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Lung exposure of titanium dioxide nanoparticles induces innate immune activation and long-lasting lymphocyte response in the Dark Agouti rat.

Gustafsson Å, Lindstedt E, Elfsmark LS, Bucht A - J Immunotoxicol (2011)

Bottom Line: Inhalation of metal oxide nanoparticles in high doses may lead to both acute and long-standing adverse effects.Lymphocytes recruited to the lungs were predominantly CD4(+) helper T-cells, but we also demonstrated presence of CD8(+) T-cells, B-cells, and CD25(+) T-cells.In serum, we detected both an early cytokine expression at Days 1-2 (IL-2, IL-4, IL-6, CINC-1, IL-10, and interferon-gamma [IFN-γ] and a second response at Day 16 of tumor necrosis factor-alpha (TNF-α), indicating systemic late-phase effects in addition to the local response in airways.

View Article: PubMed Central - PubMed

Affiliation: Division of CBRN Defense and Security, Swedish Defense Research Agency, Umeå, Sweden. asa.gustafsson@foi.se

ABSTRACT
Nanomaterial of titanium dioxide (TiO(2)) is manufactured in large-scale production plants, resulting in risks for accidental high exposures of humans. Inhalation of metal oxide nanoparticles in high doses may lead to both acute and long-standing adverse effects. By using the Dark Agouti (DA) rat, a strain disposed to develop chronic inflammation following exposure to immunoactivating adjuvants, we investigated local and systemic inflammatory responses after lung exposure of nanosized TiO(2) particles up to 90 days after intratracheal instillation. TiO(2) induced a transient response of proinflammatory and T-cell-activating cytokines (interleukin [IL]-1α, IL-1β, IL-6, cytokine-induced neutrophil chemoattractant [CINC]-1, granulocyte-macrophage colony-stimulating factor [GM-CSF], and IL-2) in airways 1-2 days after exposure, accompanied by an influx of eosinophils and neutrophils. Neutrophil numbers remained elevated for 30 days, whereas the eosinophils declined to baseline levels at Day 8, simultaneously with an increase of dendritic cells and natural killer (NK) cells. The innate immune activation was followed by a lymphocyte expansion that persisted throughout the 90-day study. Lymphocytes recruited to the lungs were predominantly CD4(+) helper T-cells, but we also demonstrated presence of CD8(+) T-cells, B-cells, and CD25(+) T-cells. In serum, we detected both an early cytokine expression at Days 1-2 (IL-2, IL-4, IL-6, CINC-1, IL-10, and interferon-gamma [IFN-γ] and a second response at Day 16 of tumor necrosis factor-alpha (TNF-α), indicating systemic late-phase effects in addition to the local response in airways. In summary, these data demonstrate a dynamic response to TiO(2) nanoparticles in the lungs of DA rats, beginning with an innate immune activation of eosinophils, neutrophils, dendritic cells, and NK cells, followed by a long-lasting activation of lymphocytes involved in adaptive immunity. The results have implications for the assessment of risks for adverse and persistent immune stimulation following nanoparticle exposures in sensitive populations.

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Dose-dependent differences in the number of cells in bronchoalveolar lavage fluid from rats 24h after intratracheal instillation with nanosized TiO2. One-way ANOVA with Dunnett's post-test; value is significantly (*P < 0.05 and **P < 0.01) different vs. phosphate-buffered saline (PBS) control. Data are presented as mean ± SEM (n = 6).
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fig1: Dose-dependent differences in the number of cells in bronchoalveolar lavage fluid from rats 24h after intratracheal instillation with nanosized TiO2. One-way ANOVA with Dunnett's post-test; value is significantly (*P < 0.05 and **P < 0.01) different vs. phosphate-buffered saline (PBS) control. Data are presented as mean ± SEM (n = 6).

Mentions: The number of leukocytes in the lungs 1 day after lung exposure to increasing concentrations of TiO2 NPs (0, 1, 5, and 7.5 mg/kg body weight) was evaluated. A dose-dependent increase in eosinophils and neutrophils, as well as a decrease in macrophages (Figure 1), was detected. For further analysis, the 5 mg/kg dose was chosen to investigate the effects at 1, 2, 8, 16, 30, and 90 days post-exposure. The dose selected was the lowest that resulted in significantly increased leukocyte response in BALF 1 day after exposure.


Lung exposure of titanium dioxide nanoparticles induces innate immune activation and long-lasting lymphocyte response in the Dark Agouti rat.

Gustafsson Å, Lindstedt E, Elfsmark LS, Bucht A - J Immunotoxicol (2011)

Dose-dependent differences in the number of cells in bronchoalveolar lavage fluid from rats 24h after intratracheal instillation with nanosized TiO2. One-way ANOVA with Dunnett's post-test; value is significantly (*P < 0.05 and **P < 0.01) different vs. phosphate-buffered saline (PBS) control. Data are presented as mean ± SEM (n = 6).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3104284&req=5

fig1: Dose-dependent differences in the number of cells in bronchoalveolar lavage fluid from rats 24h after intratracheal instillation with nanosized TiO2. One-way ANOVA with Dunnett's post-test; value is significantly (*P < 0.05 and **P < 0.01) different vs. phosphate-buffered saline (PBS) control. Data are presented as mean ± SEM (n = 6).
Mentions: The number of leukocytes in the lungs 1 day after lung exposure to increasing concentrations of TiO2 NPs (0, 1, 5, and 7.5 mg/kg body weight) was evaluated. A dose-dependent increase in eosinophils and neutrophils, as well as a decrease in macrophages (Figure 1), was detected. For further analysis, the 5 mg/kg dose was chosen to investigate the effects at 1, 2, 8, 16, 30, and 90 days post-exposure. The dose selected was the lowest that resulted in significantly increased leukocyte response in BALF 1 day after exposure.

Bottom Line: Inhalation of metal oxide nanoparticles in high doses may lead to both acute and long-standing adverse effects.Lymphocytes recruited to the lungs were predominantly CD4(+) helper T-cells, but we also demonstrated presence of CD8(+) T-cells, B-cells, and CD25(+) T-cells.In serum, we detected both an early cytokine expression at Days 1-2 (IL-2, IL-4, IL-6, CINC-1, IL-10, and interferon-gamma [IFN-γ] and a second response at Day 16 of tumor necrosis factor-alpha (TNF-α), indicating systemic late-phase effects in addition to the local response in airways.

View Article: PubMed Central - PubMed

Affiliation: Division of CBRN Defense and Security, Swedish Defense Research Agency, Umeå, Sweden. asa.gustafsson@foi.se

ABSTRACT
Nanomaterial of titanium dioxide (TiO(2)) is manufactured in large-scale production plants, resulting in risks for accidental high exposures of humans. Inhalation of metal oxide nanoparticles in high doses may lead to both acute and long-standing adverse effects. By using the Dark Agouti (DA) rat, a strain disposed to develop chronic inflammation following exposure to immunoactivating adjuvants, we investigated local and systemic inflammatory responses after lung exposure of nanosized TiO(2) particles up to 90 days after intratracheal instillation. TiO(2) induced a transient response of proinflammatory and T-cell-activating cytokines (interleukin [IL]-1α, IL-1β, IL-6, cytokine-induced neutrophil chemoattractant [CINC]-1, granulocyte-macrophage colony-stimulating factor [GM-CSF], and IL-2) in airways 1-2 days after exposure, accompanied by an influx of eosinophils and neutrophils. Neutrophil numbers remained elevated for 30 days, whereas the eosinophils declined to baseline levels at Day 8, simultaneously with an increase of dendritic cells and natural killer (NK) cells. The innate immune activation was followed by a lymphocyte expansion that persisted throughout the 90-day study. Lymphocytes recruited to the lungs were predominantly CD4(+) helper T-cells, but we also demonstrated presence of CD8(+) T-cells, B-cells, and CD25(+) T-cells. In serum, we detected both an early cytokine expression at Days 1-2 (IL-2, IL-4, IL-6, CINC-1, IL-10, and interferon-gamma [IFN-γ] and a second response at Day 16 of tumor necrosis factor-alpha (TNF-α), indicating systemic late-phase effects in addition to the local response in airways. In summary, these data demonstrate a dynamic response to TiO(2) nanoparticles in the lungs of DA rats, beginning with an innate immune activation of eosinophils, neutrophils, dendritic cells, and NK cells, followed by a long-lasting activation of lymphocytes involved in adaptive immunity. The results have implications for the assessment of risks for adverse and persistent immune stimulation following nanoparticle exposures in sensitive populations.

Show MeSH
Related in: MedlinePlus