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Exposure to titanium dioxide and other metallic oxide nanoparticles induces cytotoxicity on human neural cells and fibroblasts.

Lai JC, Lai MB, Jandhyam S, Dukhande VV, Bhushan A, Daniels CK, Leung SW - Int J Nanomedicine (2008)

Bottom Line: Because the effects of such nanoparticles on human neural cells are unknown, we have determined the putative cytotoxic effects of these nanoparticles on human astrocytes-like astrocytoma U87 cells and compared their effects on normal human fibroblasts.We further noted that zinc oxide (ZnO) nanoparticles were the most effective, TiO(2) nanoparticles the second most effective, and magnesium oxide (MgO) nanoparticles the least effective in inducing cell death in U87 cells.Thus, our findings may have toxicological and other pathophysiological implications on exposure of humans and other mammalian species to metallic oxide nanoparticles.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, Idaho State University, Pocatello, ID 83209, USA.

ABSTRACT
The use of titanium dioxide (TiO(2)) in various industrial applications (eg, production of paper, plastics, cosmetics, and paints) has been expanding thereby increasing the occupational and other environmental exposure of these nanoparticles to humans and other species. However, the health effects of exposure to TiO(2) nanoparticles have not been systematically assessed even though recent studies suggest that such exposure induces inflammatory responses in lung tissue and cells. Because the effects of such nanoparticles on human neural cells are unknown, we have determined the putative cytotoxic effects of these nanoparticles on human astrocytes-like astrocytoma U87 cells and compared their effects on normal human fibroblasts. We found that TiO(2) micro- and nanoparticles induced cell death on both human cell types in a concentration-related manner. We further noted that zinc oxide (ZnO) nanoparticles were the most effective, TiO(2) nanoparticles the second most effective, and magnesium oxide (MgO) nanoparticles the least effective in inducing cell death in U87 cells. The cell death mechanisms underlying the effects of TiO(2) micro- and nanoparticles on U87 cells include apoptosis, necrosis, and possibly apoptosis-like and necrosis-like cell death types. Thus, our findings may have toxicological and other pathophysiological implications on exposure of humans and other mammalian species to metallic oxide nanoparticles.

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Increases in PI-stained cells after exposure of human astrocytoma (astrocytes-like) U87 cells to TiO2 microparticles or nanoparticles.Notes: U87 cells were treated with TiO2 microparticles or nanoparticles for 48 hours, then stained with PI, and the stained cells were photographed at a magnification of 100. The treatments were: A) control (ie, untreated) U87 cells; B) cells treated with 1 μg/mL TiO2 microparticles; C) cells treated with 10 μg/mL TiO2 microparticles; D) cells treated with 50 μg/mL TiO2 microparticles; E) cells treated with 1 μg/mL TiO2 nanoparticles; F) cells treated with 10 μg/mL TiO2 nanoparticles; and G) cells treated with 50 μg/mL TiO2 nanoparticles.Abbreviations: PI, propidium iodide; TiO2, titanium dioxide.
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f5-ijn-3-533: Increases in PI-stained cells after exposure of human astrocytoma (astrocytes-like) U87 cells to TiO2 microparticles or nanoparticles.Notes: U87 cells were treated with TiO2 microparticles or nanoparticles for 48 hours, then stained with PI, and the stained cells were photographed at a magnification of 100. The treatments were: A) control (ie, untreated) U87 cells; B) cells treated with 1 μg/mL TiO2 microparticles; C) cells treated with 10 μg/mL TiO2 microparticles; D) cells treated with 50 μg/mL TiO2 microparticles; E) cells treated with 1 μg/mL TiO2 nanoparticles; F) cells treated with 10 μg/mL TiO2 nanoparticles; and G) cells treated with 50 μg/mL TiO2 nanoparticles.Abbreviations: PI, propidium iodide; TiO2, titanium dioxide.

Mentions: As noted under fluorescence microscopy, there were very few control (ie untreated) U87 cells stained with PI (Figure 5A), indicating that there were very few necrotic cells among the population of untreated U87 cells examined. After U87 cells had been treated with progressively increased concentrations of TiO2 microparticles (1, 10, or 50 μg/mL) for 48 hours, the number of cells stained with PI progressively increased (Figures 5B–5D), suggesting that the number of necrotic cells increased with increases in treatment levels. Similarly, the number of cells stained with PI likely progressively increased (Figures 5E–5G) with increases in the treatment level of TiO2 nanoparticles (1, 10, or 50 μg/mL for 48 hours) although the effects of the nanoparticles were somewhat less marked than those of the microparticles (Figures 5B–5D). It should be pointed out that we noticed that both TiO2 microparticles and nanoparticles interacted with the PI dye to yield some fluorescence in the absence of U87 cells, although their fluorescence was minimal (data not shown) compared those noted in the treated cells.


Exposure to titanium dioxide and other metallic oxide nanoparticles induces cytotoxicity on human neural cells and fibroblasts.

Lai JC, Lai MB, Jandhyam S, Dukhande VV, Bhushan A, Daniels CK, Leung SW - Int J Nanomedicine (2008)

Increases in PI-stained cells after exposure of human astrocytoma (astrocytes-like) U87 cells to TiO2 microparticles or nanoparticles.Notes: U87 cells were treated with TiO2 microparticles or nanoparticles for 48 hours, then stained with PI, and the stained cells were photographed at a magnification of 100. The treatments were: A) control (ie, untreated) U87 cells; B) cells treated with 1 μg/mL TiO2 microparticles; C) cells treated with 10 μg/mL TiO2 microparticles; D) cells treated with 50 μg/mL TiO2 microparticles; E) cells treated with 1 μg/mL TiO2 nanoparticles; F) cells treated with 10 μg/mL TiO2 nanoparticles; and G) cells treated with 50 μg/mL TiO2 nanoparticles.Abbreviations: PI, propidium iodide; TiO2, titanium dioxide.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2636591&req=5

f5-ijn-3-533: Increases in PI-stained cells after exposure of human astrocytoma (astrocytes-like) U87 cells to TiO2 microparticles or nanoparticles.Notes: U87 cells were treated with TiO2 microparticles or nanoparticles for 48 hours, then stained with PI, and the stained cells were photographed at a magnification of 100. The treatments were: A) control (ie, untreated) U87 cells; B) cells treated with 1 μg/mL TiO2 microparticles; C) cells treated with 10 μg/mL TiO2 microparticles; D) cells treated with 50 μg/mL TiO2 microparticles; E) cells treated with 1 μg/mL TiO2 nanoparticles; F) cells treated with 10 μg/mL TiO2 nanoparticles; and G) cells treated with 50 μg/mL TiO2 nanoparticles.Abbreviations: PI, propidium iodide; TiO2, titanium dioxide.
Mentions: As noted under fluorescence microscopy, there were very few control (ie untreated) U87 cells stained with PI (Figure 5A), indicating that there were very few necrotic cells among the population of untreated U87 cells examined. After U87 cells had been treated with progressively increased concentrations of TiO2 microparticles (1, 10, or 50 μg/mL) for 48 hours, the number of cells stained with PI progressively increased (Figures 5B–5D), suggesting that the number of necrotic cells increased with increases in treatment levels. Similarly, the number of cells stained with PI likely progressively increased (Figures 5E–5G) with increases in the treatment level of TiO2 nanoparticles (1, 10, or 50 μg/mL for 48 hours) although the effects of the nanoparticles were somewhat less marked than those of the microparticles (Figures 5B–5D). It should be pointed out that we noticed that both TiO2 microparticles and nanoparticles interacted with the PI dye to yield some fluorescence in the absence of U87 cells, although their fluorescence was minimal (data not shown) compared those noted in the treated cells.

Bottom Line: Because the effects of such nanoparticles on human neural cells are unknown, we have determined the putative cytotoxic effects of these nanoparticles on human astrocytes-like astrocytoma U87 cells and compared their effects on normal human fibroblasts.We further noted that zinc oxide (ZnO) nanoparticles were the most effective, TiO(2) nanoparticles the second most effective, and magnesium oxide (MgO) nanoparticles the least effective in inducing cell death in U87 cells.Thus, our findings may have toxicological and other pathophysiological implications on exposure of humans and other mammalian species to metallic oxide nanoparticles.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, Idaho State University, Pocatello, ID 83209, USA.

ABSTRACT
The use of titanium dioxide (TiO(2)) in various industrial applications (eg, production of paper, plastics, cosmetics, and paints) has been expanding thereby increasing the occupational and other environmental exposure of these nanoparticles to humans and other species. However, the health effects of exposure to TiO(2) nanoparticles have not been systematically assessed even though recent studies suggest that such exposure induces inflammatory responses in lung tissue and cells. Because the effects of such nanoparticles on human neural cells are unknown, we have determined the putative cytotoxic effects of these nanoparticles on human astrocytes-like astrocytoma U87 cells and compared their effects on normal human fibroblasts. We found that TiO(2) micro- and nanoparticles induced cell death on both human cell types in a concentration-related manner. We further noted that zinc oxide (ZnO) nanoparticles were the most effective, TiO(2) nanoparticles the second most effective, and magnesium oxide (MgO) nanoparticles the least effective in inducing cell death in U87 cells. The cell death mechanisms underlying the effects of TiO(2) micro- and nanoparticles on U87 cells include apoptosis, necrosis, and possibly apoptosis-like and necrosis-like cell death types. Thus, our findings may have toxicological and other pathophysiological implications on exposure of humans and other mammalian species to metallic oxide nanoparticles.

Show MeSH
Related in: MedlinePlus