possibility of nervous system damage but the available data regarding this are scarce and contradictory. Based on that, and the experiences with other metal oxide nanoparticles, the aim of the present study was to investigate certain general end nervous system toxic effects of TiO2 nanoparticles applied in the airways of rats.Materials and methods - Young adult Wistar rats (5 groups of 10 rats each) received, daily for 28 days, intratracheal instillations of titanium dioxide nanoparticles of ca. 10 nm diameter, suspended in 1% hydroxyethyl cellulose dissolved in phosphate-buffered saline, in the doses of 1, 3, and 10 mg/kg b. w. Vehicle controls received the suspension medium and there was also an untreated control group. During treatment, the rats' body weight was measured, and their clinical state observed, daily. After the 28 days, spontaneous cortical activity, sensory evoked potentials and tail nerve action potential was recorded in urethane anesthesia, then the rats were dissected and tissue samples were taken for Ti level determination and biochemical measurements of some oxidative stress indicators.Results - The two higher doses reduced the rate of body weight gain significantly. Sensory evoked potentials and tail nerve action potential were significantly slowed, but the change in the spectrum of spontaneous cortical activity was not significant. Correlation of moderate strength was found between certain evoked potential parameters and brain Ti level and oxidative stress data.Conclusion - Our results underlined the possible neurotoxicity of TiO2 NPs but also the need for further investigations.

Consequences of oral arsenic and fluoride exposure on motor behavior and general toxicity were modeled in young adult male rats which received sodium (meta)arsenite (10mg/kg b.w.), sodium fluoride (5mg/kg b.w.), and their combination by gavage, once daily, 5days a week for 6weeks. After 6weeks, 6 animals per group were dissected, while the other 6 were kept for 6 more weeks untreated. Body weight, together with food and water consumption, was measured daily. Arsenic, alone or along with fluoride, caused significant decrease in rearing, and increase in immobility and local activity in the open field in the 3rd and 6th week. By the 12th week, these changes mostly diminished. Weight gain, and food and water consumption were significantly reduced by arsenic but normalized post treatment. Fluoride had no own effect and mostly no influence on effects of arsenic. Massive deposition of arsenic in the rats' blood, cerebral cortex, and liver by the 6th week, and partial elimination by the 12th week, was seen. The results underline the risk of neuro-functional damage by arsenic and call for further investigations.

The so-called "Mozart effect" indicated that a musical environment might improve the learning capacity and spatial intelligence. After 1 week adaptation and 1 week acquisition period 12 male rats were exposed once a day to a 8.5-min-long arrangement of Mozart Sonata for Two Pianos in D Major (K 448). The animals' spatial learning and memory ability was tested in an 8-arm radial maze. Week 1 (adaptation); all animals had a 10-minute training twice a day, adapting them to find feed pellets in the maze arm ends. Week 2 (acquisition of the task): with one training per day, the rats were first individually trained to learn the general cues of the task, that is, entering each one of the 8 arms only once in a given session, with no more than one error per session in 6 consecutive days. Acquisition errors consisted of revisiting an arm previously entered in the same session. The percent rate of correct responses was counted as (correct responses/acquisition errors) x 100, and was taken as performance indicator. Week 3 and 5 (short-term working memory test): the rats (all 12 per group) were one by one put for 10 min maximum in the centre of the maze, but they were allowed to enter only 4 of the 8 open and baited arms; this was the "event-to-be-remembered". After visiting the four arms, the animal was returned to its cage and kept there for 2 (on week 3) or 4 hours (on week 5). The rats were then put again in the maze centre and allowed to complete arm choices 5-8 to obtain rewards in the 4 baited arms not visited before. In the working memory (WM) tests, WM errors meant re-entry into any of the arms visited in the first run. Week 4 (reference memory test): the feed reward was put only in the 4 arms preferred by the individual rats. Entering a non-baited (empty) arm constituted a reference memory error, from which performance was calculated. Week 6 and 7 (resting period): the animals were kept in the housing room, were exposed to the music once a day, but did not have any testing and were not exposed to new information. Week 8, 9 and 10 (long-term memory tests): in the 8th treatment week (recall), memory return was observed and in the 9th and 10th treatment week, 2- and 4-hours WM, respectively. The rats' spontaneous exploratory activity was investigated in an open field (OF) apparatus, measuring by infrared beam interruptions at the beginning, on the 5th and 10th week of it. There was a continuous white background noise (40 dB) and 25 lux illumination in the testing room. Rats, exposed to the acoustic exposure (Mozart music), tested by maze-learning capacity and memory performance, showed significant improvement of the short-term reference (59.76 +/- 4.24 vs. 75.36 +/- 5.53%, p=0.00155), in the return after the resting period (83.42 +/- 3.06 vs. 88.78 +/- 2.74%, p=0.01929), and 4-hour-interval long-term WM (60.52 +/- 2.49 vs. 65.97 +/- 2.87%, p=0.01258), control vs. musical group, respectively. The spontaneous locomotor activity of the control and music-exposed animals during the OF-test did not show significant differences. The urination and defecation activity during these mobility tests did not indicate any important difference between the emotional state of the control and music-treated rats. The subsequent classical (histo) pathological examination did not show any alterations, related to the musical treatment or substantial stress state. As a conclusion, this particular music in human hearing range was appropriate for improving learning capacity, but the spontaneous free-running movement practically did not change.In the present experiment the Mozart sonata proved to be efficient to improve some memory types without influencing the open-field results.

Oral exposure of humans by excess amounts of arsenic and/or fluorine may cause disturbances of the nervous system. In the present experiment, such exposure was modelled in rats, with general and behavioral endpoints being examined. Seven weeks old adult male SPF Crl:WI BR Wistar rats (160±20 g, 4 groups of 12 rats each) were treated with sodium (meta)arsenite (10 mg/kg b.w.; As), sodium-fluoride (5 mg/kg b.w.; F) and their combinations (As+F) per os by gavage, 5 days a week once a day for 6 weeks. An untreated control group was also used (Control). General toxicological parameters (body weight gain, food and water consumption) were measured daily. Behavioral investigations (rota-rod and open field) were done in the 4th and 6th weeks of treatment.Weekly body weight gain was significantly reduced in the As (vs. F) and As+F (vs. Control and F) groups from the first week on. This difference was seen during the whole treatment period, and was more prominent from the second week on (As and As+F vs. Control and F). As, but not F, affected the relative weight of the liver, spleen and kidneys. Food and water consumption in the As and As+F groups was significantly reduced vs. Control and F, while a non-significant increase of water consumption was seen in group F. In the open field test, As and As+F caused significant decrease in rearing and ambulation, and increase in immobility and local activity, vs. Control and F. In the rota rod performance, no noteworthy change was observed.In the treatment regime applied, significant effects on both general and behavioral endpoints by arsenic, but not by fluorine, were detected, which underlines the risk from environmental exposure.

The aim of this study was to determine the potential toxic effects of iron(II,III)oxide nanoparticles (IONPs). In in vivo experiments, the toxic effects of IONPs were monitored in adult male Wistar rats by morphological methods after a single intratracheal instillation. For the control group 1?ml of physiological saline per animal was given, and the treatment group received the same volume of a suspension containing 1 and 5?mg?kg-1 body weight IONPs. Lungs and internal organs underwent histopathological examination after 1, 3, 7, 14 and 30?days. The mutagenic effect of these nanoparticles was evaluated by the bacterial reverse mutation assay on Salmonella typhimurium TA98, TA100, TA1535 and TA1537 strains, and on Escherichia coli WP2uvrA strain, in the presence and absence of the mammalian metabolic activation system S9. The in vitro cytotoxic effect of IONPs was also examined in Vero cells after short-term (4?h) and long-term (24?h) exposure. There were no pathological changes in examined internal organs, except a very weak pulmonary fibrosis developing by the end of the first month in the treated rats. While in vitro MTT assay showed a moderate cytotoxic effect, IONPs proved to be devoid of mutagenic effect in the bacterial systems tested. The results may be a useful extension of our knowledge on the safety of magnetite nanoparticles in view of their possible medical applications, such as in hyperthermia and magnetic resonance imaging. Copyright (C) 2011 John Wiley & Sons, Ltd.

Context and objective: Lead (Pb) is a heavy metal harmful for human health and environment. From leaded gasoline (still used in certain countries), and in Pb processing and reprocessing industries, airborne particles are emitted which can be inhaled. In such exposure, the size of particles entering the airways is crucial. The nervous system is a primary target for Pb, and consequences like occupational neuropathy and delayed mental development of children are well-known. The aim of this work was to investigate the neurotoxicity of Pb nanoparticles (NPs) applied into the airways of rats.Methods: Nano-sized lead oxide particles (mean diameter ca. 20 nm) were suspended in distilled water and instilled into the trachea of adult male Wistar rats (in doses equivalent to 2 and 4 mg/kg Pb), 5 times a week for 3 and 6 weeks. At the end, open field motility was tested, then central and peripheral nervous activity was recorded in urethane anesthesia.Results and conclusion: The treated rats' body weight gain was significantly lower than that of the controls from the 3rd week onwards, and the weight of their lungs was significantly increased. Horizontal motility increased while vertical motility decreased. Spontaneous cortical activity was shifted to higher frequencies. The somatosensory cortical evoked potential showed increased latency and decreased frequency-following ability, and similar alterations were seen in the tail nerve. Significant Pb deposition was measured in blood, brain, lung and liver samples of the treated rats. The experiments performed seem to constitute an adequate model of the human effects of inhaled Pb NPs.

Airborne manganese represents a major risk of nervous system damage first of all in industrial settings. The resulting effects may depend on the dose and physicochemical form of Mn. To compare the effect of soluble and nanoparticulate Mn, adult male rats received daily instillation of MnCl(2) solution or MnO(2) nanoparticle suspension (dose: 2.53mg Mn per rat) into the nasal cavity for 3 and 6 weeks. At the end of treatment, spontaneous open field motility was tested, electrophysiological recording was done in anesthesia, and brain tissue Mn level was determined. Metal level increase in the rats' brain, body weight gain reduction, and decrease of open field motility was significant in the MnCl(2), but not nano-Mn, treated rats. Most evoked cortical activity parameters were significantly altered in both groups, but spontaneous cortical activity spectrum only in the rats receiving MnCl(2). There was fair correlation between brain Mn levels and certain neuro-functional parameters, underlining the causal relationship. Electrophysiological tests might be more sensitive to the effects of Mn than general toxicological or neurobehavioral tests.

Airborne metal-containing particles represent a known source of health risk but the role of nano-sized particles in the pathogenicity of dust has been recognized only recently. As a model of inhalational exposure to manganese, adult male Wistar rats were treated with a suspension of MnO(2) nanoparticles of ca. 23 nm diameter, instilled into the trachea for 3, 6, and 9 weeks in daily doses of 2.63 and 5.26 mg Mn/kg, and endpoints of functional neurotoxicity (open field behavior and electrophysiology) and general toxicity (body and organ weights) were investigated. Weekly body weighing showed that control rats had normal weight gain but the treated rats' body weight failed to increase from the 6th week on. Dissection and organ weighing after the corresponding treatment periods revealed dose- and time-dependently increased relative lung weights. In brain and blood samples, significantly elevated Mn level was detected after 9 weeks exposure. The treated rats' open field behavior showed decreased ambulation and rearing, and increased local activity and immobility. Electrophysiological investigations after 9 weeks exposure indicated a shift of the spontaneous cortical activity to higher frequencies, lengthened cortical evoked potential latency, and slowed nerve conduction. Several of these general and neuro-functional parameters were significantly correlated to the tissue Mn levels. Instilled Mn in nanoparticle form was indeed absorbed and exerted neurotoxic effects, so the model seems suitable for studying the effects of airborne nanoparticles, relevant to human health.